Science 2 part 2

10. Animals are classified based on the presence or absence of a vertebral column. Whichof the following is NOT an invertebrate?a. fish c. spongeb. jellyfish d. starfishTest II. Matching Type. Match column A with column B. Write the letters only. A B1. The most abundant of all the animals on earth a. insects2. Animals with backbones b. echinoderms3. Invertebrates with spiny-skin c. sucker4. The substance that makes the exoskeleton of insects d. vertebrates5. Part of pearl oysters where the pearl is produced e. hydra6. Part of the squid used to capture prey f. mantle7. The part of sponges where water enters g. pores8. The freshwater form of Cnidaria h. tentacles9. The part of the tapeworm used for sucking i. radial10.The type of symmetry with a central disc where other parts j. chitin radiate Key to answers on page 35.Lesson 1. How Are Animals Classified? If you were asked to define what an animal is, you would probably say that animalsgenerally breathe, move, and eat, as most animals do. Yet we cannot define animals strictlyon the basis of these characteristics because not all animals inhale and exhale, even thoughwe know that all living cells respire. Not all animals move about. Not all of them havemouths and digestive systems. In spite of our lack of a completely satisfactory definition ofanimals, and in spite of living examples that do not fit neatly into any informal definition, wecan still categorize animals roughly as those organisms that breathe, move and eat. Before we discuss animals further, try to reflect on the following questions: What doanimals have in common? What are their differences? How are they classified or grouped?Find out the answers to these questions as you go over the modules. Are you ready now to explore the animal world? I'm sure you are! However, beforewe start, let's have a puzzle game about animals. Get set, go! -3-

What you will do Activity 1.1PUZZLE: W-H-A-T --AM--I? Here are some riddles. Choose your answer from the pictures below. Write youranswer on the blank after each statement. Microsoft Clip Art biology.nebrwesleyan.edu/courses/.../Ascaris_image.html W- H- A - T ---A - M ---I?  I am a bird but cannot fly. My body is too heavy to carry. I lay eggs that are big. What am I? __________  I am cylindrical. My home is your intestine. We share the foods that you eat. What am I? __________  I have tentacles and can swim. I sting my prey with my poison, many animals are afraid of me. What am I? __________  I am a reptile. I am long and can coil. I am a predator. I attack and eat chicks, frogs, birds and other animals. What am I? __________  I am flat, segmented and very long. My home is your intestine. We eat the same foods together. What am I? __________  My home is the sea. I look like a star. My skin is spiny. What am I? __________  I have ten legs and a flat shell or carapace. I am your favorite food. I am reddish when cooked. What am I? __________  My home is wet soil. My body is segmented. My best friends are farmers. What am I? __________  I live in the sea. I love to swim. I am the biggest of them all. I am a mammal like you. What am I? __________  My skin is soft and sticky. I can live both on land and in water. I lay eggs in the water. What am I? __________ Key to answers on page 35. -4-

Did you enjoy answering the riddles? Did you get a perfect score? If so, congratulations fora job well done! You are now about to begin studying the most diverse kingdom, the AnimalKingdom. This lesson involves the classification of both the vertebrate and invertebrateanimals. However, all the other lessons are focused on animals without backbones. As you go over the modules on animals, always remember that they all share thefollowing characteristics: 1. Animals cannot make their own food. They depend on other living organisms. 2. Animals digest their food. They cannot use proteins, fats and carbohydrates directly. 3. Many animals move from place to place. By moving around, they can find food, escape their enemies, find a better place to live and find mates. 4. Animals have many cells. Different cells carry out different functions such as digestion and reproduction. 5. Animal cells are eucaryotic. The cells have nucleus and organelles enclosed by a membrane.How to Classify Scientists have identified and named more or less 1 million species of animals. Someestimate that there are more or less 5 million more to identify and name. Have you everwondered why and how animals are grouped? If you have already finished the module onthe Diversity of Plants, I am sure that you are already familiar with classification or groupingof living things. In that module, an intensive discussion about classification is given. In this lesson, we will discuss how animals are classified on the basis of similaritiesand differences of body parts. Study the diagram below and see how the different animalsare grouped. Butterfly, fish, grasshoppers, spider birdAnimals without Animals with backbones backbones With 3 body regions With 2 body With gills Without gills(Moth & grasshopper) regions Fish Bird Butterfly and Spider grasshopper -5-

Now that you know the simple way of grouping animals let us move on to a moredetailed process.The Classification of Animals The major phyla of the animal kingdom are Porifera, Cnidaria, Platyhelminthes,Aschelminthes, Mollusca, Annelida, Arthropoda, Echinodermata and Chordata. Members ofthese phyla show the characteristics that we mentioned at the beginning, but when ascientist comes across a new animal, how does he/she begin to classify it? The first step is to examine if the animal has backbone or not. Animals withbackbones are called vertebrates. Examples of vertebrate animals are fishes, humans,whales and snakes. About 95% of all animals are invertebrates. Invertebrates are animalsthat do not have backbones. Sponges, jellyfish, worms, insects, and clams are allinvertebrates. The next thing that the scientist will look at is the arrangement of the bodyparts. This is called the animal's symmetry. Some animals have body parts arranged in acircle around a central point. These animals have radial symmetry. Sea anemones andstarfish have with radial symmetry. Most animals have bilateral symmetry. Look at themirror. Does the right side of your body look similar to the left side? Bilateral animals can bedivided into right and left halves by drawing an imaginary line down the length of its body.Some animals do not have definite shape and are called asymmetrical animals. Let’s see if you can now apply the principles you learned here in classification. Giventhe following animals, classify them using similarities in structure by completing the conceptmap after the diagram.Tapeworm EarthwormTurtle Monkey biology.nebrwesleyan.edu/courses/.../Ascaris_image.html -6-

What you will do Activity 1.2 Classifying AnimalsClassify the different animals listed in the box by answering the empty boxes below: Tapeworm, Earthworm, Fish MonkeyWith gills for gas Animals without exchange backbones Free-living form tapeworm Key to answers on page 36.Levels of Classification During the time of C. Linnaeus, he identified only 2 kingdoms, the Plant and Animalkingdoms. The system worked well until advances were made in classification. Biologistsnow use a six-kingdom system. In fact, an eight-kingdom system is now used in somebooks. The six - kingdom system includes Kingdom Protista, Achaebacteria, Eubacteria,Fungi, Plantae and Animalia. A kingdom is the largest group of classification. It issubdivided into several Phyla (phylum singular). Each phylum is divided into classes, whichare further divided into orders. Orders are divided into families, and families into genera andeach genus (plural genera) is divided into species. The species is the basic unit ofclassification. The lion, tiger and house cats belong to the same genus, Felis. Note thesimilarities among them.Naming of Organisms Can you imagine life without names? For example, if people were without names wewould need to completely describe each person to identify him/her and this could be verytedious. Names give people a quick and easy way of identification. -7-

