Big Ideas Simply Explained - The Ecology Book

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РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 100 INTRODUCTION Dutch lens-makers Hans Louis Pasteur reveals Charles Elton publishes and Zacharias Janssen that wine’s fermentation Animal Ecology, which invent the compound process is caused by germs; his discovery sparks the sets out many of the microscope. development of germ theory. fundamental principles of animal behavior. 1590 1866 1927 1676 1885 Antonie van Albert Frank coins the Leeuwenhoek term “mycorrhizae,” in identifies “animalcules,” reference to the symbiotic opening up the field relationship between of microbiology. fungi and tree roots. Our understanding of the about them for many years. In trees with the fungi attached variety, behavior, and the 1860s, French chemist Louis to their roots were healthier than interraction of organisms Pasteur and German microbiologist those without. The fine filaments, has advanced considerably since Robert Koch developed the germ or hyphae, of the fungi make the Aristotle discovered that bee theory of disease, highlighting the roots more efficient at obtaining colonies have a queen and workers. harmful role played by bacteria. nitrate and phosphate nutrients Huge advances in technology, Subsequent research has also from the soil. In return, the fungi field observations, and laboratory highlighted their positive roles: get sugar and carbon from the tree. experiments have increased our facilitating digestion; inhibiting knowledge, and the modern study the growth of other, pathogenetic Connected lives of animal behavior—ethology— bacteria; “fixing” or converting No organism lives in isolation from continues to throw up surprises. nitrogen into molecules that aid the rest of its ecosystem. The plant growth; and breaking down behavioral interactions between Life under the microscope dead organic material, which them are complex and much is still Until the microscope was invented, releases nutrients for the food web. being discovered about them. One no one knew that bacteria even of the greatest contributions in this existed, let alone what they did. Another discovery made field was made by British zoologist Bacteria were first observed by possible by microscopy was of the Charles Elton, whose 1927 classic Dutch microscopist Antonie van mutualistic relationship between Animal Ecology established many Leeuwenhoek in 1676, using fungi and trees, published by important principles of animal an instrument he had built himself. German plant pathologist Albert behavior, including food webs and He called these tiny organisms Frank in 1885. Studying what he food chains, prey size, and the “animalcules,” but little was known first assumed was a pathological concept of ecological niches. infection, Frank discovered that

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 101 In Man Meets Insect Thermoregulation In the US, the Human Dog, Konrad Lorenz by Bernd Heinrich Microbiome Project is describes the instinctive launched, to map all the behavior of animals and explains how insects microbes associated with its evolutionary origins. are able to control their a healthy human body. own temperature. 1949 1981 2007 1947 1960 2005 David Lack publishes Jane Goodall sets up The first gene mapping an article on variations a camp in Tanzania to confirms that humans in bird clutch size as research chimpanzees in share 97–99 percent of the wild, discovering many their DNA with the other an evolutionary traits shared by humans. adaptation. great apes. Ethology, which looks at animal Field observations are a key tool in a red spot on a parent’s beak when behavior and its evolutionary basis ethological research. In the 1940s, they want food, will tap colored and development, is a major British ornithologist David Lack marks painted on a model beak. component in the modern study investigated the factors controlling of organisms. Back in 1837, British the number of eggs birds laid Human traits entomologist George Newport (clutch size). His food limitation As well as these short-term studies, discovered that moths and bees hypothesis states that the number British primatologist and ethologist could raise the temperature of their of eggs laid by a species has Jane Goodall conducted field thorax by quivering their muscles. evolved to match the food available. observations over a longer period, From the 1970s onward, German- Evolutionary pressure has created studying chimpanzees in Tanzania American entomologist Bernd a correlation between clutch size from 1960 to 1975. Her findings Heinrich and others uncovered and food availability. challenged the view that human more thermoregulatory adaptations behavior is totally unique in the that have helped insects thrive. Austrian zoologist Konrad animal world, and indicated that As heterotherms, they are able Lorenz and Dutch biologist Nikolaas chimps are behaviorally closer to maintain different temperatures Tinbergen also studied animals in to people than had generally been in different parts of the body. the wild to help understand their assumed. She noted, for example, behavior. Lorenz’s 1949 work Man that chimps display a whole range Modern research now combines Meets Dog explains the loyalty of facial expressions and other body laboratory experiments, field of a pet dog to its owner in terms language to indicate their mood, are observation, and new technology of canines’ instinctive loyalty toolmakers and users, often behave such as infrared thermography to their pack leader in the wild. cooperatively, and sometimes go to understand insect behavior Tinbergen’s field experiments into battle against rival groups. ■ in ever more detail. showed how gull chicks, which tap

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 102 ILTTAHISASTTTWWHIOELRMLDIHCARVOEBTEHSE MICROBIOLOGY IN CONTEXT M icrobes—bacteria, Scientists did not understand molds, viruses, protozoa, microbes until they could see them. KEY FIGURE and algae—are present The first observations began in the Louis Pasteur (1822–95) in every environment, living in soil, 17th century, using the recently water, and air. Some microbes invented microscope. These BEFORE cause disease but most are vital for studies revealed a previously 1683 Dutch amateur scientist life on Earth. Among other things, unknown world teeming with Antonie van Leeuwenhoek they break down organic matter so microbiotic life. Around the same uses a microscope to observe that it can be recycled back into time, the word “germ,” originally bacteria and protozoa. the ecosystem. meaning “seed,” was first used to describe these tiny organisms. 1796 Edward Jenner carries Trillions of microbes also live on out the first vaccination, using and in the human body. The most Fighting disease the cowpox virus to protect common of these microbes are Some 17th and 18th-century against smallpox. beneficial bacteria, which aid the scientists believed that certain digestion of food, produce vitamins, “germs” might cause diseases, but AFTER and help the immune system find the prevailing view was that such 1926 American microbiologist and attack more harmful microbes. maladies were the spontaneous Thomas Rivers distinguishes result of inherent weakness in an between viruses and bacteria. Microbes are the worker bees organism. It was not until the that perform most of the painstaking laboratory work of the 1928 While studying important functions 19th-century French chemist Louis influenza, Scottish in your body. Pasteur that the “germ theory of bacteriologist Alexander Dr Robynne Chutkan, disease” was proved. Fleming discovers penicillin. Microbiome expert and author Pasteur began by looking at the 2007 An inventory of all alcohol fermentation process. He the microbes associated discovered that sourness in wine with a healthy human body was caused by external agents— is completed. microbes, or germs. A crisis in the French silk industry, caused by an epidemic among silkworms, then allowed Pasteur to isolate and identify the microorganisms that caused the particular disease.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 103 See also: Classification of living things 82–83 ■ The microbiological environment 84–85 ■ The ecosystem 134–137 Where observation animal or human, was particularly Louis Pasteur is concerned, effective at enabling the body’s immune system to fight off the Born in Dole, France, in 1822, chance favors only disease. At first, Pasteur faced Pasteur was the son of a poor the prepared mind. strong opposition and alarm at tanner. He was an average the prospect, but he was able to student, but he worked hard, Louis Pasteur develop vaccines for anthrax, fowl obtaining his degree in 1842 cholera, and rabies—the latter and his doctorate in science As he extended germ theory to involving his first test on a human. in 1847. After teaching in human disease, Pasteur proposed various universities, in 1867 that germs invade the body and Annihilating germs he became Professor of cause specific disorders. Edward The focus later shifted to finding Chemistry at the Sorbonne Jenner, nearly 100 years before, germ-killing agents, or antibiotics, in Paris. His major research had shown that a disease could be such as penicillin—discovered by interest was the fermentation prevented with the application of Alexander Fleming. A strategy of process. Pasteur discovered a “vaccine”—a virus similar to that annihilating microbes has been that the fermentation of wine of the disease-causing microbe. followed ever since. Yet this and beer was caused by Pasteur found that an attenuated, “slash and burn” approach has germs—microbes. He also or weakened, form of a disease- its drawbacks. It kills beneficial discovered that microbes causing germ, produced in a microbes as well as harmful ones, could be killed by short, mild laboratory and injected into the host and also promotes resistance in heat treatment—a process bacteria that can ultimately render now named after him as antibiotics ineffective. ■ “pasteurization.” Pasteur’s “germ theory” led to the wider The bacterium Enterococcus faecalis development of vaccines, is a microbe found in the gut and bowel which remain a vital method of healthy humans. If it spreads to other of disease control. In 1887, areas of the body, however, it can cause he established the Pasteur serious infections. Institute, which opened in 1888 and continues to help prevent and fight diseases. Key works 1870 Studies on Silk Worm Disease 1878 Microbes: Their Role in Fermentation, Putrefaction, and the Contagion 1886 Treatment of Rabies

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 104 HCWAEIVRTETHAAFINUSNYTMGRIEBEIOSSPISECIES THE UBIQUITY OF MYCORRHIZAE IN CONTEXT I n 1885, a professor of plant pathology at the Royal College KEY FIGURE of Agriculture in Berlin named Albert Frank (1839–1900) Albert Frank was the first to see a connection between fungi growing BEFORE on tree roots and the health of the 1840 German botanist trees. Frank realized that these were Theodor Hartig discovers not pathological (disease-related) a network of filaments on the infections but in fact underground roots of pine trees. partnerships: far from suffering, the trees seemed to benefit from better 1874 Hellmuth Bruchmann, nutrition. He invented a new term a German biologist, notes for the partnership—“mycorrhiza,” the “Hartig net” is made of from the Greek mykes, meaning fungal filaments. fungus, and rhiza, meaning root. AFTER Mycorrhizae in action Mycorrhizae on the root of a 1937 A.B. Hatch, an American False truffles are an example of soybean. In arbuscular mycorrhizae, botanist, shows a beneficial the fungal side of this partnership. such as these, the tips of the hyphae relationship between pine Nineteenth-century Prussian form clusters inside the plant’s root trees and mycorrhizal fungus. botanists had found these fungi cells, optimizing nutrient exchange. under spruce trees, and noticed 1950 Swedish botanists Elias that each tree root was drawn absorb the soluble organic Melin and Harald Nilsson toward a truffle, and wrapped in compounds produced through a show that plant roots can a fungal husk. Although they did network of microscopic filaments— extract more nutrients from the not know it, the botanists were hyphae—called a mycelium. soil with the aid of mycorrhizae. witnessing a phenomenon that is vital to many ecosystems. Plants rely on root hairs to 1960 Another Swedish absorb water and minerals, such as botanist, Erik Björkman, shows Fungi are typically nourished nitrates and phosphates. But there is that plants pass carbon into by a supply of organic matter, from a limit to how far plant roots can mycorrhizal fungi in exchange which they extract food by external grow and therefore what quantity of for phosphate and nitrate. digestion. A deep layer of forest nutrients the root hairs can absorb. litter is perfect. They pour digestive The hyphae of mycorrhizae can chemicals onto their meal and cover a much wider area, absorbing