Over two hundred years ago, a Swedish naturalist, Carolus Linnaeus, organized asimple naming system that we still follow today. He gave each animal species a scientificname. The scientific name is composed of two words, the genus name and the speciesname. This is called the binomial system of naming organisms. The names are in Latinwords. An example of this is the scientific name of our domestic cat, Felis domesticus. Thegenus name is Felis and the species name is domesticus. The advantage of using scientificnames is that there can be no confusion. A German scientist, an English scientist or aSpanish scientist will all know when they read Felis domesticus that what is referred to is acat. We are now through with the levels of classification including the naming oforganisms. Let's see how much you learned from the discussion. Try to answer these fewquestions. What you will do Self-Test 1.1Fill-in the blanks with the correct answer.__________ 1. Who was the first scientist who classified living things?__________ 2. Refers to animals without backbones__________ 3. Percent of animals without backbones__________ 4. The biggest unit of classification__________ 5. The smallest unit of classification Key to answers on page 36.Lesson 2. The Poriferans (Sponges) and Cnidarians This lesson is composed of the Sponges and Cnidarians. These are the first twolower phyla of the animal kingdom. The sponges, however, will be discussed first since theyrepresent a lower level of organization than Cnidarians.The Sponges (Pore-bearing Animals) Have you ever seen sponges? Well, if you haven’t seen one, try to do the activity onthe next page or refer to some diagrams to be familiar with them. Many Biology books havediagrams of these animals. Or you can refer to the diagram given in this module. -8-

What you will doActivity 2.1 How Do Sponges Look Like? If you live close to the sea, try to observe pore-bearing animals in their naturalhabitat. If possible do this during low tide when the shoreline is wide. Do not forget to equipyourself with the following:a. glass bottom box or any improvised oneb. trowelc. forceps or gloves Your purpose here is to observe and not to collect. You see, we discouragecollection of specimens. We want to preserve these animals in their natural habitats. Useyour glass bottom box or goggles to locate the animals. Do you see pore-bearing animals?They are of different colors and with numerous pores or openings throughout the bodysurface. They are usually attached to a substrate and are steady in one place. They are assoft as the sponges that you use in washing you dishes. Write your observations in anotebook and try to answer the table below.Name of specimen ______________________________1. Where found ______________________________2. Moving/non-moving ______________________________3. Organ for movement ______________________________4. Color ______________________________5. Appearance / texture ______________________________6. Use to man ______________________________If you do not live close to the sea, refer to the diagram of the different sponges below: www.greengabbro.net/photoblog/archives/000713.php Figure 1a. Sponges -9-

Years ago, scientists thought sponges were plants. Why do you think this was so?They appear like plants more than like animals because we often associate animals withmobility. Sponges are steady or fixed in one place and are attached to a substrate. Thereare around 3,000 species of sponges. Most common of these are the bath sponges.Porous animals or sponges are considered as the simplest multi-cellular animals. Theseanimals and their relatives have a body wall with tiny holes, or pores - thousands of them!They are usually found in the sea. Pore-bearing animals have two layers of cells, an outerand an inner layer. The food is captured by these cells and is taken in by \"engulfing\". Theyprimarily feed on particles suspended in water, planktons, and some bacteria. Notice thatthey have a wide opening known as the osculum or mouth where food passes. The food isdigested in the spongocoel or cavity, which is equivalent to our stomach. http://www.anselm.edu/homepage/jpitocch/genbios/33-03-SpongeAnatomy-L.gif Figure 1b. Parts of a Sponge Care should be taken in handling these animals since the body contains thousands ofspicules or skeletons, which can cause irritations on the skin. These spicules arecomposed of siliceous materials or calcium carbonate. Look at the diagram of thespicules in Figure 1. This is how they look like under the microscope. The Venus Flower Basket is an example of a beautiful sponge composed ofsiliceous spicules. Aside from these spicules, the body is also composed of collagen andfibrils of collagen collectively known as spongin. They all give support to the sponge andprevent it from collapsing. This makes the sponge ideal as a scrubbing material. - 10 -

The Cnidarians Just like the sponges, if you live close to the shore, you will also find the Cnidarians.In some books, they are popularly referred to as the coelenterates or bag-shaped animals.Cnidarians include many animals with brilliant colors and unusual shapes. Delicate jellyfishfloat in ocean currents. Brightly colored sea anemones cling to rocks, looking more likeunderwater flowers than animals. These beautiful and fascinating animals are found all overthe world, but most species live only in the sea. Here in our country, our seas abound withthis group of animals. We have beautiful sea anemones and jellyfishes. If you live close to the sea, you can easily examine these invertebrates. However, instudying this group of animals, you have to be very careful not to provoke or intimidate theorganisms. They might hurt you.What you will doActivity 2.2 How Do Cnidarians Look Like? If you live close to the sea, try to observe the cnidarians in their natural habitat. Ifpossible do this during low tide. Do not forget to equip yourself with the following:a. glass bottom box or any improvised oneb. trowelc. forceps and gloves Your purpose here is to observe and not to collect. You see, we discouragecollection of specimens. We want to preserve these animals in their natural habitats. Useyour glass bottom box or goggles to locate the animals. Do you see the beautifully coloredsea anemones? They are stationary but with very movable tentacles. If you disturb thesurroundings, their tendency is to retract and hide their tentacles. Do not touch them forthey might hurt your hand with stinging cells. Other cnidarians that are steady or sessile arethe corals. How many types of corals do you see? Try to look for other cnidarians. See ifjellyfishes are available. If you see one, do not go very close to it. It might sting/hurt you.Just observe the body movement. Unlike the sea anemones, they are very motile. Afteryour observations, fill-up the following:Name of specimen ______________________________1. Where found ______________________________2. Moving/non-moving ______________________________3. Organ for movement ______________________________4. Color ______________________________5. Appearance / texture ______________________________6. Use to man ______________________________ - 11 -

Write your other observations in a notebook. Now, look at the diagram below. These are examples of Cnidarians. Have you seenthe actual specimens?Hydra Sea Anemone Jellyfish search.gallery.yahoo.com/search/corbis?p=jellyfish Figure 2. CnidariansCharacteristics of Cnidarians There are more than 9,000 different species of Cnidarians, the Latin term forstinging cells. Most species are marine in habitat while few are freshwater forms. Themost common freshwater species is Hydra. This is only around 5 mm long. Somemembers are bag-shaped, like the sea anemones. Their bodies are hollow with oneopening at the top, which is the mouth or osculum. Inside the body is a cavity known as thegastro vascular where extracellular digestion of food takes place. A ring or circulartentacles can shoot out stingers or nematocysts that can poison and paralyze anotherorganism. The tentacles then capture the prey and break down the food with the help ofdigestive substances. Examples of these are the sea anemones and the polyps of thecorals. Have you ever asked why corals are considered as animals? Well, the corals thatyou have at home are only \"secretions\" or \"skeletons\" formed by the animals thatformerly occupied it. The former occupants are the polyps, which are already dead. One of the most colorful members of this phylum are the jellyfishes. They are cup-shaped, free-swimming, and with tentacles. Some jellyfishes are harmless while others canbe very harmful. - 12 -