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 105 See also: Evolution by natural selection 24–31 ■ Mutualisms 56–59 Mycorrhizae as ■ The ecosystem 134–137 ■ Energy flow through ecosystems 138–139 pollution indicators Beneficial exchange between Mycorrhizal fungi are not only mycorrhizae and plant roots good for the health of plants— they can also act as indicators Mycorrhiza Supplies sugar from Plant of the health of the entire photosynthesis environment. Laboratory experiments with these fungi Connects plants in an have shown that some grow extensive network badly in the presence of toxins, which means that they can be The mutualistic Increases uptake of used to detect pollutants in relationship between water and nutrients the air or soil. For instance, mycorrhizae and plants some fungi fail to grow when is highly evolved. As Allows plants to share exposed to heavy metals such many as 90 percent of nutrients with others as lead or cadmium, and all plant species rely on because different kinds of fungi for nutrients and Boosts protection fungi react differently to protection. In return, against soil diseases environmental change, certain plants supply the fungi species can be used to identify with a vital food source. specific kinds of pollution. a much greater amount of minerals. fungi in this way. Trees supported Mycorrhizae are also useful When the fungal hyphae attach to by mycorrhizae are more resistant indicators of the health of their the plant roots, they extend the root to drought and disease, and can native habitat. Many form system, causing extra nutrients to even communicate alarm signals by cauliflower-like growths seep into the plant. releasing chemicals in response to on tree roots, but these are attack by herbivores. This fungal smaller in polluted soil. The Albert Frank realized that this network connecting trees has been trees themselves may also partnership worked both ways. It dubbed “the wood-wide web.” ■ respond to pollution with was a winning combination for both weaker shoot growth, but plant and fungus. In exchange for [the fungus] performs the mycorrhizal response is passing on a share of its minerals, a “wet nurse” function more acute and serves as a the fungus receives sugar from the valuable early-warning sign plant—made by photosynthesis in and performs the of a habitat in decline. the leaves and transported to the entire nourishment roots via the plant’s sap. This boosts Weak growth in the russet the nutrient supply that the fungus of the tree from brittlegill, a mycorrhizal fungus derives from dead organic matter. the soil. of European and North American spruce forests, can be an early Ancient networks Albert Frank indicator of habitat air pollution. Fossils of plants dating from 400 million years ago—when vegetation was first spreading across dry land—show traces of fungal threads. This suggests that the mycorrhizal partnership was key to the evolution of terrestrial life. Today, the majority of plant species continue to rely on

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РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 108 ANIMAL ECOLOGY IN CONTEXT The concept of food chains— knowledge of individual plant and the idea that all living animal species to the cells in a KEY FIGURES things are linked through beehive—each “cell” of knowledge Charles Elton (1900–91), their dependence on other species is important in its own right, but George Evelyn Hutchinson for their food—dates back many by putting them all together (1903–91) centuries, but it was not until the something much more than the early 20th century that scientists sum of the parts is created— BEFORE developed the concept of food the “beehive” of ecology. Ninth century Arab writer chains forming a food web. Al-Jaziz introduces the Nowadays, the study of animal concept of the food chain The pioneer of this thinking was ecology focuses on how animals in Kitab al-Hayawan (Book British zoologist Charles Elton, interact with their environment, of Animals), concluding that whose book Animal Ecology (1927) the roles played by different “every weak animal devours describes what he called the “food species, why populations rise those weaker than itself”. cycle”. He later went on to develop and fall, why animal behaviour theories that encompassed more sometimes changes, and the 1917 American biologist complex interactions between impact of environmental change on Joseph Grinnell first describes animals and the environment— animals. The principle underlying an ecological niche in his insights that underpin modern the work of animal ecologists is paper, “The niche relationships animal ecology. He likened our that there is generally a balance of the California Thrasher.” Food web AFTER 1960 American ecologist and Whale Albatross philosopher Garrett Hardin Arrow worm publishes an essay in the Krill Schooling fish Leopard magazine Science in which Phytoplankton seal he states that “every instance of apparent coexistence must Blue-green Radiolarians be accounted for.” bacteria 1973 Australian ecologist Penguin Robert May publishes Stability and Complexity in Model Ecosystems, in which he uses mathematical modeling to demonstrate that complex ecosystems do not necessarily lead to stability. Copepod Dolphin Marine worm Squid A food web is a graphic depiction Killer whale of the feeding connections between different species within an ecological Seaweed Bottom-feeding community. This example illustrates fish the relationships within a marine ecosystem, in which killer whales are the apex predators and phytoplankton are the primary producers.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 109 See also: Keystone species 60–65 ■ The food chain 132–133 ■ The ecosystem Forecasting the effects 134–137 ■ Energy flow through ecosystems 138–139 ■ Trophic cascades 140–143 of climate change in nature, so if the population Ecologists examine changes of a given species grows too large to animal populations and it will be regulated, most often by a distribution and apply climate lack of food. However, relationships change models to forecast how between organisms and their these will change further in environment change from place the future, over the course of to place and through time. 5, 10, 50, or more years. In the Arctic, for example, where Chain of dependence A spider traps a damselfly, average temperatures are In Animal Ecology, Elton outlined demonstrating that the principle rising more rapidly than the key principles of the study of of food size can be modified by the anywhere else, the sea ice is animal communities: food chains comparative aggression and strength contracting. As a result, polar and webs, food size, and ecological of the predator and its prey. bears have to travel farther in niches. Each food chain and web, search of ice where they can he asserted, is dependent on against rivals of their own species catch seals, rest, and mate. producers: plants and algae that to ensure there is enough food for The farther they swim, the support plant-eating consumers themselves and their offspring. more energy they burn. As (herbivores). These herbivores in the sea ice declines, the polar turn support one or more levels of Food size bears starve. Scientists meat-eating consumers (carnivores). One of Elton’s most important monitor their numbers and Large carnivores generally eat points was the notion that food movements and compare this smaller animals, but because small chains exist primarily because data with changes in sea ice. animals reproduce more quickly, of the principle of food size. He their numbers are able to support explained that every carnivorous The polar bear plays a the larger predators. animal eats prey between upper vital part in the ecology of the and lower limits. Predators are Arctic. As an apex predator Competition for food is very tight physically unable to catch and and keystone species, it must near the top of a food web. Although consume other animals above a have access to seals, which apex (top) predators, such as big certain size because they are not are its almost exclusive diet. cats and large birds of prey, have no large enough, strong enough, or The number of seals regulates natural predators, this often means skillful enough. That is not to say the density of polar bears, that they have to defend territories that predators cannot kill and eat while polar bear predation in larger animals than themselves; a turn regulates the density and Every animal is closely weasel can easily kill a larger rabbit reproductive success of seals. linked with a number of because it is more aggressive. However, an adult lioness, one A lone polar bear surveys the other animals living of the world’s top predators, is not sea for prey from a piece of floating around it—and these are capable of killing a healthy adult ice in the Arctic. The shrinking African elephant. Likewise, area of sea ice in the region largely food relations. a dragonfly larva on the bottom threatens this species’ survival. Charles Elton of a pond may be able to prey on a small tadpole, but it would not be able to eat an adult frog. ❯❯

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 110 ANIMAL ECOLOGY Snowshoe hare and The Sword-billed Hummingbird, lynx population cycles a native of South America, has a long bill, which enables it to suck up nectar In Canada’s boreal forests, from the long flowers of Passiflora the favored prey of lynx are mixta, a species of passionflower. As snowshoe hares. Charles Elton it feeds, it spreads the plant’s pollen. examined the relationship between the populations Animals may be capable of killing working in the early decades of the of these two species, using much smaller prey, but it is simply 20th century, an organism’s niche data covering the period not worth the effort. Wolves hunt was defined as its habitat. He 1845–1925. When hares are medium-sized or large mammals studied birds called thrashers in numerous, lynx hunt little such as elk. If those mammals California and observed how they else. After their population disappear from their environment, fed, nested, and hid from predators reaches its peak density, they find it hard to catch sufficient in the dense undergrowth of the the hares struggle to find numbers of smaller animals such chaparral shrubland. However, a enough plant food. Some as mice to sustain them; the niche is more complex than simply starve, while others are energy they use finding small prey the place where an organism lives. weakened and are more is greater than the energy they Oxpeckers and buffalo share exactly easily caught by predators, gain by consuming them. the same habitat—open grassland – including lynx, which feed but their requirements for survival very well for a time. When Plants cannot run away or fight are very different: the buffalo graze hare numbers continue to back, so different considerations on the grasses, while oxpeckers fall, this affects the lynx. apply to herbivores when it comes derive their food from the ticks they They are forced to hunt to food size. There is a maximum peck from the buffalos’ hide. less nutritious prey, such size of seed that a given finch, as mice and grouse. for example, can fit in its bill, so Charles Elton explored the larger finches have an advantage concept of ecological niches in As they struggle to find over smaller species. Similarly, more depth. For him, food was enough to eat, lynx produce individual species of hummingbirds the primary factor in defining an smaller litters or even stop can drink nectar only from flowers animal’s niche. What it ate and breeding altogether. Some up to a certain size, depending what it was eaten by were crucial. starve to death. A decline in on the length of their bill. Depending on the habitat, a the lynx population sets particular niche could be filled by in one or two years after the a different animal. Elton cited the hare population has bottomed example of a niche that was filled out, a cycle that repeats every eight to eleven years. Observation of species in the wild convinces me that the existence and persistence of species is vitally bound up with environment. Joseph Grinnell A Canadian lynx captures a Ecological niches snowshoe hare, its preferred prey. An animal or plant’s niche is its When hares are plentiful, a lynx ecological role or way of life. For will eat two every three days. American zoologist Joseph Grinnell,

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 111 Different species press interacts with other organisms and example, koalas depend almost against one another, like with its environment. For example, entirely on eucalyptus leaves, and soap bubbles, crowding each species of trout—and other Hyacinth Macaws in the Pantanal fish—has its own range of water region of Brazil eat virtually nothing and jostling, as one salinity, acidity, and temperature but the hard fruits of two species of species acquires … some that it can tolerate, as well as a palm trees—these are specialists. advantage over another. range of prey and river- or lake-bed G. Evelyn Hutchinson conditions. This makes some better Animals rarely occupy the whole competitors than others, depending of their niche width, owing to by birds of prey that hunted small on the conditions of the habitat in competition between species. Part ground-dwelling animals such as which they live. Seen as the father of the habitat requirement of North mice and voles. In a European of modern ecology, Hutchinson American bluebirds is dead trees oakwood, that niche would be filled inspired other scientists to explore with old woodpecker holes in which by Tawny Owls, while on open how competing animals use their they lay their eggs and raise their grassland Kestrels would fill the role. environment in different ways. young. Although suitable holes are common in many forests, bluebirds Elton also argued that an animal An animal or plant’s niche cannot occupy all these holes could not only tolerate a certain set width comprises the whole range because they are often out- of environmental conditions, but of factors it requires to allow it to competed by more aggressive could also change them. The tree- thrive. Brown rats, raccoons, and starlings. Therefore their realized felling and stream-damming starlings are examples of animals niche—the places they actually activity of beavers is one of the with a broad niche width in that occupy—is not as extensive as their most dramatic examples, creating they are able to survive in a wide potential (or fundamental) niche. habitats for fish in dammed pools, variety of conditions. Such species woodpeckers in dead trees, and are called generalists. Other animals Many animals share some dragonflies around pool margins. have narrow requirements. For aspects of their niche, but not others. This is called niche ❯❯ Niches and competition British-born zoologist G. Evelyn Hutchinson, working at Yale University from the 1950s to the 1970s, examined all the physical, chemical, and geological processes at work in ecosystems and proposed that any organism’s role in its niche includes how it feeds, reproduces, finds shelter, and A true specialist, a koala bear requires 2.5 lb (1kg) of eucalyptus leaves a day. This species is found in the wild only in Australia, where eucalyptus is common.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 112 ANIMAL ECOLOGY Three major overlap. If different species live in types of ecological the same habitat and have similar lifestyles, they will be in pyramid competition but they may be able to live in close proximity if some Pyramid 1 aspects of their behavior or diet The basic process in of numbers Osprey differ. This arrangement is known trophic dynamics is the as niche partitioning. For example, transfer of energy from 10 various anole lizards on Puerto one part of the ecosystem Northern pike Rico successfully occupy the same areas because they select perching to another. 100 locations in different parts of trees. Raymond Lindeman Perch There are limits to niche numbers to produce a pyramid 1,000 overlap. When two animals with of biomass that represented the Bleak identical niches live in the same amount of living matter in a given place, one will drive the other area at every level. This took 10,000 to extinction. This concept—the into account the fact that some Freshwater shrimp competitive exclusion principle— organisms are much larger than was outlined by Joseph Grinnell others, but because it showed Pyramid Wolf in 1904 and developed in a paper comparative biomasses at a fixed of biomass 340 lb published by Russian ecologist point in time, it produced anomalies. per sq mile Georgy Gause in 1934, becoming For example, in a pond, the mass Red fox known as Gause’s law. of the phytoplankton producer 1,700 lb (microscopic organisms that are the per sq mile Pyramid of numbers foundation of the aquatic food web) Charles Elton used a pyramid as may not be as great as the mass of Snowshoe hare a way of graphically representing the fish consumers at a particular 17,000 lb per sq mile the different levels in a food chain, point in time, so the pyramid with the producers at the bottom, will be inverted. However, Grass the primary consumers on the phytoplankton reproduce quickly 18 million lb per sq mile level above, and so on. Often, the primary consumers—insects, Pyramid Apex in particular—will outnumber the of energy predators producers, but the higher levels of consumers will become less 0.01% numerous toward the top of the Secondary pyramid. This system does not carnivores take account of parasites; fleas and ticks on mammals and birds 0.1% will far outnumber the total of all Carnivores the vertebrates in an ecosystem. 1% In 1938, German-born animal ecologist Frederick Bodenheimer Herbivores modified Elton’s pyramid of 10% Producers 100% Ecological pyramids represent Microscopic organisms, including quantifiable data in an ecosystem. these diatoms, form a significant part Numbers show the population size of of all ecological pyramids. Their huge individual species in a trophic level; numbers and rapid reproduction biomass, their relative presence; and provide mass and energy for the energy, who eats what and how much. species higher up the pyramid.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 113 when conditions, such as sunlight herbivore, some of the energy Tench feed on snails, which graze and nutrients, are right. Over time, transfers to the animal. When on periphyton—a mixture of microbial the mass of the phytoplankton will a predator eats the herbivore, organisms that cling to plants. By far outweigh that of the fish. it receives a smaller amount of that reducing the number of snails, tench energy, and so on. increase the periphyton biomass. Trophic pyramids American ecologist Raymond Published in 1942, Lindeman’s above. Assessing energy transfer, Lindeman proposed a pyramid of Ten Percent Law explains that however, requires a lot of information energy, called the trophic pyramid, when organisms are consumed, about energy intake, as well as the showing the rate at which energy only about 10 percent of the energy number and mass of organisms. is transferred from one level to the transferred from them is stored as next as herbivores eat plants, and flesh at the next trophic level. The Future thinking predators eat herbivores. An energy model creates a more Relationships between organisms organism’s trophic level is the realistic picture of the condition and their environment change position it occupies in a food chain. of an ecosystem. For example, if from place to place and through Plants and algae are at trophic level the biomass of weed and fish in time. Global climate change is one 1, herbivores at level 2, and the first a pond is the same, but the weed example of environmental factors level of predators is at 3. It is rare reproduces twice as fast as the fish, that will increasingly affect animal for there to be more than five levels. the energy of the weed would be communities. Some changes have Plants convert the sun’s energy shown to be twice as large. Also, already taken place, but one of the into stored carbon compounds, there are no inverted pyramids— challenges of ecological thinking and when a plant is eaten by a there is always more energy in the in the future is to forecast others. ■ lowest trophic level than the one

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 114 BOOTHIFFREEODGOFSGFPLSSTAPIMTYRHUITNAMHTGENPNURUMOMDBBUEECRRE CLUTCH CONTROL IN CONTEXT W hy do some birds lay eggs are removed from a nest; the more eggs than others? bird will re-lay repeatedly to KEY FIGURE For example, Blue Tits compensate for the loss. David Lack (1910–73) lay nine eggs, Northern Flickers six, and Robins four. In the 1940s, Instead, Lack said, the number BEFORE British ornithologist and evolutionary of eggs laid by any species has 1930 British geneticist ecologist David Lack proposed an evolved to fit with the food supply Ronald Fisher combines explanation that rapidly gained available. In other words, nature Gregor Mendel’s work on support. He argued that the clutch favors clutch sizes that correspond genetics with Charles size (number of eggs laid) was not to the maximum number of young Darwin’s theory of natural controlled by the female’s ability to selection, and argues that the lay eggs, since birds can lay many Blue Tit nests contain an average of effort spent on reproduction more eggs than they typically do. nine eggs, although the females can lay must be worth the cost. This fact can be demonstrated by many more. David Lack proposed that replacement experiments, in which the clutch size is determined by the AFTER likely amount of available food. 1948 David Lack extends his theory of optimal clutch size in birds to include litter size in mammals. 1954 Lack develops his food limitation hypothesis further in The Natural Regulation of Animal Numbers, to encompass birds, mammals, and some insect species. 1982 Tore Slagsvold proposes the nest predation hypothesis, which states that clutch size is related to the likelihood of the nest being attacked.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 115 See also: Animal ecology 106–113 ■ Animal behavior 116–117 ■ The food chain Siblicide and the 132–133 ■ The ecosystem 134–137 ■ Ecological resilience 150–151 Blue-footed Booby that the parents are likely to be able Laying a clutch which Blue-footed Boobies are to sustain. So, if a pair of birds can will result in a smaller seabirds native to the Pacific only find enough food to feed six brood than … could be fed Ocean. They get their food chicks, but the female has laid 12 and reared successfully … from the ocean, but come eggs, those young will be hungry confers advantages. to rocky shores and cliffs to and may starve. If she has laid just breed. The female lays two one egg, although the chick will Tore Slagsvold eggs, roughly five days be raised successfully, most of apart, so that by the time the the available food will have been of food during the long day-length second chick hatches, the first unused. So neither the 12-egg nor of summer compared with the one has already grown the one-egg scenarios are good shorter day-length in the tropics. considerably. When food is reproductive strategies; instead, plentiful, the parents can find laying six eggs offers the best However, other factors may enough to feed both offspring chance of raising the most offspring. also apply. Higher mortality rates until they fly the nest (fledge). in high latitudes—where winters However, when food is scarce, This theory became known as are harsh—may have led to the the larger chick will peck its the food limitation hypothesis, or evolution of large clutch sizes. This junior sibling to death. The Lack’s principle, and it was later is because the chances of survival older chick can then get more generalized by him and others to until the next breeding season food, and is more likely to cover litter size in mammals and are low, and the reduced population fledge. If it does not murder clutch size in fish and invertebrates. results in more food being available its sibling when food is scarce, for the survivors next season. both chicks may starve. The “latitude trend” Lack’s hypothesis also suggested In 1982, Tore Slagsvold, a This behavior, based an answer to another puzzle: why Norwegian evolutionary ecologist, exclusively on the availability most bird species have bigger advanced the nest predation of food, is called “facultative clutches at higher latitudes. On hypothesis, which proposes that siblicide.” In contrast, masked average, birds near the equator lay high rates of nest predation result boobies practice “obligate about half the number of eggs laid in smaller clutches. If a nest with siblicide”—the first-hatched by the same species in the far many chicks is found by a predator, chick nearly always kills its north. This “latitude trend” could be more work by the parent birds will brother or sister, regardless explained by a greater availability have been wasted than if the nest of how much food is available. contained fewer chicks. Also, Clutch size increases parents raising a large clutch are Blue-footed Boobies are driven with increasing latitude more likely to be seen by predators, to siblicide by genetic factors. and day length because … because of the extra activity. Some The murder of a sibling can benefit a longer day enables the ecologists have argued that the the perpetrator while also ensuring parents to find more food. relative abundance of predators in the survival of the entire species. the tropics has been more important David Lack than food supply in the evolution of small clutch sizes at low latitudes. ■

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 116 DCTTHHOANEEG TBEISIOVEENASRSDOBLWFEAITSTHTHIISNAGETARARUSTEH ANIMAL BEHAVIOR IN CONTEXT A ny dog owner will describe Ducklings imprinting is an example the companionable and of instinctive behavior that can be KEY FIGURES loyal relationship they manipulated—to make them imprint Konrad Lorenz (1903–89), enjoy with their pet. The Austrian on humans or even inanimate objects. Nikolaas Tinbergen zoologist Konrad Lorenz set out (1907–88) to explain this behavior in Man when devising rigorous field Meets Dog (1949). He described the experiments that could be repeated, BEFORE behavior of dogs and other pets as so that the findings could be 1872 Charles Darwin’s The substantially innate, “instinctive recognized as facts, not anecdotes. Expression of the Emotions in activity,” as opposed to behavior Man and Animals posits that learned through conditioning. The term “ethology” was coined behavior is instinctive and has Lorenz proposed that such hard- by American entomologist William a genetic basis. wired behavior helped the animal Morton Wheeler in 1902 to describe survive as a species. For example, a the scientific study of animal 1951 Nikolaas Tinbergen’s domestic dog’s loyalty to its human behavior. Ethologists study animals The Study of Instinct lays master originates in the natural in their natural habitats, combining down the foundations and behavior of its wild ancestors, laboratory studies and fieldwork theory behind ethology, the which were loyal to the pack leader in order to describe an animal’s study of animal behavior. because this had benefits in terms behavior in relation to its ecology, of hunting success and safety. evolution, and genetics. AFTER 1967 Desmond Morris, Field experiments Ethologists found that in certain a British zoologist, brings Lorenz was not alone in his theories. situations, an animal will have a ethology to bear on human Other biologists working in the field predictable behavioral response. behavior in his popular book included fellow Austrian Karl von They called this a “fixed action The Naked Ape. Frisch and Dutch biologist Nikolaas Tinbergen, who studied animals 1976 British evolutionary in their natural environments. Until biologist Richard Dawkins then, most animal behavior studies publishes The Selfish Gene, had taken place in laboratories or describing how most of an artificial settings, so the behavior animal’s behavior is designed witnessed was not entirely natural. to pass on its genes. Studying animals in the wild had its own challenges, particularly