Know this: The most harmful species of jellyfish is Chironex flickerii. This is a jellyfish present in the tropical seas of Australia. This species have poisonous stings that can kill man in 3 to 20 minutes after the attack. Jellyfishes flourish during summertime when seawater is warm. They love to stay inwarm places. Presence of unusual number of jellyfishes in a certain place can also indicatethermal pollution of the waters. To be more familiar with the jellyfish, try to examine theillustration below. It represents the life cycle of a jellyfish. The prominent part of the cycle isthe medusa, the free-swimming form and the most familiar to us. The polyps are small andcould hardly be seen. www.dnr.state.sc.us/marine/pub/seasscience/jellyfi.html Figure 3. Life Cycle of a Jellyfish What you will do Self-Test 2.1 1. What are spicules and what are they for? 2. Trace the pathway of water in the body of sponges. 3. Discuss the life cycle of a jellyfish. 4. What makes some jellyfishes dangerous? 5. What are tentacles for in polyps? Key to answers on page 36. - 13 -

Lesson 3. The Flatworm, Roundworm and Segmented Worm This lesson is about the three groups of worms - the flatworm, roundworm and thesegmented worm. In the previous two lessons we have discussed animal classification,the sponges, and the cnidarians. Based on the complexity of structures, sponges andcnidarians are followed by the flatworms, roundworms and segmented worms. Theseinvertebrates will be the next topic of our discussion. The animals that you will most likely think of when you hear the word worm is theearthworm - the worm that you see after the rain in pavements or in the soil. Sometimes,they are even used as bait by fishermen. You probably wouldn't think immediately oftapeworms or any other types of worms. Just what is a worm? Worms are invertebrateswith soft-bodies and bilateral symmetry. They have tissues, organs and organ systems.Have you ever experienced deworming a puppy? If so, you must have seen some of theworms that will be mentioned here. Not all worms are parasitic. Some are free living andsome are even helpful. In this lesson, only one representative will be discussed in eachgroup. They are the worms that may primarily affect your health. Do this: Look for a slaughterhouse near your place and bring forceps or gloves and bottles half-filled with 70% ethyl alcohol. 1. Ask the help of a butcher and collect the available worms in the slaughterhouse using the forceps and place them in your collecting bottles. 2. Take note of the part of the body where you got the worm. 3. Bring the specimens home and study them. Try to compare them with the diagram below. Which of these worms did you collect in the slaughterhouse?Tapeworm Ascaris Earthworm biology.nebrwesleyan.edu/courses/.../Ascaris_image.html Figure 4. The Three Types of Worm - 14 -

The Flatworms The first groups of worms that we will discuss are the flatworms. As their commonnames suggest, flatworms are flattened dorso-ventrally and soft-bodied. Some intestinaltapeworms may grow up to 100 feet (30 meters). All flat worms belong to PhylumPlatyhelminthes. This phylum is divided into three classes or groups: Turbellaria (e.gPlanaria), Cestoda (e.g tapeworm) and Trematoda. (e.g fluke). Look at figure 4. It shows of the three groups of flatworms but only the tapewormswill be discussed here.Tapeworms To start off with our discussion about tapeworms, examine closely your specimen. What you will do Activity 3.1 If you were able to collect pork tapeworms from the slaughterhouse, put thetapeworm on a dissecting pan and examine its parts. Use forceps or dissecting needle indoing this. First, measure your specimen. How long is your specimen? Starting from theanterior part of the body, look for the scolex or head. What parts do you see in the scolex?What are they for? Now count the number of body segments or proglottids. How many are there? If youdo not have the actual specimen, study the illustration of a mature tapeworm below. Key to answers on page 36. Focus on the diagram next page and see how the pork tapeworm, Taenia solium caninfect man. Tapeworms use their hooks and suckers to attach themselves to the intestine ofthe host organism. They do not have mouth or a digestive system. Their body is composedof several segments with the head or scolex as the first anterior segment. The othersegments or proglottids produce eggs and sperms. Most of the time, the eggs are fertilizedwithin the same segments. After fertilization, the eggs are now called as \"embryonated\"eggs. Once a segment is filled with fertilized eggs, it breaks off and passes out. - 15 -

http://www.lander.edu/rsfox/310taeniaLab.html Figure 5. Tapeworm One way of ensuring you won't get infected by pork tapeworm is to eat only well-cooked meat at 56 degrees centigrade and above. Other ways to control pork tapewormsinclude sanitary disposal of human feces, inspecting meat, feeding hogs or pigs properly,and treating people who are positive for taeniasis, the infection caused by tapeworms. Challenge! Use any Biology book or refer to a diagram and make a poster showing the life cycle of a pork tapeworm. Cooking meat at 56 degrees centigrade and above is enough to kill the cysticerci inthe measly (infected with larval worms) pork or freezing it at -5 degrees centigrade for atleast one week. Some of the symptoms of tapeworm infection are loss of appetite, diarrhea,dizziness, abdominal pains, headache and intestinal obstruction. - 16 -

Assignment: Go around your neighborhood or barangay and do the following: 1. To help avoid tapeworm infection, check if all houses are provided with sanitary toilets. 2. Observe if stray pigs roam around the place. 3. If so, find out the measures taken by the municipal health officer to discourage people from allowing pigs to go astray. 4. As a concerned citizen of your locality, what can you contribute to avoid infection among the citizenry?The Roundworms Members of this phylum are found almost everywhere. There are more than half amillion species of roundworms under Phylum Nematoda. There maybe a million in akilogram of soil! They can be found in freshwater, seawater, and in or on plants, humansand other organisms. Before we start with our discussion, try to recall when was the last time you took adeworming medicine? Was it the other year? last year? or this year? Well, if you just hadit, that's good. Getting rid of all these parasitic worms is healthful. Although there are anumber of different roundworms like pinworms, hookworm, and trichina worm. We will justconcentrate on the Ascaris. These are very common to children especially in rural areas.Poor hygiene and mishandling of food are common causes of infection. Let us now start bydiscussing Ascaris, the most common roundworm. What you will do Activity 3.2 1. Get some ascaris specimens from a near slaughter house. 2. Put the ascaris specimens that you got from the slaughterhouse in a dissecting pan and examine the parts. You will notice that their bodies are waxy. Why do you think this is so? 3. Compare the shape of the worms. Do they all have the same shape? Males are usually smaller and with a bent posterior end, while females are bigger and with a straight end. Males use the bent end for copulation or mating. 4. In case no specimens are available, you can refer to Figure 6 on the next page and compare the body parts. Key to answers on page 37. - 17 -

Just like the other parasitic worms that we have discussed, the roundworm can alsobe transferred from one host to another. Infection occurs when “embryonated” eggs areswallowed with contaminated food and water. They hatch in the duodenum of the intestine,where the young penetrate the mucosa and sub-mucosa and enter the lymphatics orvenules. After passing through the right side of the heart, they enter the pulmonarycirculation and breakout of the capillaries into the air spaces. Many worms get lost duringthis migration and accumulate in almost every organ of the body, causing acute tissuereaction. This is the reason why sometimes some worms come out from the mouth, ears ornose of children with heavy infection. Some worms that are swallowed pass through thestomach and into the small intestine, where they mature. Within 60-65 days after beingswallowed, they begin producing eggs. Look at the male and female ascaris in the diagram below. How do they differ?What is the use of the bent end or spicule in the male ascaris? Figure 6. Male and Female Ascaris Things to remember about ascaris worms: 1. Eggs in food and water are ingested by host. 2. Eggs hatch in the small intestine. 3. Larvae enter blood vessels and are carried to the lungs. 4. Larvae or young ascaris travel to the throat and are swallowed. 5. Adult ascaris worms live in the small intestine. 6. Eggs leave host in feces and can live up to ten years in the soil if conditions are favorable. - 18 -