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 117 See also: The selfish gene 38–39 ■ Field experiments 54–55 ■ Keystone species 60–65 ■ Animal ecology 106–113 ■ Clutch control 114–115 ■ Using animal models to understand human behavior 118–125 ■ Thermoregulation in insects 126–127 pattern” (FAP). A FAP has set Four elements of ethological experimentation characteristics. It is species- specific; it is repeated in the same Causation Development way every time and is not affected What triggered What stage is the animal by experience. The triggers for the the behavior in in its life cycle, and does the behavior (“sign stimuli”) are highly the first place? specific and may involve a color, behavior change as pattern, or sound. For example, male the animal develops? sticklebacks respond aggressively when another male enters their When studying streambed patch. Ethologists animal behavior, suggest this is triggered by seeing scientists consider the male’s red underbelly. these four elements Nikolaas Tinbergen found Evolution Function that some an artificial sign stimuli How is the behavior How does the behavior work better than the real thing. He related to the animal’s increase the animal’s investigated the begging behavior evolution or ancestry? of herring gull chicks, which peck chance of survival or at a red spot on the parent gull’s reproductive success? beak to make it regurgitate food. He found that chicks will also peck at a model of the gull’s beak, yet when they were offered a narrow red pencil with three white lines at the end, the chicks pecked at this even more enthusiastically. Tinbergen called this a “supernormal stimulus,” showing that instinctive animal behavior can be manipulated artificially. ■ Konrad Lorenz Born in Vienna, Austria, Lorenz and other birds, as well as was enthralled by animals from mammals, is instinctive and an early age and kept fish, birds, occurs shortly after birth. Lorenz cats, and dogs. The son of an demonstrated the theory by orthopedic surgeon, he studied quacking like a duck at newly medicine at Vienna University, hatched ducklings. He soon graduating in 1928, and gained had a flock of ducklings that his Ph.D. in zoology in 1933. His followed him everywhere. numerous pets became the first subjects of his studies. Lorenz is Key works perhaps best known for describing the phenomenon known as 1952 King Solomon’s Ring: “imprinting.” This is when a New Light on Animal Ways newly hatched chick bonds with 1949 Man Meets Dog the first thing it sees (usually its 1963 On Aggression parent) and will follow it around. 1981 The Foundations for The behavior, seen in ducks Ethology

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS REDEFINE “TOOL,” AS HUMANSCHIMPANZEESREDEFINE “MAN,” OR ACCEPT USING ANIMAL MODELS TO UNDERSTAND HUMAN BEHAVIOR

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РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 120 USING ANIMAL MODELS TO UNDERSTAND HUMAN BEHAVIOR IN CONTEXT The Primates Tree KEY FIGURE 750,000–550,000 ya Humans and their Jane Goodall (1934–) 6 mya closest relatives, BEFORE chimpanzees, are both 1758 Carl Linnaeus, the father primates. This shows of taxonomy, dares to classify how primates have humans within the rest of evolved over the last nature, calling us Homo 66 million years. sapiens (“wise man”). 1859 Charles Darwin’s 35 mya Great theory of evolution further 40 mya apes challenges the established Lesser view that man is different apes from the animal kingdom. Old world AFTER monkeys 1963 Konrad Lorenz publishes New world On Aggression, proposing monkeys that warlike behavior in humans is innate. Primates 1967 Desmond Morris, a British zoologist and 65 mya ethologist, publishes The Naked Ape: A Zoologist’s Modern Neanderthal Gorilla Chimpanzee/ Orangutan Study of the Human Animal, human Bonobo a major study that describes human behavior in the Gibbon Monkey Baboon Tarsier Lemur Loris context of the animal kingdom. M odern molecular studies scientific community remained In reality, we are Pan narrans, mapping the genomes convinced that humankind was the storytelling chimpanzee. of humans and other different from the rest of nature. animals have confirmed a theory Terry Pratchett that was first suggested by Charles It was largely the work of British Darwin in the mid-19th century— primatologist Jane Goodall that British fantasy author that we share a common ancestor opened our eyes to the similarities with the great apes. Today, few between chimps and man. In 1961, scientists would dispute that the in an excited communication common chimpanzee (Pan to her mentor, Louis Leakey, troglodytes) and the bonobo or Goodall announced an observation pygmy chimpanzee (Pan paniscus) that would shake the scientific are our closest living relatives. The establishment: she had seen study of these animals therefore a chimp using a tool. It was the offers us a unique chance to learn first time this behavior had about ourselves and the origins of been documented and it would our behavior. Yet for many years the challenge perceived ideas of what it means to be human.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 121 See also: Evolution by natural selection 24–31 ■ A system for identifying all nature’s organisms 86–87 ■ Animal ecology 106–113 ■ Animal behavior 116–117 Goodall’s knowledge of natural history had impressed Leakey on their first meeting in 1957 and he offered her a job studying the behavior of chimpanzees. As an anthropologist and paleontologist, Leakey believed in evolutionary theory, which proposed that humans and the great apes—chimpanzees, bonobos, gorillas, and orangutans— in the family Hominidae (Great Apes), share a common ancestor. Making connections Until this point, the scientific and A chimp uses a twig stripped of its Leakey’s fieldwork focused on popular consensus was that the leaves—a modified “tool”—to catch looking for the “missing link”— ability to devise and make tools termites for consumption. Goodall first fossils of transitional forms marked humans out as superior recorded the ability of chimpanzees to between that common ancestor to the rest of the animal kingdom. invent simple technologies in Gombe. and humans. Chimpanzees had not Goodall’s findings forced scientists been studied seriously in the wild to think again. true unfettered behavior, Goodall and such a study, he reasoned, was one of the first people to work could throw light on the evolution Goodall’s camp was in Gombe in the field of ethology, whereby of early humans. Goodall, a keen Stream National Park, Tanzania, biologists monitor animals in their observer and free of academic ties, where she studied a chimp natural environments and try to was the ideal choice for the work. community on the eastern shore understand their natural behaviors. As Leakey had hoped, she provided of Lake Tanganyika. In choosing to In her first few months at the ❯❯ a fresh perspective on the theory live among chimps to witness their and was brave enough to say that chimps and humans were more alike than had been imagined. Jane Goodall Born in London in 1934, Jane transformed our understanding Goodall’s first meeting with a of chimpanzees and challenged chimp was a stuffed animal that perceived ideas of our own place her father named Jubilee. She was in the natural world. In 1965, she interested in animal behavior from earned a Ph.D. in ethology from an early age—once, she hid in a Cambridge University. Her many henhouse for hours so that awards include France’s Legion she could watch a chicken lay of Honor, given to her in 2006. an egg. She left school at 18 and worked in various jobs, before Key works going to Kenya in 1957 and meeting paleoanthropologist 1969 My Friends the Wild Louis Leakey. With his support, Chimpanzees in 1960 Goodall set up a research 1986 The Chimpanzees of base in Gombe, Tanzania, where Gombe: Patterns of Behavior she was to study chimpanzees 2009 Hope for Animals and until 1975. Her work radically Their World

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 122 USING ANIMAL MODELS TO UNDERSTAND HUMAN BEHAVIOR camp, the chimps fled from her, and then using them in termite Jane Goodall working, notebook in but they then began to forget she mounds; the chimps were not only hand, at Gombe National Park in 2006. was there. using tools but making them. The pioneering primatologist continues her lifelong commitment to protect Goodall sat for many hours Chimp technology endangered chimpanzees. observing the chimps, keeping her Goodall went on to witness nine distance and quietly making field different tools being used by instead of numbers, suggesting notes. One morning in November chimps in the Gombe community. that her fieldwork was less than 1961, she noticed a chimpanzee she At the time, scientists questioned rigorous. Since then, however, many called David Greybeard sitting over Goodall’s methods and ridiculed other studies around the world have a termite mound. He was poking her for giving the chimps names corroborated her findings: chimps in blades of grass into the mound, the Congo have been observed pulling them out, and then putting I viewed my stripping twigs to use in termite them into his mouth. She watched fellow man not mounds; chimps in Gabon have for some time before the chimp as a fallen angel, been seen heading into the forest moved off. On reaching the spot but as a risen ape. with a five-piece “toolkit” that where the chimp had been sitting, Desmond Morris included a heavy stick for opening Goodall saw discarded grass stems bee hives and pieces of bark for lying on the ground. Picking one up British Zoologist scooping up the honey. In Senegal, and poking it into the mound, she hunting parties of chimps have been found that the agitated termites bit observed traveling with sticks that onto the stem. She realized the they chew to a sharp point and use chimp had been “fishing” for like spears to kill bush babies. termites with the grass stems, and transferring them into his mouth. More alike than different Ethologists take behaviors studied From talks with Leakey, Goodall across several species to formulate knew this was a major discovery. generalizations that apply to many She also saw chimps modifying thin twigs by stripping them of leaves