Have you heard that...? … Ascaris eggs are resistant to chemicals. They can still be embryonated successfully in 2% formalin solution and in 50% hydrochloric acid, nitric acid, sulfuric acid, acetic acid and in other inhospitable conditions. This is due to the extraordinary chemical resistance of the lipid layer of the ascaris eggshell. Ascaris eggs can live for 10 years in the soil. Its longevity contributes to the survival of the parasite.The Segmented Worms The worms that you see on sidewalks and driveways after a hard rain or on theground near the water faucets belong to Phylum Annelida. Most annelids are free-living.The word annelid is a Greek word meaning \"little rings\". There are over 6,000 species ofsegmented worms. Annelids are worldwide in distribution, occurring in the sea, freshwaterand terrestrial soil. Some marine annelids live quietly in tubes or burrow into the bottom ofmud or sand. Some feed on organic matter in the mud, others are filter feeders, while someare predators. Examples of segmented worms are earthworms, leeches and the beautifulfan worms. In this lesson, we will discuss the different groups of segmented worms but our focuswill be on the more common representative, the earthworm.Earthworm Leech Nereis www.greengabbro.net/photoblog/archives/000713.php Figure 7. Segmented Worms - 19 -

The common groups are Polychaeta, Oligochaeta and Hirudinae. Out of thesethree, we will discuss only the Oligocahaeta ( earthworms).The Earthworm Go to your backyard and try to locate a moist and wet place most probably close to awater source. Do not forget to bring a small garden trowel or knife to dig into the soil. What you will do Activity 3.3Materials needed: Trowel, gloves, forceps collecting bottle and 70% alcohol or 10% formalin solutionProcedure: 1. Go to the garden and bring the materials with you. 2. Look for a place that is wet and moist all the time. 3. Use the trowel and try to dig slowly into the soil. 4. Notice that you will encounter a lot of earthworms. These are noticeable through their segmented bodies. 5. Put your earthworm specimens inside the collecting jars with 70% alcohol. Three or four medium-sized earthworm specimens will do. 6. Once at home, transfer your specimens to a bottle cap with white background and examine closely the parts. We will study only the external parts. You start from the anterior (front or head) to the posterior (back or tail) part of the body. Count the number of body segments. How many are there? Are all the segments of equal sizes? 7. From the anterior to around one third of the body, you will encounter an enlarged segment that is girdle-like. This is the clitellum. Can you see it? This is used in reproduction. Now, focus on the last segment where the anus is located. Is it similar to the othersegments? What do you think this is for?Answer the following: 1. In what part of your garden did you find the earthworms? 2. What part of the body is found in the first segment? 3. More or less, how many segments did you find in the earthworm? 4. Are the segments of equal sizes? - 20 -

5. What is the girdle-like band on the body of the eathworms? What is it for? Key to answers on page 37. The digestive system of the earthworm is made up of crop, gizzard, and intestine.The soil eaten by the earthworm moves to the crop for storage. Behind the crop is astructure, the gizzard, that grinds the soil. In the intestine that follows, food is broken downand absorbed by the blood. Undigested soil and waste materials leave the worm throughthe anus. http://sps.k12.ar.us/massengale/earthworm_dissection.htm Figure 8a. External Parts of an Earthworm http://sps.k12.ar.us/massengale/earthworm_dissection.htm Figure 8b. Cross-section of an Earthworm - 21 -

Do you know? … that earthworms eat soil? While they burrow through the soil they are actually eating it. Earthworms get their energy from the bits of leaves and other plant and animal materials mixed with the soil. What you will do Self-Test 3.1 1. What are parasitic worms? Free-living worms? 2. Which one has more hosts-tapeworms or ascaris? 3. What do earthworms eat? 4. How could you be infected with Ascaris? 5. What part of the digestive tube of earthworms functions for grinding food? Key to answers on page 37.Lesson 4. The Soft-Bodied and Joint-Legged Animals This lesson includes two groups of animals, the soft-bodied animals and the joint-legged animals. The soft-bodied animals are also called molluscs. They have softbodies, some of which are protected by one or two shells while other members do not havevalves. The joint-legged animals are those with joint appendages and segments known asthe arthopods.The Soft-Bodied Animals Have you ever collected shells, watched a snail crawl, or had squid for dinner? Thenyou must be familiar with mollusks. The word mollusk is a Greek word meaning \" soft\".Mollusks are soft-bodied invertebrates that usually have shells. They are found on land, infreshwater and in salt-water habitats. In our study of soft-bodied animals, we will just limit our discussion to the three mostcommon types such as the univalves, bivalves and cephalopods. However, the diagramwill include all the other members such as chiton, squid, and octopus. Most molluscs havesoft bodies covered by a hard shell. Covering the soft body is the mantle. The mantle is athin layer of tissue that secretes the shell, or protects the body if the mollusk does not havea shell. Between the soft- body and the mantle is the space called the mantle cavity.Inside it are the gills, organs that exchange oxygen and carbon dioxide with water. The - 22 -

body organs of mollusks are located in an area called the visceral mass. The mantle coversthe visceral mass. Finally, all mollusks have a muscular foot used for movement. http://sps.k12.ar.us/massengale/wpe8.gif Figure 9a. Parts of a Soft-bodied Animal (Clam) Look at the diagram that follows. It includes all the other members of PhylumMollusca.Chiton Snail LimpetWhelk Shell Squid Octopus www.medinavalleycentre.org.uk/limpet_grazing.htm Figure 9b. Molluscs - 23 -

To be more familiar with these soft-bodied animals, do this simple activity:FIND OUT! Use a hand lens (if necessary) to observe a clam. You can get the clam in themarket near your place. Count the number of rings or bands on the shell. Count the largetop point called the crown as one ring. Are all the bands of the same width? Can you tellwhat the width of the bands may indicate? Get actual specimens of clams, oysters and mussels (tahong). What is common toall of them? If your specimens are alive, notice how they close and open their shells.Except for the oyster, how do they move from one place to another?If you answered: - No, because each band signifies the abundance of food during the growing season. - They all have 2 valves (bivalves). - They move by using their foot. Congratulations! All your answers are correct Have you heard? …that pearl oyster produce pearls? Pearls are formed in many bivalves. Pearls are secreted by the mantle in layers around a grain of sand or other particles trapped between the mantle and the shell of pearl oysters. What you will do Activity 4.1Prepare the following materials: Squid, forceps, scissors, chopping boardProcedure: 1. Get a fresh specimen of a squid and study its external parts. 2. Notice that it has two eyes on the lateral sides. 3. Examine the tentacles. They have suckers with teeth. Two of the tentacles are larger than the others. This holds the victim and brings it to its mouth. 4. Locate the mouth with the teeth. The tentacles bring the captured food into the mouth. - 24 -

5. Notice the fins. These are useful in swimming. The mantle covers most of the body. 6. When you prepare squid for cooking. One thing that you remove is the elongated cellophane-like part inside. Do you know what this is? It is called as the pen. This serves for buoyancy. 7. Notice the presence of the ink sac. What is this for?Answer the following: 1. How do squids capture their food/prey? 2. Why do squids and octopuses release ink into their surroundings? Key to answers on page 37. Do you know? …that squids can swim at more than 60 meters per second? They can move faster than an octopus. They also have the longest nerve fiber. It is 50-100 times longer than any nerve fiber found in man.The Joint-Legged Animals Have you ever been attacked by arthropods? If so, I’m sure they could be insects,crabs, centipedes, millipedes, spider or maybe a scorpion. All of these mentioned arearthropods or joint-legged animals. Arthropods make up around 75% of all animals in theanimal kingdom. They are well adapted to almost every environment on Earth. Appendages are structures that grow from the main body. Your arms and legs areappendages. The jointed appendages of arthropods include the legs, the antennae, theclaws and the pinchers. In this lesson, you will be introduced to the different groups of joint-legged animals. To be more familiar with all its members, study the diagram on the nextpage. The organisms shown are all members of Phylum Arthropoda. - 25 -

www.dannesdjur.com/einsect20.shtml Figure 10. Arthropods For a start, try to acquaint yourself with the arthropods in the field. A meadow orgrassland would be ideal for this activity. If no grassland is nearby, the backyard of yourhouse will do. What you will do Activity 4.2Prepare the following materials: insect net forceps trowel wide-mouthed bottle or small plastic bags The purpose of this activity is to observe and not necessarily to collect (except forsome). Therefore, you are not supposed to damage or destroy the animals. You canrelease them later. Try also to look for specimens in the soil. Use a trowel for this purpose.Take note of the arthropods that you collect and list them in your notebook. After you are through, fill the blank spaces below: - 26 -

Name of specimen ______________________________1. Symmetry ______________________________2. No. of body regions ______________________________3. No of legs ______________________________4. Interesting features ______________________________5. Where found ______________________________6. Locomotory organs ______________________________Answer the following questions:1. How many types of arthropods did you observe?2. What is the most common among the arthropods that you observed?3. Where did you find them?4. Are your specimens moving or not?5. What organs do they use? Key to answers on page 37. Now, let us start our discussion of the arthropods. Aside from the presence ofappendages, arthropods also possess an external covering called the exoskeleton. Theexoskeleton covers, supports and protects the body. This exoskeleton is a non-livingstructure that cannot grow as the animal grows. This is periodically replaced by a new oneand the process is called molting. The cast-off integument is called the exuviae, and thearthropod undergoing molting is called an instar. The new skeleton is soft and takes time toharden. You must have observed a crab with soft shell. It has just molted and the new shellhasn't hardened yet. The old exoskeleton has been replaced. Molting indicates growthamong arthropods.Insects You must be very familiar with insects. Insects are the most abundant and mostwidely distributed member of the phylum. No other group of animals has as many membersas class Insecta. More than 700,000 species of insects have been described and about300,000 of these alone are beetles! Scientists describe thousands more each year. Let'slook at the features that distinguish insects from other arthropods and also find out whatmake them so diverse among all the animals on earth. Insects have three body regions, thehead, thorax and abdomen (please refer Figure 11). They are also provided with three pairsof legs (hexapod).Have You Heard?A honeybee colony sometimes contains 30,000 – 40,000workers. - 27 -

The capacity of insects to survive is due partly to its high chance of adaptability andgreat variations in lifestyles. Insects live in almost every habitat, from tropical forests tofrigid areas. Their ability to fly has also allowed them to transfer to new, unexploitedhabitat, and to escape from predators. It has also helped them to disperse and enabledthem to have greater access to food and more desirable environment. Some insects canmultiply rapidly. Take the flies, for example. Some flies can produce new generation everyeight to ten days just like the Drosophila flies. In the case of certain insects, like the termites,the female can lay more than one million eggs during her life time. A queen bee on the otherhand, can lay more or less one million eggs during her life time. That’s about 1000 eggs perday. Have You Heard? One of the differences between social ants and termites is that termites depend on “child labor”. In a termite colony, nymphs work. In an ant colony, the larvae are cared for by the adult workers. If you can collect a grasshopper nearby, you can study the parts of an insect usingthe guide below:What you will doActivity 4.3Get the following materials: dissecting pan, etherized grasshopper and dissecting needlePut the etherized grasshopper in a dissecting pan and locate the following parts:a. antennae e. legsb. eyes f. wingsc. head g. abdomend. thorax1. Count the number of body regions. How many are there?2. Starting from the head try to look at the appendages. How many antennae do you see? How many eyes? Insects' eyes are called compound eyes. The mouthpart is composed of several appendages. They have mandibles, and other parts, which we will not discuss in detail.3. The second body region, the thorax has 3 pairs of legs and two pairs of wings. - 28 -

4. The abdomen is segmented in insects, but there are no appendages similar to those of the thorax. As you go over the parts, you can refer to the Figure 11. Key to answers on page 37. Figure 11. External Parts of a Grasshopper What you will do Self-Test 4.1True or False. Write the answer on the blank.__________1. A squid can swim faster than an octopus.__________2. Tahong is a univalve.__________3. Legs and wings are examples of appendages.__________4. All insects molt.__________5. Insects have two body regions. Key to answers on page 37.Lesson 5. The Spiny-Skinned Animals - 29 -

You may be familiar with the spiny-skinned animals, the echinoderms. These arefound along the coastal area and in school laboratory or natural museums. Mostechinoderms are marine animals. Examples of echinoderms are starfish, sea urchins, sanddollar, sea cucumber and sea lilies. Some of their remains maybe washed up on the beach.Echinos is a Greek word meaning spiny and derm means skin. So, echinoderm meansspinny -skinned animals. The spiny part refers to the spines that cover the outside of these animals. Theirbodies are supported and protected by an internal skeleton made of calcium plates. Theplates are covered by a thin, spiny skin. They are very colorful. There are about 5,000species of echinoderms. Some echinoderms are edible just like the sea cucumber whichare converted into trepang, a Chinese delicacy. The gonads of some sea urchins are alsoused for food. What you will do Activity 5.1For a start, if you live close to the shore, try to do this: 1. First make sure that it is low tide so that you can have an access to the deeper (knee high) part of the shoreline. 2. From here, try to observe invertebrates that are spiny-skinned. The most familiar you could probably see are the starfishes. They have 5 arms radiating from the center. 3. Try to lift one live starfish and observe the tube feet at the ventral side of the animal. The tube feet are used for movement of the animal. Observe other echinoderms like the sea urchin. Be very careful in handling this animal. They are spiny and some are with poisonous spines. 4. Other echinoderms that you will encounter along the sandy-rocky side of the shore are the brittle stars and sand dollars. 5. Look for sea cucumbers. These have leathery skin and are soft.Based on your observations from this simple activity, try to answer the following: 1. How many types of echinoderms did you see? 2. What features do all echinoderms have in common? 3. How do echinoderms move and get their food? Key to answers on page 38. Now, in case you have doubts with your answers, try to study the diagram below.These are examples of echinoderms. Are you familiar with them? - 30 -