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 123 We admit that we it is worth noting that these Chromosomal are like apes, but percentages are based on genes evidence we seldom realize that instruct the body how to make that we are apes. proteins, which make up a very A strong piece of evidence Richard Dawkins small part of the human genome in favor of a shared common (about 2 percent). It is likely that the ancestor is seen by comparing British evolutionary biologist things that make humans different chromosomes. Chimpanzees from chimpanzees can be found in (and gorillas) have 24 pairs of species. The idea that animal the regions of DNA called “junk chromosomes. Humans have behavior could be a model for DNA” because they were previously only 23. Evolutionary scientists human behavior took root in the thought to be redundant. It is now believe that when we diverged work of ethologists in the 1950s and understood that this junk DNA from a common ancestor, two ’60s, such as Konrad Lorenz, holds vital information about how chromosomes in humans Nikolaas Tinbergen, and Karl von and when genes are expressed. fused and this is why we have Frisch. Studying animals in their Still, the similarities between the one less pair than other apes. natural habitats, they saw how DNA of humans and the great apes complex the lives of animals were. are striking. On the ends of every They began to understand social chromosome, there are genetic interactions arising from instinct Meat-eating hunters markers—or sequences of as well as learned behaviors. The During her studies, Goodall also DNA—called telomeres. In the animal studies held a mirror up witnessed chimps eating meat middle of each chromosome to human behaviors. and hunting. As with tool-making, there is a different sequence, the idea that chimpanzees were known as a centromere. If The persistent belief that carnivorous predators went against two chromosomes have fused, humans are totally different from all received knowledge. At first, it should be possible to see other species was firmly rebutted scientists claimed it was aberrant telomere-like regions in the with the advent of gene mapping. behavior, but as the research middle of the chromosome as When the chimpanzee genome was continued and more sightings were well as at each end. Also, the mapped in 2005—followed by the made, it became established fact. fused chromosome would have other great apes—and compared Meat-eating has been reported in two centromeres. Scientists with the human genome, the just about every area where chimps looked and found just this. results were clear. Humans share have been studied, from Gombe Human chromosome 2 appears 98.8 percent of their DNA with and Mahale Mountains National to be the fusion of chimp chimps, 98.4 percent with gorillas, Park, Tanzania, to Tai National chromosomes 2a and 2b. It is and 97 percent with orangutans. Park, in Côte d’Ivoire. ❯❯ almost beyond doubt that we Humans and great apes are more share a common ancestor with alike than they are different. Yet chimps, bonobos, and gorillas. An alpha male’s body language says “keep away” to begging chimps wanting a share of his prey in Gombe National Park. The main source of prey for chimps is the colobus monkey.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 124 USING ANIMAL MODELS TO UNDERSTAND HUMAN BEHAVIOR Conservation of chimpanzees Orphaned chimps—their mothers According to the Jane Goodall chimp communities when roads killed for bushmeat—walk along a Institute in Tanzania, the number are built through their territories. mud track with their keeper at a of chimpanzees living in the wild Roads also encourage another conservation center in West Africa. has plummeted over the last damaging activity—hunting century. In 1900, there were an for bushmeat, a highly valued estimated 1 million chimpanzees meat in Africa that includes in Africa; today, there are fewer great apes. Roads enable than 300,000. Habitat loss due to hunters from towns to travel a rising human population in need directly into the bush. The of more space has had a huge protection of chimps focuses impact, as have industries such on land conservation and on as logging and mining, which raising awareness both locally destroy habitat and fragment and across the globe. Such behavior has implications Although chimps sometimes hunt for the war was unclear; some for human evolution. Science has alone, hunting tends to be a group researchers blamed the feeding long questioned why and when activity. Chimps rampage through stations Goodall had set up in the humans first began eating meat. the forest, coordinating their area, which may have encouraged From prehistoric stone tools and positions and surrounding their unnatural congregations of chimps. marks on bones, paleontologists prey. After the hunt, the food is The answer to the mystery came know that the early hominids shared. This shows how early in March 2018, when a research were using stone tools to cut meat ancestors of humans may have team at Duke and Arizona State from animals bones 2.5 million developed cooperative behavior, Universities, US, digitized Goodall’s years ago, but it is not known a factor that may have contributed meticulous check sheets and field what they were eating between to their evolutionary success. notes from 1967 to 1972 and fed then and 7 million years ago, them into a computer in order to when the common ancestor Chimp warfare analyze the social networks and of chimpanzees and humans A shocking revelation that came alliances of all the male chimps. is thought to have lived. out of the Gombe camp was that Their findings revealed that the chimps are capable of violence, fracture in the community occurred It is likely that these early murder, and in particular warfare— two years before the war broke hominids hunted prey. Although once believed to be the preserve out, when an alpha male Goodall they did not have large canine of humans. Between 1974 and 1978, called Humphrey took over the teeth like chimpanzees, these are Jane Goodall watched as her troupe, alienating two other high- not necessary for hunting and peaceful community of chimps killing small prey. Biologists have fractured into two rival groups that observed that chimps hunting then waged savage war on each colobus monkeys grab them from other. Goodall was deeply upset the trees and then kill them by about the chimps’ activity, which repeatedly thumping the bodies included ambushes, kidnappings, on the ground; early hominids and bloody murder. The trigger could have hunted and killed in a similar fashion long before Chimps may fight over territory the earliest known tools. in order to acquire more resources or mates, but some primatologists Cooperative behavior maintains that such aggression is Another aspect of chimps’ hunting unnatural and provoked by human behavior that is similar to that impact on their habitat. of humans is the social element.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 125 I’m determined my associated with food resources and piece of fruit hanging over one room great grandchildren meat eating. When food is limited, (B). The bonobo in room A could the chimps become more violent release the fruit but not get to it will be able to in order to obtain the resources himself. The researchers found that go to Africa and they need. Chimps are known to this bonobo would consistently find wild great apes. eat more meat when fruit is scarce. release the fruit, so that the other Jane Goodall one could reach it, helping a Kissing cousins stranger, with no reward for himself. ranking males called Charlie and The link between food scarcity Hugh and causing them to split and aggression in the common Researchers also observed how off with some other chimps to the chimpanzee may explain why our the sight of an unknown bonobo south. The two groups became other evolutionary cousin in the yawning in a film would trigger more and more separate, feeding primate world, the bonobo (pygmy a yawning response in bonobos in different parts of the forest. At chimp), is so peace-loving. These watching the film, suggesting a first there was the odd aggressive small, placid chimps are omnivores capacity for empathy. Other studies skirmish and then war broke out. but live in an environment where have shown how bonobos comfort Over four years, Humphrey and his fruit is plentiful most of the time. each other when in distress. Unlike cohorts killed every male in the They forage in groups, and tend the “negative” behavior that southern group and took over their to use sex to relieve tensions in humans share with chimps, territory, as well as three surviving social situations. Conflict is rare these traits mirror more laudable females. It is thought that the full- in bonobo societies, which are human characteristics, such as blown war may have been due also matriarchal, unlike the male- compassion. Understanding such to a lack of mature females in the dominated chimp communities. behavior in bonobos could shed northern group. Power struggles light on how our human social and fighting over a female all sound An experiment carried out by behavior developed. ■ very human. researchers at Duke University, North Carolina, in 2017 showed Bonobos are very social primates. that bonobos are also altruistic. Two Their capacity for empathy makes bonobos (unknown to each other) them less aggressive and may align were put in adjacent rooms (A and B) them more closely with their human with a fence between them and a cousins than the common chimpanzee. Fights over resources The long-running war witnessed by Goodall is the only sustained conflict among chimpanzees to have been fully documented, but violence within chimp communities has been recorded many times. Chimps have been observed stealing and killing baby chimps and rounding on a disliked alpha male. In communities studied in Uganda, males routinely beat the females they mate with. It is thought that this violent streak running through chimps may be

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 126 DTAEELMPLEPBNEODRDSAILTOYUNRAECTIVITY THERMOREGULATION IN INSECTS IN CONTEXT Insects are usually described as known that many insects are “cold-blooded,” or ectotherms. heterotherms, maintaining different KEY FIGURE Unlike mammals and other temperatures in different parts of the Bernd Heinrich (1940–) “warm-blooded” endotherms, body, and are sometimes far warmer animals that maintain their body than the ambient temperature. BEFORE temperature at a more or less 1837 In the UK, George constant level, insects have a The right temperature Newport observes that flying variable body temperature that The main challenge facing insects insects are capable of raising changes with their environment. is how to get warm enough to fly their body temperature above but cool enough not to overheat. the ambient temperature. In the early 19th century, German–American entomologist however, British entomologist Bernd Heinrich explained in 1974 1941 Danish researchers George Newport discovered that how moths, bees, and beetles could August Krogh and Eric some moths and bees raise the continue to function by controlling Zeuthen conclude that the temperature of their thorax (the their own temperature. He realized temperature of an insect’s central part of the body, to which that insects’ thermal adaptations flight muscles just before wings and limbs attach) above that do not differ as much from those of takeoff determine the muscles’ of the surrounding air by rapidly vertebrates as had been thought. rate of work during flight. flexing their muscles. It is now Most flying insects have higher AFTER In insects… the active metabolic rates than other animals 1991 German biologist Harald flight muscles… are, but their small body size means they Esch describes how muscle metabolically, the most lose heat rapidly, so they cannot keep “warm-up” plays a role in brood active tissues known. their temperature constant at all incubation and colony defense times. The minimum temperature as well as flight preparation. Bernd Heinrich that allows an insect to fly varies from species to species, but the 2012 Using infrared maximum temperature falls within thermography, Spanish 104–113°F (40–45°C). To prevent zoologist Jose R. Verdu shows overheating, insects can transfer how some dung beetle species heat from the thorax to the abdomen. heat or cool their thorax to improve flight performance. Many larger flying insects would remain grounded if they were not able to increase the temperature of their flight muscles. These insects

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS THE VARIETY OF LIFE 127 See also: Evolution by natural selection 24–31 ■ Ecophysiology 72–73 Heat regulation ■ Animal ecology 106–113 ■ Organisms and their environment 166 Honeybees are renowned for “quiver” the muscles that control A tortoiseshell butterfly feeds on controlling the temperature the upbeat and downbeat of the a dandelion. Most butterflies can angle of their hive. When it gets too wings to generate heat before their wings upward in an attempt hot, they ventilate it by using taking off. Once flying, the muscles to cool down, in a process called their wings to fan the hot air use large amounts of chemical behavioral thermoregulation. out of the nest. When it gets energy but only some of it is used too cold, the bees generate to beat the wings; the rest becomes Other insects use even more metabolic heat by rapidly more heat. This, combined with the remarkable methods to regulate their contracting and relaxing their warmth of direct sunlight, means body temperature. When a mosquito flight muscles. They also use a flying insect risks overheating. drinks the warm blood of a mammal, heat as a defense mechanism. this raises its body temperature. To Japanese giant hornets are To solve this problem, many compensate, it produces droplets of fierce predators of honeybees. species have a heat-exchange fluid that are kept at the end of the Capable of killing large mechanism that shifts excess heat abdomen; evaporative cooling of numbers quickly, they pose a from the thorax to the abdomen, these droplets lowers the insect’s serious threat to bees’ nests. allowing the insect to maintain temperature. Dung beetles construct Hornets begin their attacks by a steady temperature in its thorax. balls of dung in which females lay picking off single honeybees their eggs. Some dung beetles are at the entrance to the hive. Range of techniques able to raise the temperature of their However, Japanese honeybees By changing the angle of their thorax so they can roll heavier balls. defend themselves with wings, butterflies control their body self-generated heat. If a hornet temperature. When they are trying The range of thermoregulation attacks, they swarm around it, to warm up, holding their wings techniques shows how life forms vibrating their wings to raise wide open maximizes the amount evolve to better fit their environment. their collective temperature. of sunshine falling on them. When They can also inspire technology: Since the hornet cannot they are trying to cool down, they arrays of solar panels angled to tolerate a temperature above move into shade or angle their track the Sun capture maximum 114.8°F (46°C) whereas the wings upward so that less direct amounts of solar radiation—just like bees can survive at almost sunlight shines on their surface. butterfly wings. ■ 118.4°F (48°C), the attacker eventually dies. This Japanese giant hornet is raiding nursery cells in a bees’ nest in Hase Valley, Japan. Hornets seek to devour the bee larvae inside the cells.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYST

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS EMS

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 130 INTRODUCTION Richard Bradley Charles Elton The journal Ecology Nelson Hairston, describes how plants, develops the idea of posthumously publishes Frederick Smith, and the food web in Animal Raymond Lindeman’s article Lawrence Slobodkin’s pollinating insects, Ecology and introduces “The trophic-dynamic “green world hypothesis” and insectivores rely the concept of the argues that the predator– on one another in a ecological niche. aspect of ecology.” prey balance is key to flourishing ecosystems. food chain. 1718 1927 1942 1960 1859 1935 1957 Charles Darwin Arthur G. Tansley coins the G. Evelyn Hutchinson describes food term ecosystem, arguing establishes the concept webs in his On the that an environment and all Origin of Species. its living organisms have of niche breadth at the Cold Spring to be seen as a single, interactive whole. Harbor Symposia on Quantitative Biology. W hen Aristotle wrote The concept of the ecosystem (“a They identified both the top-down about plant and animal recognizable self-contained entity”) pressures exerted by predators and species existing for the followed soon after, when in 1935, the bottom-up pressures exerted by sake of others, he showed a basic British botanist Arthur Tansley limitations on food supply. Twenty understanding of food chains— wrote that organisms and their years later, American ecologist as have countless observers of the environment should be considered Robert Paine wrote of the trophic natural world since ancient Greek one physical system. In his Ph.D. cascade effect—the way a system times. Arab scholar Al-Jahiz thesis, American ecologist is changed by the removal of a key described a three-level food chain Raymond Lindeman expanded species. He described changes to in the 9th century, as did the on Tansley’s work, positing that the food web after the experimental Dutch microscopist Antonie van ecosystems are composed of removal of the ocher starfish from Leeuwenhoek in 1717. British physical, chemical, and biological an intertidal zone. This predatory naturalist Richard Bradley processes “active within a space– echinoderm was shown to be a published more detailed findings time unit of any magnitude.” keystone species, playing a crucial on food chains in 1718, and in 1859, role within its ecosystem. Charles Darwin described a “web Lindeman also conceived the of complex relations” in the natural idea of feeding levels, or trophic Island isolation environment in his book On the levels, each of which is dependent Habitat fragmentation is now a Origin of Species. The concept of a on the preceding one for its survival. major problem in most terrestrial food web, with many predator-prey In 1960, the American team of environments because it leaves interactions, was then further Nelson Hairston, Frederick Smith, specialist organisms isolated. developed by Charles Elton in his and Lawrence Slobodkin published For that reason, research into the classic Animal Ecology (1927). findings on the factors controlling biogeography of islands—those animals on different trophic levels.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 131 John Maynard Smith Hal Caswell proposes Scientists at the defines his a “neutral” theory Biodiversity and Ecosystem Function Evolutionarily Stable of biodiversity, suggesting conference in Paris Strategy (ESS) theory that competitors are often examine how the equal, and chance plays in On Evolution. loss of species the deciding role in impacts ecosystems. what does or doesn’t thrive. 1972 1976 2000 1967 1973 1980 2015 Robert MacArthur Crawford Stanley Robert Paine coins the term A study of grassland plants examines the Holling uses the “trophic cascade” after his suggests that biodiversity term ecological field experiments show the increases an ecosystem’s biodiversity of resilience to show how isolated communities ecological systems effect on an ecosystem resistance during survive change. when a keystone species and resilience after in The Theory of Island Biogeography. is removed. climate events. surrounded by ocean but also evolutionarily stable strategy (ESS) after a trauma. Ecologists now “islands” of distinct habitat to describe the best behavioral understand that ecosystems can surrounded by a very different strategy for an animal competing have more than one stable state, environment—is so important with others living in its vicinity. and that resilient systems are not in ecology. In the US in the 1960s, This strategy depends on how the always good for biodiversity. Edward O. Wilson and Robert other animals behave and is MacArthur discovered key factors determined by the animal’s genetic When the populations of many determining species diversity, success—if it makes the wrong species are declining or becoming immigration, and extinction on decisions, it will not live long and locally extinct, ecologists are once islands. James Brown later did cannot pass on its genes. The more focusing their attention on similar work on animal populations overall balance between the ecosystem resilience. Many, in isolated patches of forest ridge in evolutionarily stable strategies of including French ecologist Michel California. Such work has showed all the animals in an ecosystem is Loreau, believe that if diversity in how to identify species most at risk called the evolutionarily stable state. an ecosystem is reduced, the whole of extinction due to isolation. system will be less likely to resist Canadian ecologist Crawford major impacts such as the effects of Stability and resilience Stanley Holling introduced the idea climate change. Today, Loreau and One major contribution to the of resilience—how ecosystems others are working toward finding a understanding of ecosystem persist in the wake of disruptive new general theory that can dynamics was the concept of the changes such as fire, flood, or explain the relationship between evolutionarily stable state. In the deforestation. A system’s resilience ecosystem biodiversity and 1970s, British biologist John can be seen in its capacity to absorb resilience in order to understand Maynard Smith used the term disturbance, or the time it takes to and combat the effects of today’s return to a state of equilibrium environmental challenges. ■

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 132 IESOSVUFENPNRPEAYCOTERDUSTIRSSEOTA’FISRNTYWCHFTOEOPRRRAKERTSSTHTE THE FOOD CHAIN IN CONTEXT The food chain A ll animals must eat other living things in order to KEY FIGURE Apex predator receive the nutrients they Richard Bradley (1688–1732) Larger predator need to grow and function. A food (tertiary consumer) chain shows the feeding hierarchy BEFORE of different animals in a habitat. 9th century Arab scholar Carnivore For example, the chain would show Al-Jahiz describes a three- (secondary consumer) that foxes eat rabbits but rabbits level food chain of plant matter, never eat foxes. Although there rats, snakes, and birds. Herbivore were earlier notions of a hierarchy (primary consumer) of animals linked to each other in 1717 Dutch scientist Antonie a food chain, British naturalist van Leeuwenhoek observes Producer (autotroph) Richard Bradley brought more how haddock eat shrimp and detail to this idea in his book New cod eat haddock. Improvements in Planting and Gardening (1718). He noted that AFTER each plant had its own particular 1749 Swedish taxonomist Carl set of insects that lived off it and Linnaeus introduces the idea proposed that the insects in turn of competition. received the attentions of other organisms of “lesser rank” that fed 1768 John Bruckner, a Dutch on them. In this way, he believed naturalist, introduces the idea that all animals relied upon each of food webs. other in a self-perpetuating chain. 1859 Charles Darwin writes Producers and consumers about food webs in On the The modern concept of a food chain Origin of Species. explains that some organisms produce their own food. These are 1927 British zoologist Charles known as producers, or autotrophs. Elton’s Animal Ecology outlines Plants and most algae fall into this principles of animal behavior, category, normally using the energy including food chains. of sunlight to convert water and carbon dioxide into glucose, at the

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 133 See also: Predator–prey equations 44–49 ■ Mutualisms 56–59 ■ Keystone species 60–65 ■ Optimal foraging theory 66–67 ■ Animal ecology 106–113 ■ The ecosystem 134–137 ■ Trophic cascades 140–143 ■ Ecological resilience 150–151 Each species has a specific place in nature, in geographic location and in the food chain. Carl Linnaeus same time as releasing oxygen. of the food chain, but there is always An apex predator, such as the bronze This process, photosynthesis, is the a producer at the bottom, and all whaler shark, has no natural predators. first step towards creating food. In levels above it are consumers. In the temperate waters of the ocean places where there is no sunlight, Animals that only eat plants are off South Africa the shark can find vast organisms producing their own herbivores, or primary consumers, quantities of sardines to eat. food are called chemotrophs. Those and they include cattle, rabbits, in the deep ocean, for example, get butterflies, and elephants. Those of prey. The animals at the top of the energy they need from chemicals that eat only other animals are their food chain are apex predators. released by hydrothermal vents. carnivores, or secondary consumers; They include consumers such as these include thrushes, dragonflies, tigers, killer whales, and golden Animals that eat producers and and hedgehogs. In turn, secondary eagles that are not preyed upon creatures that eat other animals are consumers may be eaten by larger by other animals. called consumers, or heterotrophs. predators, or tertiary consumers, There may be two, three, or more such as foxes, small cats, and birds The food chain does not break levels of these in any particular part when plants and animals die. infections were caused by tiny Detritus feeders (detritivores) prey Richard Bradley organisms, visible only with a on the remains, recycling nutrients microscope. His investigations and energy for the next generation Born around 1688, noted British into the productivity of rabbit of producers to use. botanist Richard Bradley gained warrens and fish lakes led to patrons after writing a Treatise his theories about predator–prey Food webs of Succulent Plants at the age of relations. Bradley died in 1732. Observers after Bradley suggested 22. With no university education, that animals were not simply part he was nonetheless elected a Key works of a food chain, but a larger and Fellow of the Royal Society and more complex “food web” that later became the first professor 1716–27 The History of comprises all the food chains in a of botany at Cambridge. Succulent Plants location. This idea was put forward 1718 New Improvements in by Dutch naturalist John Bruckner Bradley’s research interests Planting and Gardening in 1768, and later taken up by were wide-ranging, including 1721 A Philosophical Account of Charles Darwin, who called the fungal spore germination and the Works of Nature variety of connected feeding plant pollination. In some cases, relationships between species Bradley was ahead of his time; a “web of complex relations”. ■ he argued, for example, that

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 134 FOSAAOLRROOLGEUDRAOPNCROFIEGOTSSERAMNNOOSTIFSTIAHMLESR IN CONTEXT THE ECOSYSTEM KEY FIGURE Arthur Tansley (1871–1955) BEFORE 1864 George Perkins Marsh, an American conservationist, publishes Man and Nature, which hints at the concept of ecosystems. 1875 Austrian geologist Eduard Suess proposes the term “biosphere.” AFTER 1953 American ecologists Howard and Eugene Odum develop a “systems approach” to studying the flow of energy through ecosystems. 1956 American ecologist Paul Sears highlights the role of ecosystems in recycling nutrients. 1970 Paul Ehrlich and Rosa Weigert warn of potentially destructive human interference in ecosystems. B ritish biologist Arthur Tansley was the first to insist that communities of organisms in a particular area had to be seen in a wider context, including the nonliving elements of that area. Tansley argued that in a given region, all the living organisms and their geophysical environment together form a single, interactive entity. Borrowing a concept from engineering, he saw the network of interactions as a dynamic, physical system. On the suggestion of his colleague Arthur Clapham, he coined the word “ecosystem” to describe it.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 135 See also: Animal ecology 106–113 ■ The food chain 132–133 ■ Energy flow through ecosystems 138–139 ■ The biosphere 204–205 ■ The Gaia hypothesis 214–217 ■ Environmental feedback loops 224–225 ■ Ecosystem services 328–329 Tropical coral reefs are some of the most diverse ecosystems of all, full of fish, sea turtles, crustaceans, mollusks, and sponges, as well as corals. This idea had been developing long before Arthur Tansley published his influential paper on the subject in 1935. As early as 1864, conservationist George Perkins Marsh, in his book Man and Nature, had identified “the woods,” “the waters,” and “the sands” as different types of habitat. He examined how the relationship between them and the animals and plants that lived in them could be upset by human activity. Interconnected systems a single unit, and using the term nitrogen, and soil minerals, which By the 20th century, the idea had “biome” to describe the whole are essential to the functioning of taken hold that these and other complex of organisms inhabiting the systems as a whole. The biotic environments could be understood a given region. components within an ecosystem as discrete entities, with distinctive not only interact with one another, interactions between the living Tansley envisaged ecosystems but also with the abiotic parts. and inert elements within them. In as being made up of biotic (living) Thus, within any given ecosystem, 1916, American ecologist Frederic elements and abiotic (nonliving) the organisms adapt to both the ❯❯ Clements built on this idea in his elements such as energy, water, work on plant succession, referring to a “community” of vegetation as Arthur G. Tansley A free-thinking Fabian socialist He retired in 1937, but and atheist, Arthur Tansley was maintained a special interest one of the most influential in conservation. Tansley was ecologists of the 20th century. appointed the first Chairman of Born in London in 1871, he studied the UK’s Nature Conservancy in biology at University College 1950, five years before his death. London, where he later taught. In 1902, he founded the journal Key works New Phytologist and he later established the British Ecological 1922 Types of British Vegetation Society, becoming founding editor 1922 Elements of Plant Ecology of its Journal of Ecology. In 1923, 1923 Practical Plant Ecology he took a break from teaching to 1935 “The use and abuse of study psychology with Sigmund vegetational terms and Freud in Vienna. He was later concepts,” Ecology Sherardian Professor of Botany 1939 The British Islands and at the University of Oxford. Their Vegetation

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 136 THE ECOSYSTEM biological and physical elements matter: plants absorb carbon A small glacial lake, or tarn, in the of the environment. The different dioxide (CO2) from the atmosphere English Lake District. Each tarn has types of ecosystem can be defined and nutrients from the soil to grow. an ecosystem that varies according by their physical environments. These plants release life-sustaining to many factors, including the degree There are four categories of oxygen into the atmosphere by of nutrient enrichment in the water. ecosystem: terrestrial, freshwater, respiration, and provide food for marine, and atmospheric. These animals. Animal excreta and dead Each ecosystem is located in a can be further subdivided into matter also release carbon, and particular area, with characteristics various types according to different provide material to be decomposed unique to its environment, and physical environments and the by bacteria and fungi, in turn behaves as a self-contained and biodiversity within them. Terrestrial providing soil nutrients for plants. self-regulating system. Together, ecosystems, for example, can be the patchwork of ecosystems subdivided into deserts, forests, Arthur Tansley also argued across the globe form what grasslands, taigas, and tundras. that these internal processes Austrian scientist Eduard Suess within an ecosystem conform to called the biosphere—the sum Dynamic feedback what he described as “the great total of all ecosystems. Tansley’s most important insight universal law of equilibrium.” was that these discrete communities Self-regulating, these processes External factors of living and nonliving components have a natural tendency toward Various external factors, such as form dynamic systems. In a stability. The cycles within an climate and the geological makeup terrestrial ecosystem, for example, ecosystem contain feedback loops of the surrounding environment, the organisms interact to recycle that correct any fluctuations from can affect an ecosystem. One a state of equilibrium. constant external force that affects all ecosystems is the Sun. The The dynamic transfer of energy supply of energy that it provides enables photosynthesis and the In this ecosystem, plants use the Sun’s energy capture of CO2 from the atmosphere; for photosynthesis. As shown by the pale arrows, some of this energy is distributed this energy is passed on—to herbivores, who eat through the ecosystem and through plants; to predators, who eat herbivores; and to the food chain. In the process, some saphrophytes, who take energy from decomposing of this energy dissipates as heat. remains and transfer nutrients to the soil. At each stage, some energy is lost as heat. Other external factors, however, can arise unexpectedly to create Heat pressures on ecosystems. All ecosystems are subjected to Heat external disturbances from time to time, and must then go through Plants Heat a process of recovery. These (producers) disturbances include storms, Frog (predator) Saphrophytes Fish Nutrients and parasites (herbivores) (decomposers)