www.greengabbro.net/photoblog/archives/000713.php Figure 12. EchinodermsStarfishes Seastars or starfishes,demonstrate the basic features of echinoderms' structures andfunctions. Sea stars are widely distributed long the intertidal zones. Sometimes largenumbers of them may group together on rocks. They also live among muddy or sandybottoms and coral reefs. Their color varies. Some are orange or red, while others are blue.Are you familiar with the seastar on Figure 13?Dorsal Side Ventral Side www.fishprofiles.com/interactive/forums/thread.asp?id=21662 Figure 13. Dorsal and Ventral View of a Starfish The dorsal and ventral sides of a starfish are shown on Figure 13. Note the radialsymmetry and five arms. Most starfishes are pentamerous or with five arms. The armshave tubefeet on the ventral side that help in movement through action of the watervascular system (WVS). The mouth is located on the vetral side, at the center. Opposite to - 31 -

this, on the ventral side is the anus. They are mostly carnivorous and feed on mollusks likeclams and oysters.Congratulations! At last you are through with the module. I hope you enjoyed your journeyto the invertebrate world.What you will doSelf-Test 5.1Matching Type. Match the sentences in column A with the words in column B.AB1. Term used for echinoderms with 5 arms a. Acanthaster planci2. Meaning of echinos b. spiny-skinned3. Also called the crown of thorns c. Trepang4. A Chinese delicacy d. Ambulacral5. The grove where tubefeet stick out e. Pentamerous Key to answers on page 38. Let’s Summarize1. There are more or less 1 million different species of animals.2. There are seven major units or levels of classification with the kingdom as the largest unit and the species as the basic unit of classification.3. Originally, there were only two kingdoms established by Linnaeus now, some books use the eight- kingdom system.4. There are nine major phyla of the animal kingdom. The simplest groups are the pore-bearing animals and the most complex are the mammals.5. C. Linnaeus introduced the binomial system of classification. In this system, he gave two names to an organism, the genus and the species name.6. Sponges are the simplest group of animals. Only tissues are present. The osculum serves as their mouth. This is a large opening on top of the sponges. Sponges produce skeletons in the form of spongin and spicules.7. Cnidarians are soft- bodied animals with stinging tentacles arranged in circle. They are mostly marine in habitat with only a few like the Hydra that is terrestrial. They have tentacles to capture their prey. They use stinging cells to paralyze their prey.8. Flat worms are soft and dorso-ventrally flattened. Planaria is an example of a free-living form. Tapeworm and flukes are parasitic flatworms. Pork tapeworm - 32 -

involves two hosts, man and pig. The adult tapeworm is found in man while the larvae are found in the pig.9. The male ascaris has a bent posterior part while the female ascaris has a straight posterior end.10. Ascaris lumbricoides involves two hosts, man and pigs.11. The adult lives in the intestine of man while eggs and larvae are found in the intestine of pigs. These larvae will later on migrate to the muscles of the pig.12. Earthworms love to live in wet and moist places because they use their wet skin for gas exchange.13. Earthworms feed on soil and other decaying waste materials.14. There are four groups of mollusks: the monoplacophorans, univalves, the bivalves and the cephalopods. Some bivalves like the oyster pearl produce pearls from the foreign materials that get inside the mantle of the animal squids. They also have the longest nerve fiber. It is 50-100 times longer than any found in man.15. Cephalopods produce ink for body defense against enemies.16. Arthropods are characterized by an exoskeleton of chitin, jointed appendages, and a segmented body.17. In order to grow, arthropods must periodically remove/change its old exoskeleton, the process is called molting.18. Insects are the most abundant of all the arthropods. They are also widely distributed because of their ability to fly.19. Insects have three body regions - the head, the thorax and abdomen.20. Echinoderms are spiny-skinned animals.21. They move by means of the tube feet propelled by the water vascular system.22. Sea cucumbers look different from the other groups due to the absence of hard covering or hard ossicles.PosttestTest I. Multiple Choice. Choose the letter of your answer and write it on your answersheet.1. Which among the following animals is NOT spiny-skinned?a. bivalve c. sea cucumberb. brittle star d. sea urchin2. Which of the following is a primary characteristic of sponges?a. antennae c. suckersb. pores d. tentacles3. In the binomial system of classification, organisms are given two names. What is it composed of? - 33 -

a. family and genus name c. order and genus nameb. species and genus name d. local and international name4. Which among the following animals has many pores or openings in its body?a. Ascaris c. spongeb. earthworm d. tapeworm5. What is another name for mollusks with two valves?a. bivalve c. trivalveb. gastropod d. univalve6. Which among the following animals has different canal systems?a. earthworm c. spongeb. sea anemone d. tape worm7. All of the following are parasitic worms except:a. ascaris c. hookwormsb. earthworm d. tapeworms8. Jellyfishes are noted for their powerful tentacles. What are their tentacles for? a. for excretion b. for digestion c. for reproduction d. for capturing food and defense for excretion9. The number of body regions in insects is:a. one c. threeb. two d. four10. Animals are classified based on the presence or absence of a vertebral column. Whichof the following is NOT an invertebrate?a. fish c. spongeb. jellyfish d. starfishTest II. Matching Type. Match column A with column B. Write the letters only. A B1. Presence of two valves a. grasshopper2. The cavity found inside the sponges b. spongocoel3. A freshwater group of Cnidarians c. Hydrozoa4. Attaches tapeworms to the intestinal wall d. Ascaris5. Presence of tube feet e. Spider6. Where eggs are hatched in earthworms f. Tapeworms7. Male worm with spicule g. Starfish8. Causes the disease called taeniasis h. Clitellum - 34 -

9. With three body regions i. Hooks10. With two body regions j. bivalvia Key to answers on page 38.Key to AnswersPretest 6. d 7. a Test I. Multiple choice 8. d 1. c 9. c 2. d 10.b 3. b 4. c 6. h 5. c 7. g 8. e Test II. Matching Type 9. c 1. a 10. i 2. d 3. b 4. j 5. fLesson 1 6. Starfish 7. CrabActivity 1.1 8. Earthworm 9. Whale 1. Ostrich 10. Frog 2. Ascaris 3. Jellyfish Tapeworm, Earthworm, 4. Snake Fish, Monkey 5. Tapeworm - 35 -Activity 1.2

Animals with backbones Animals without backbonesWith gills for gas With lungs for Parasitic Free-living form exchange gas exchangeFish Monkey Tapeworm EarthwormSelf-Test 1.1 1. Linnaeus 2. Invertebrates 3. 95% 4. Kingdom 5. SpeciesLesson 2Self-Test 2.1 1. Spicules are for defense/protection. 2. Pores, and ultimately to the osculum 3. It starts from a zygote, then the zygote becomes a ciliated planula larvae, which later on becomes a polyp. The polyp undergoes strobilation forming the young medusa which later on will become either a male or female jellyfish. 4. Nematocytes are provided with stinging cells. 5. For catching the prey/foodLesson 3Activity 3.1 Probable answers: 1. Approx. 2 meters 2. Scolex is provided with hooks and suckers. The hooks are for attachment, while the suckers are for sucking nutrients. 3. Approx. 200 segmentsActivity 3.2 - 36 -