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 137 There is no waste in more fragile, and if they are wholesale destruction of habitat functioning … ecosystems. disturbed may never be able and the consequent depletion of its All organisms, dead or alive, to regain their equilibrium. biodiversity. In addition, some have are potential sources of food suggested that human influence The resistance and resilience has created a new category for other organisms. of an ecosystem is generally of ecological systems, dubbed G. Tyler Miller thought to be related to its “techno-ecosystems.” For example, biodiversity. If, for example, “cooling ponds” are manmade Science writer there is only one species of plant ponds, built to cool down nuclear performing a particular function power plants, but they have become earthquakes, floods, droughts, and in the system, and that species is ecosystems for aquatic organisms. other natural phenomena, but are not frost-resistant, an abnormally increasingly the result of human severe winter could deplete the The relationship between activity—through the destruction species enough to have a major humans and natural ecosystems of natural habitats by deforestation, impact on the system as a whole. is not all negative. In recent years, urbanization, pollution, and the In contrast, if there are several scientific data has fueled public cumulative effects of anthropogenic species with that role in the awareness of the benefits that (human-induced) climate change. system, it is more likely that one ecosystems afford humankind, Humans can also be responsible will be resistant to the disturbance. including the provision of food, for the introduction of invasive water, nutrients, and clean air, species. Without these external The human factor as well as the management of factors, an ecosystem would Some disturbances can be severe disease and even climate. There maintain its state of equilibrium, enough to be catastrophic for an is now a growing commitment from and retain a stable identity. ecosystem, damaging it beyond many governments across the the point of recovery and so world to use these benefits both causing a permanent change responsibly and sustainably. ■ in its identity, or even its demise. The fear is that much of the The Eden Project, in Cornwall, UK, disturbance caused by human simulates a rain forest ecosystem in activity has the potential to one of its giant dome greenhouses. The cause such permanent damage, domes’ panels are slanted to absorb particularly when it involves the plenty of light and thermal energy. Resistance and resilience Ecosystems are often strong enough to withstand some natural external disturbances and retain their equilibrium. Some are more resistant to disturbance than others, and have adapted to the particular disturbances normally associated with their environment. In some forest ecosystems, for example, the periodic fires caused by electrical storms cause only a minor imbalance in the ecosystem. Even when severely disrupted by external disturbances, some ecosystems have a resilience that enables them to recover. However, other ecosystems are

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 138 OBLIYFFAPERVISOACSSETUSPNSPEEOTSRWTOERDK ENERGY FLOW THROUGH ECOSYSTEMS IN CONTEXT I n 1941, Raymond Lindeman his Ph.D., but his paper was initially submitted the final chapter of rejected by Ecology, for being KEY FIGURE his Ph.D. thesis for publication too theoretical. Raymond Lindeman in the prestigious journal Ecology. (1915–42) Titled “The Trophic-dynamic Lindeman had painstakingly Aspect of Ecology,” it was about sampled everything in the lake, BEFORE the relationship between food from the aquatic plants and 1913 American zoologist chains and the changes over time microscopic algal plankton to the Victor Shelford produces the in a community of species. worms, insects, crustaceans, and first illustrated food webs. fish that fed upon one another and Lindeman had spent five years depended on each other for their 1920 Frederic Clements studying the life forms in an aging existence. He stressed that the describes how groups of plant lake at Cedar Creek Bog, Minnesota, community of organisms could not species are associated in and was especially interested in be properly understood on its own; communities. the changes in the lake as, year instead, it must be examined in the by year, aquatic habitat gradually context of its wider surroundings. 1926 Russian geochemist gave way to land. He received The living (biotic) organisms and Vladimir Vernadsky sees that chemicals are recycled between Producers (plants and Primary consumers living and nonliving things. algae) depend on energy are dependent on an gathered from the Sun and abundance of plants 1935 Arthur Tansley develops nutrients from decomposed the concept of the ecosystem. and algae to eat. organic matter. AFTER 1957 American ecologist Life is supported Secondary consumers Eugene Odum uses radioactive by a vast network rely on an abundance of elements to map food chains. primary consumers as of processes. 1962 Rachel Carson draws their food source. attention to the accumulation of pesticides in food chains, in her book Silent Spring.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 139 See also: Ecological niches 50–51 ■ Nonconsumptive effects of predators Measuring on their prey 76–77 ■ The food chain 132–133 ■ The ecosystem 134–137 productivity Boneworms are deep-sea creatures Lindeman’s trophic-dynamic that feed on the remains of animals theory helped to clarify the such as whales. They grow “roots” to idea of ecosystem productivity, break down the bones, thereby recycling which ecologists had previously nutrients from the dead material. defined in rather vague terms. The productivity of a plant the nonliving (abiotic) components Lindeman also demonstrated how or animal is measured by its (air, water, soil minerals) were some of the energy at each trophic growth in organic material, linked together by nutrient cycles level is lost as waste, or converted or biomass. This is never equal and energy flows. This entire into heat when organisms respire. to the organism’s energy system—the ecosystem—was By combining the results of his own input, because the conversion the central ecological unit. study with data from a wide range of solar energy into leaf in the of other sources, he was able to case of plants, or the conversion Producers and consumers build a picture of this system as it of food into flesh in the case of Lindeman’s research showed how worked in Cedar Creek Bog. an animal, is never 100 percent an ecosystem is powered by a efficient. Some energy is stream of energy from one organism British ecologist G. Evelyn released as heat, most of which to another. The organisms can be Hutchinson, considered to be one is lost via respiration—an grouped into discrete “trophic levels” of the founding fathers of modern essential aspect of metabolism (feeding levels)—from producers ecology, was Lindeman’s mentor at in all living things. (plants and algae), which absorb Yale University. He recognized the energy in the form of sunlight to importance of his student’s work to Warm-blooded animals lose make food, to consumers (animals). the future development of ecology, a lot of heat when their body “Primary consumers” are the and he lobbied for Lindeman’s temperature is much higher herbivores that eat the plants; paper to be accepted. Lindeman, than that of their surroundings. “secondary consumers” are animals who had always suffered from ill All animals also lose energy that eat the herbivores. Each trophic health, died in 1942 from cirrhosis when they excrete urine. In level depends on the preceding one of the liver at the tragically young addition, not all the material for its survival. At the same time, age of 27, just four months before in an animal’s food can be dead material accumulating from his trophic-dynamic paper—now digested in its gut, and the each stage is broken down by seen as a classic in its field—was material that is expelled as decomposers, such as bacteria and finally published. ■ feces represents unused fungi, and materials in the form of chemical energy. nutrients are recycled back to feed … biological communities plants and algae. could be expressed as This thermal image of an elephant shows how some of the networks or channels through animal’s heat is lost. Both its body which energy is flowing and temperature and its manure are warmer than the surroundings. being dissipated… G. Evelyn Hutchinson

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 140 ITSHGERWEOENRLD IN CONTEXT TROPHIC CASCADES KEY FIGURE Nelson Hairston (1917–2008) BEFORE 1949 Aldo Leopold publishes A Sand County Almanac, drawing attention to the ecological impact of hunting wolves on mountain plant life. AFTER 1961 Lawrence Slobodkin, an American marine ecologist, publishes The Growth and Regulation of Animal Populations, a key ecology textbook. 1980 Robert Paine describes the “trophic cascade effect,” when predators are removed from an intertidal ecosystem. 1995 The reintroduction of gray wolves to Yellowstone National Park sets in motion a series of ecosystem changes. S oon after the end of World War II, Aldo Leopold, an ecologist and one of the top wildlife management experts in the United States, challenged the view that wolves should be eradicated because they threatened livestock. In A Sand County Almanac, he wrote of the destructive effect that removing this top predator would have on the rest of the ecosystem. In particular, he said, it would lead to overgrazing of mountainsides by deer. Leopold’s view was an early expression of the idea of trophic cascades, although he himself did not use that term. Predators help keep a balance in a food web by regulating the populations of other animals. When

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 141 See also: Predator–prey equations 44–49 ■ The food chain 132–133 ■ The ecosystem 134–137 ■ Energy flow through ecosystems 138–139 ■ Evolutionarily stable state 154–155 ■ Biodiversity and ecosystem function 156–157 Ocher starfish prey on sea creatures different trophic levels. They he described changes in food such as mussels and limpets. In a concluded that populations of webs that were brought about famous experiment, Robert Paine took producers, carnivores, and by the experimental removal them out of their rock pools to observe decomposers are limited by their of predatory starfish from the the effect on the rest of the food web. respective resources. Competition intertidal zone in Washington occurs between species on each of State. The concept of trophic they attack and eat prey, they affect these three trophic levels. They also cascades is now generally accepted, the number and behavior of that found that herbivore populations although debate continues as to prey—since prey move away when are seldom limited by the supply of how widespread they are. predators are present. The impact plants, but are limited by predators, of a predator can extend down to the so they are unlikely to compete Top-down cascades next feeding level (trophic level), with other herbivores for common This type of cascade is clearly affecting the population of the prey’s resources. The paper highlighted demonstrated when a food chain own food source. In essence, by the important role of top-down is interrupted by the removal of controlling the population density forces (predation) in ecosystems, a top predator. The ecosystem and behavior of their prey, predators and bottom-up forces (food supply). may continue to function despite indirectly benefit and increase the the shift in species composition; abundance of their prey’s prey. American ecologist Robert alternatively, the removal of one Paine was the first to use the term species may lead to the ❯❯ Indirect interaction that occurs “trophic cascade” when, in 1980, across feeding levels is described by ecologists as a trophic cascade. Predators eat By definition, trophic cascades must herbivore prey cross at least three feeding levels. Four- and five-level trophic cascades Bottom-up cascade Top-down cascade are also known, although these are less common. Predators move into the If predators are area and numbers increase removed … Herbivore population Prey population increases increases Controlling factors Increased rainfall Overgrazing brings In 1960, the American ecologist encourages vegetation habitat change and loss Nelson Hairston and his colleagues Frederick Smith and Lawrence of species richness Slobodkin published a key paper entitled “Community Structure, Herbivore prey eat plants Population Control, and Competition,” which examined the factors that control populations of animals on