In case your answer in question no. 2 is: as protection for the acidic environmentinside the digestive tube, you are correct! In question number 3 the answer is: No, the malehas a bent posterior part while female a straight end.Activity 3.3 1. damp soil 2. mouth or prostomium 3. 75 segments 4. yes 5. clittellum, for hatching eggsSelf-Test 3.1 1. Parasitic worms depend on the host, while free-living looks for their own food. 2. Tapeworms 3. Soil mixed with dried leaves and other materials 4. Improper sanitation and eating infected food 5. GizzardLesson 4Activity 4.1 1. The arms or tentacles sweep the food / prey towards the mouth. 2. They release ink for defense purposes against their predators.Activity 4.2Possible answers: 1. I observed four groups of arthropods. 2. The most common ones are insects. 3. I found them attached to trees, under stones and some in the soil. 4. They are very mobile. 5. They have legs for locomotion.Activity 4.3 1. 3 body regions 2. 1 pair 3. 1 pair of compound eyesSelf-Test 4.1 1. True 2. False 3. True - 37 -

4. True5. FalseLesson 5Activity 5.1Possible answers:1. More or less 5 groups2. Spinny-skinned and radial symmetry3. Through the water vascular system (WVS) and tubefeetSelf-Test 5.11. e2. b3. a4. c5. dPosttestTest I. Multiple choice 6. d1. d 7. a2. d 8. d3. b 9. c4. c 10.b5. cTest II. Matching Type 6. h1. j 7. d2. b 8. f3. c 9. a4. i 10.e5. gReferencesBooks:Balzer, L., Collins, A., Goodson, P., Lauer, L., Slesmik, I. & Alexander, G. (1984). Introduction to biology. Glenview, Illinois: Scott Foresman and Co. - 38 -

Biggs, A., Daniel, L. & Ortleb, P. (1994). Life science. Westerville, OH: Merrill Publishing Co., Mcmillan/McGraw – Hill.Campbell, N.A. (1996). Biology. (4th ed.) California: Benjamin Cummings Publishing Company.Mader, S.A. (1998). Biology. (6th ed.) Boston, USA: WCB McGraw-Hill Companies, Inc.Mauseth, James T. (1996). Botany. Florida, USA: Harcourt Brace and Company.Miller, K.R. & Levine, J. (1991). Biology. Massachusetts, USA: Prentice Hall.Stern, K.R. (1994). Introductory plant biology. USA: Wm. C. Brown Publishers, Inc.Wong, H.K. & Dolmatz, M.S. (1986). Biology; The key ideas. New York, USA: Globe Book Company, Inc.Electronic Sources:Retrieved January 7, 2005 from www.abdn.ac.uk/~nhi708/treasure/venu/ sciencekit.com/category.asp_Q_c_E_432269&sid=marketleap biology.nebrwesleyan.edu/courses/.../Ascaris_image.html www.dannesdjur.com/einsect20.shtml www.cyberdive.org/bonaire1003/source/friendly_squid.html www.medinavalleycentre.org.uk/limpet_grazing.htm www.greengabbro.net/photoblog/archives/000713.php www.fishprofiles.com/interactive/forums/thread.asp?id=21662 carlytedra.healthyplace2.com/custom.html search.gallery.yahoo.com/search/corbis?p=jellyfish - 39 -

Module 18 Animals with Backbones What this module is about This is another module on animals, and this time, it deals with animals withbackbones. Animals with backbones fall under Phylum Chordata. Only around 5% of allanimals on earth are with backbones. Members of this phylum have notochord. Thenotochord is a structure that supports the body of a young chordate. This structure maypersist only during the embryonic stage of the animal or until the adult stage. In someanimals, this is replaced by the hard backbone or vertebral column in the adult stage. There are 5 groups of vertebrates namely: Pisces(Fishes), Amphibia, Reptilia,Aves and Mammalia. Each group or class will be discussed in separate lesssons except forbirds and mammals which are combined since both of them are warm-blooded animals.The lessons are as follows:  Lesson 1 – Pisces (Fishes)  Lesson 2 – Amphibians  Lesson 3 – Reptiles  Lesson 4 – Birds and Mammals What you are expected to learn After our discussion about animals with backbones, you are expected to: 1. Identify the major characteristics of animals with backbones. 2. Describe the characteristics of the five groups of vertebrates. 3. Identify fishes, amphibians, reptiles, birds and mammals. 4. Identify the adaptions that enable the fishes, amphibians, reptiles, birds and mammals to live in their natural habitat. 5. Distinguish among monotremes, marsupials and placental mammals.

How to learn from this module In order to achieve the objectives of this module successfully, you have to rememberthe following: 1. Read and follow the instructions carefully. 2. Answer the pretest. 3. Take down notes and record points for clarification. 4. Take the posttest and check your answers with the key at the end of the module. 5. Try to obtain at least a 70% level of proficiency in the tests.What to do before (Pretest)Multiple Choice. Choose the letter of the correct answer. Write the chosen letter on aseparate sheet of paper.1. Vertebrates are animals with vertebral column. Which of the following is NOT avertebrate?a. fish c. snailb. parrot d. turtle2. Cold blooded animals are those that can not regulate their body temperature. Which ofthe following is a cold-blooded animal?a. anteater c. lizardb. eagle d. monkey3. Turtles live in water. Where do they lay their eggs?a. deep portion of the sea c. pits along the sandb. in seagrasses d. subtidal zone4. In what part of the mother kangaroo does the young grow and develop?a. placenta c. pouchb. uterus d. fallopian tube5. The following are the characteristics of amphibians EXCEPT:a. with moist skin c. warm-bloodedb. can lay eggs d. can live both on land and water6. Which among the following birds cannot fly?a. eagle c. ostrichb. hornbill d. owl -2-

7. What do frogs use for gas exchange when on land?a. lungs c. skinb. kidneys d. snout8. Marsupials are animals with pouches for the young. Which of the following is amarsupial?a. kangaroo c. monkeyb. lion d. tiger9. Mammals are vertebartes with mammary glands. These glands supply the younga. hormones c. saltsb. milk d. water10. What part of the mother monkey is important in the development of the embryo?a. cervix c. placentab. ovary d. vagina11. Which of this is an egg-laying mammal? c. platypus a. koala d. tarsier b. monkey12. Which of the following animals do NOT have scales?a. fishes c. roostersb. monkey d. snakes13. Warm-blooded animals can adapt to changes in environmental temperature. Which ofthe following animals is NOT warm-blooded?a. cheetah c. leopardb. crocodile d. man14. What part of the reptiles can be used in making leather shoes and bags?a. bones c. skinb. claws d. tail15. How many percent of all animals are vertebrates?a. 5% c. 15%b. 10% d. 20% -3-

16. Which of the following is used by frogs for gas exchange when underwater?a. gills c. skinb. lungs d. All of the above17. Which is the most diverse group of vertebrates?a. birds c. mammalsb. fish d. reptiles18. To maintain normal body temperature, birds have:a. beak c. feathersb. claws d. scales19. Amphibians have limbs used for movement. How many limbs do they have?a. I pair c. 3 pairsb. 2 pairs d. 4 pairs20. The structure that attaches the embryo to the placentaa. uterus c. amniotic fluidb. allantois d. umbilical cord Before you start with the lesson proper, try to answer the crossword puzzle preparedfor you. The puzzle is designed to check your background about animals with backbones. 12 3 45 6 89 7 -4-