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 142 TROPHIC CASCADES ecosystem’s breakdown. In the US, benthic invertebrate species. This Just as a deer herd lives a trophic cascade on the coast of in turn led to an increase in floating in mortal fear of its wolves, southern New England is believed nutrients, which ultimately boosted to be responsible for the die-off of phytoplankton rather than species so does a mountain live saltmarsh habitat. Recreational on the sea floor. The net effect of in mortal fear of its deer. anglers have reduced the number the crabs’ arrival was to transfer of predatory fish to such an extent nutrients from the sea floor to the Aldo Leopold that the number of herbivorous water column—the water between crabs has expanded dramatically. the sediment and the surface—and plants support more herbivores and The resulting increase in the to degrade the ecosystem. more predators. This is in contrast to consumption of marsh vegetation top-down cascades, in which more has had a knock-on effect on other Bottom-up cascades predators lead to fewer herbivorous species that depend on it. If a plant—a primary producer— prey and a greater mix of plants. is removed from an ecosystem, a Trophic cascades can also be bottom-up cascade may result. For Beetles, ants, and moths disturbed by the introduction and example, if a fungal disease causes Investigating trophic cascades spread of a nonnative species, as grass to die-off, a rabbit population in four-tier systems is more difficult, happened when the omnivorous that depends on it will crash. In because predators at the top mud crab indigenous to waters turn, the predators that eat rabbits feeding level may eat predators at on the east coast of North America will starve or be forced to move the level below and also herbivores and Mexico became common in away, and the entire ecosystem below them, so the relationships the Baltic Sea in the 1990s. Crabs, could break down. Conversely, become very complex. In 1999, which are keystone species in if planting or conservation efforts researchers studying trophic many coastal food webs, feed on boost the mix of plant life, more cascades in tropical rain forest in benthic (seafloor) communities— herbivores (including the pollinators Costa Rica got around this problem bivalves, gastropods, and other that help plants reproduce and by studying a system of three small invertebrates—with spread) will be attracted, and with trophic levels of invertebrates, in devastating efficiency, creating them more predators. which the top predator—a clerid a strong top-down cascade. The beetle—ate the predatory ants increase in the number of mud In the bottom-up model, the in the level below it, but not the crabs in the Baltic, where there are responses of herbivores and their herbivores in the level below that. no equivalent predators, resulted predators to increased plant variety When the number of predatory in a dramatic decline in the mix of follow in the same direction: more beetles in the study area was increased, the population of predatory ants fell dramatically. This reduced the pressure on dozens of species of herbivorous Californian yellow bush lupines are fast growing and invasive. The plant can upset the ecosystem by causing elevated nitrogen levels that attract nonnative species.

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 143 Early humans and megafauna Steller’s sea cow was a giant cascade, triggered by the hunting In the last 60,000 years, which sirenian discovered by the naturalist to virtual extinction of sea otters for includes the end of the last ice Georg Steller in 1741. Its extinction is the fur trade. The over-exploitation of age, about 51 genera of large the cause of debate: was it hunted to sea otters allowed the population mammals became extinct in death, or did its food source disappear? of sea urchins, their usual prey, to North America. Most were rise above a critical threshold. Sea herbivores, including ground invertebrates, which therefore ate urchins eat kelp, so the growth of sloths, mastodons, and large more vegetation. The leaf area their population led to a collapse in armadillos, but many were of the plants in the study was the extent of kelp forests—the sea carnivores, such as American consequently reduced by half. cows’ food source. Although the lions and cheetahs, scimitar sea cows themselves were not cats, and short-faced bears. Not all the “players” in trophic being hunted, they soon became cascades are obvious or visible. extinct. Understanding how such Many of the extinctions Some are tiny and live underground. interventions, and the introduction of occurred between 11,500 and For example, yellow bush lupines— nonindigenous species, can damage 10,000 years ago, shortly after plants that live on the Californian trophic cascades is vital in shaping the arrival and spread of the coast—are consumed by the conservation measures today. ■ Clovis people, who were caterpillars of ghost moths, which hunters. One of the most eat the lupines’ roots. In turn, Herbivores are convincing theories about nematodes—wormlike usually expected to be these developments is the invertebrates—parasitize the well fed and carnivores “second-order predation caterpillars. If these nematodes are usually expected hypothesis,” which suggests are in the soil, they will limit the that the humans triggered a population of caterpillars, and fewer to be hungry. trophic cascade. The people of the lupines’ roots will be affected. Lawrence Slobodkin killed the large carnivores, which competed with them Extinction events for prey. As a result, predator In extreme cases, a trophic cascade numbers were reduced can lead to species extinction—as and prey populations rose in the case of Steller’s sea cows, disproportionately, resulting marine mammals that once lived in in overgrazing. The vegetation the Bering Strait but were declared could no longer support the extinct in 1768. It has recently been herbivores, with the result argued that this extinction was that many herbivores starved. caused by a calamitous trophic Cave paintings in Altamira, Spain, show the importance of bison to early humans. The wild population became extinct in 1927, but captive herds have since been reintroduced.

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РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 146 ISLAND BIOGEOGRAPHY IN CONTEXT KEY FIGURES Robert H. MacArthur (1930–72), Edward O. Wilson (1929–) BEFORE 1948 Canadian lepidopterist Eugene Munroe suggests a correlation between island size and butterfly diversity in the Caribbean. AFTER 1971–78 In the US, biologist James H. Brown studies mammal and bird species variety on forest “islands” in the Great Basin of California and Utah. 2006 Canadian biologists Attila Kalmar and David Currie study bird populations on 346 oceanic islands and discover that species variety depends on climate as well as area and isolation. Unless we preserve I sland, or insular, biogeography Mangrove-fringed islands in the the rest of life, as a examines the factors that Florida Keys—now protected for their sacred duty, we will be affect the species richness of diverse range of marine and terrestrial endangering ourselves isolated natural communities. life—were the focus of research to test by destroying the home Charles Darwin, Alfred Russel the island biogeography theory. in which we evolved. Wallace, and other naturalists had Edward O. Wilson written about island flora and fauna pools within a dry landscape, or in the 19th century. Their studies fragments of mountain forest were conducted on actual islands between nonforested valleys. in the ocean, but the same methods can be used to look at any patch In the mid-20th century, of suitable habitat surrounded by ecologists began more intensive unfavorable environment that studies into species distribution limits the dispersal of individuals. on different islands, and how and Examples include oases in the why they varied. In the US, desert, cave systems, city parks in biologists Edward Wilson and an urban environment, freshwater Robert MacArthur constructed the first mathematical model of the

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS ECOSYSTEMS 147 See also: Evolution by natural selection 24–31 ■ Predator-prey equations 44–49 ■ Field experiments 54–55 ■ The ecosystem 134–137 Random dispersal of organisms to islands Mainland Island 1 Island 3 Island 2 Robert H. MacArthur An island’s size and distance from the mainland both affect its species richness. Islands closer to the mainland Born in Toronto, Canada, in will receive more random dispersion of organisms; the larger 1930, and later relocating to island gets the most, the island furthest away gets the least. Vermont in the US, Robert MacArthur originally studied factors at play in island ecosystems because if native species are mathematics. In 1957, he and, in 1967, they outlined a new pushed out of prime habitat by new received his Ph.D. from Yale theory of island biogeography. immigrants, they have a better University for his thesis chance of finding an alternative, exploring ecological niches Their theory proposed that each albeit imperfect (“suboptimal”) occupied by warbler species island reflected a balance between habitat. Larger islands are also in conifer forests. MacArthur’s the rate of new species arriving likely to have a greater variety of emphasis on the importance there and the rate at which existing habitats or microhabitats in which of testing hypotheses helped species become extinct. For example, to accommodate new immigrants. transform ecology from an a habitable but relatively empty A combination of variety and lower exclusively observational island would have a low extinction rates of extinction produces a field to one that employed rate since there are fewer species greater species mix than on a small experimental models as well. to become extinct. When more island—the “species-area effect.” This methodology is reflected species arrive, competition for The actual species in the mix will in The Theory of Island limited resources increases. At a change over time, as a result of Biogeography, which he certain point, smaller populations colonization and extinction, but will coauthored with Edward O. will be outcompeted, and the rate remain relatively diverse. Wilson. MacArthur received of species extinction will rise. An awards throughout his career, equilibrium point occurs when the Monitoring mangroves and was elected to the species immigration rate and the In 1969, Wilson and his student National Academy of Sciences rate of those becoming extinct are Daniel Simberloff conducted a field in 1969. In 1972, he died of equal; this may remain constant experiment that tested the theory renal cancer. The Ecological until a change occurs in either rate. on six small mangrove islands in Society of America awards a the Florida Keys in the US. They biennial prize in his name. The theory also proposes that recorded the species living there, the rate of immigration depends then fumigated the mangroves to Key works on the distance from the mainland, remove all the arthropods, such as or another island, and declines with insects, spiders, and crustaceans. 1967 The Theory of Island increased distance. The area of an In each of the next two years, ❯❯ Biogeography island is a further factor. The larger 1971 Geographical Ecology: it is, the lower its rate of extinction, Patterns in the Distribution of Species

РЕЛИЗ ПОДГОТОВИЛА ГРУППА \"What's News\" VK.COM/WSNWS 148 ISLAND BIOGEOGRAPHY Islands are The water acts as island of Cuba, because economic surrounded by water. a physical barrier, sanctions since the 1960s have preventing many species meant that fewer boats (and their Islands are from entering or leaving. lizard stowaways) dock in Cuba. ecological systems. As species arrive “Island” habitats they counted returning species and depart, island In the early 1970s, American to observe their recolonization. populations evolve. biologist James H. Brown applied The Florida Keys experiment the Wilson–MacArthur model to showed that distance did indeed floating vegetation). Most of these “islands” of coniferous forest on 19 play an important role: the farther factors apply to any similar, isolated mountain ridges in the Great Basin an island was from the mainland, habitats, not just actual islands. of California and Utah. The ridges the fewer invertebrates returned to are separated from each other by recolonize the area. The impact of humans—who a vast sagebrush desert. Brown probably began visiting isolated discovered that the diversity and New waves of immigration can, islands in the Pacific at least 3,000 distribution of small mammals however, save even faraway island years ago—has sometimes been (excluding bats) in the isolated species from extinction. This is dramatic. In recent centuries, forests could not be explained in more likely to happen with certain people took dogs, cats, goats, terms of an equilibrium between bird species—which can travel long and pigs with them when they colonization and extinction. Some distances quickly—than with, for colonized islands in the Pacific species had become extinct, but example, small mammals. There is and elsewhere; inadvertently, they no new species had arrived for also the so-called target effect, also carried rats on their boats. millions of years, so Brown dubbed where some islands are more On many islands, rats ate the eggs the mammals “relicts.” A few years favored destinations because of the of breeding seabirds and the later, his analysis of resident bird habitat they provide. Given the seeds of endemic plants, some of populations on the ridges revealed choice of a treeless island and one which grew nowhere else. On the that new bird species had arrived with woodland, a tree-nesting bird Galapagos Islands, dogs ate from larger, similar forests in the will naturally opt for trees. tortoise eggs, native iguanas, and Rocky Mountains to the east and even penguins. Goats competed in the Sierra Nevada to the west. Human impact with Galapagos tortoises for food Brown concluded that certain The key factors influencing the and wiped out up to five species of species groups—especially those species mix on an oceanic island plant on the Santiago Islands. that fly—are more likely to be are its degree of isolation, how long successful immigrants than others. it has been isolated, its size, the The arrival of humans, however, suitability of its habitat, its location has not always reduced species Destroying rainforest relative to ocean currents, and richness on islands. Researchers for economic gain chance arrivals (for example, discovered the important role of is like burning a organisms washed up on mats of ship-assisted colonization of islands in the Caribbean. Despite Renaissance painting its relatively small size, Trinidad, to cook a meal. for instance, has more species of anole lizards than the much larger Edward O. Wilson