CROSSWORD 1: VertebratesACROSS: 1. Class of jawless fishes 3. Class of four-limbed vertebrates that produce milk to nourish their young 4. A vertebrate that has feathers and wings for forelimbs 7. Class of vertebrates with feathers 8. Rod-shaped structure that serves as the primary axial skeleton of vertebrates during embryonic development or even up to adulthood in some cases 10. Animals that have a vertebral column for axial supportDOWN: 2. An animal, such as a frog, that has naked skin and can live both in water and on land 5. Cold-blooded animals that have scaly skin 6. Class of sharks and rays 9. Substance that makes up the skeleton of sharks and rays Key to answers on page 23.Was it easy? If you got a perfect score, congratulations! More power as you move on!Lesson 1. Fishes (Jawless Fishes, Jawed Fishes, Bony Fishes) When you hear the word fishes, what is the first thing that comes into your mind?Goldfish? Milkfish? Coralline fish? Or the canned sardines in the kitchen? Well, there aremore than 30,000 different species of fishes – even more than all the other species ofvertebrates combined! Would you believe that 80% of all these species of fishes are foundin Philippine waters? This is how rich our seas are. The richest marine habitat in ourcountry is the Tubbataha Reef found in Sulu seas. It is our showcase to the world. Itharbors almost all the different species of fishes in the world. There are three groups of fishes, namely, the jawless fishes, the cartilaginous fishesand the bony fishes.Jawless Fishes Look at the illustration on the next page. This is a diagram of a lamprey and hagfish.They are examples of \"jawless\" fishes belonging to Class Agnatha. These jawless fisheshave round mouths, and long tube-like bodies covered with slimy skin with no scales.Fishes in this class have very flexible bodies made of cartilage. A cartilage is a tough,flexible tissue not as hard as a bone. Feel your ears and the tip of your nose; these are alsomade of cartilage. -5-

Hagfish Lamphrey Figure 1. Hagfish and Lamprey www.zoo.ufl.edu/couses/Vertzoo/lab_bonyfish2.html www. Metafilter.com/mefi/2565 Jawless fishes do not have eyes. Most of them are found in freshwater habitat.Lampreys are examples of these. They use their round mouth with short tentacles to attachto other fish by suction. They cut into the fish with tooth-like structures and feed on its bloodand body fluids. They are parasitic.We will now proceed with the second group of fishes, the cartilaginous fishes.Cartilaginous Fish Stingray Shark Figure 2. Cartilaginous Fisheswww.beekypoo.com/LasVegas200203/imagepages/image41.htm plusinfo.jeonju.ac.kr/photos/Animals Are you familiar with the illustrations above? These are common in the market.Skates, sharks and rays are members of Class chondricthyes. They have skeletons madeup of cartilage just like the jawless fishes. Unlike jawless fish, however, chondricthyes havemovable jaws and scales. Still remember the movie, the Jaws? You will easily recognizethese if you have watched it. This movie features how powerful the jaws/teeth of sharksare. Their scales resemble vertebrate teeth and cause their skin to feel like sand paper.Most sand papers especially in the early times were made from the skin of sharks. -6-

Do you know …? … that although whales and dolphins live in water, they are not fish? They have lungs, they breathe air and are mammals. Now that you are through with the jawless and cartilaginous fishes, let us move on tothe bony fishes, the fishes you are most familiar with.Bony Fish Bony fishes make up ClassOsteicthyes. Fishes that belong to thisclass have skeletons made of bones.About 95 percent of all species of fishbelong to this class. Examine Figure 3and Figure 4. These are examples ofbony fishes. Figure 4 is already labeledfor you. This will serve as your guide asyou study the parts of the actualspecimen. Are you familiar with the fishin the diagram? Figure 3. A carp fish www.akwafoto.aip.pl/fotoreport/krakow2/mariae.php What you will do Activity 1.11. Get a sample of a fish, preferably bangus or tilapia. Study the external parts. I'm sure you are very familiar with these vertebrates since you often see them on your dining table.2. Starting from the anterior part, look for the mouth, nostrils (two small openings) and the two eyes.3. Try to locate the gills, which are partly covered by the bony operculum. The operculum is a structure that closes and opens to release water from the gills. The gills are important for gas exchange.4. Notice the presence of the dorsal, pelvic, pectoral and anal fins. All these are provided with fin rays that serve as support.5. From here, you have the main body usually covered with scales in the most posterior part, which is the tail or caudal fin. -7-

If you have some problems with the instructions, refer to Figure 4 showing the partsof the fish. Operculum Figure 4. External Anatomy of a Bony Fish sites.state.pa.us/Fish/education/catalog/fishpartsanswerAnswer the following: 1. Why are the gills reddish in color? What are they for? 2. How many types of fins do you see? What are they for? 3. What do you think is the use of tails in fishes? Key to answers on page 24. Do not forget these facts about fishes. They have:  Skeletons made up of bones  Bodies covered with scales  Fins for swimming  Gills for breathing  Two chambered heart and are cold - blooded -8-

What you will doSelf-Test 1.1Matching Type. Match the phrase in column A with the item it describes in column B.Write the letters only. A B1. Cartilaginous, jawed fish a. swim bladder2. Jawless fish b. gill3. A structure used for gas exchange in fishes c. hagfish4. The Greek word meaning bone d. sharks5. Helps make the fish bouyant e. osteon6. Bones that cover the gills f. ichthye7. Fins used to propel the fish g. bony fishes8. Supports the fins in fishes h. lamprey9. Cylindrical with round mouth i. fin rays10. The largest group of fishes j. Operculum k. caudal or tail fin Key to answers on page 24.Lessson 2. The Amphibians (Frogs, Toads, Salamanders and Newts) During rainy seasons, you might have noticed tadpoles in your pond. After a while,the tadpoles have probably metamorphosed into an adult frog. There are around 4,000different species of amphibians in the world. These are the smallest among the vertebrates.They range from 1 cm to 170 centimeters in length. Let’s begin this lesson by doing this simple activity: What you will do Activity 2.1Try this: 1. Get one frog or toad from your garden or near a riverbank. Sometimes, toads are more common than frogs. They are usually plenty during the rainy season. 2. Put your specimen in a collecting bottle and add chloroform or ether to immobilize -9-

your specimen or if you don’t have these chemicals, you can just pith/probe the brain with a dissecting needle. This can immobilize your specimen. 3. Now study the parts. If your specimen is a toad, you might note that it has warty and rough skin, including a square-shaped skull. If it is a frog, you will note that it is smooth-skinned. 4. Start with the head. Locate the mouth, nostrils, eyes and the round tympanic membrane for hearing. 5. Shift to the main body mass. There are four legs attached. Hind legs are bigger since they are used for jumping. Do you find a tail? As you locate the external partsin your specimen, you can refer to thediagram of a frog on the right. It canserve as your guide. Figure 5. External Parts of the Frogwww.scchristian.pvt.k12.ia.us/bvanderb/frog.html Frogs, toads and salamanders are amphibians. They have moist, smooth skin, orwarty skin without scales. They can breathe through their skin. Oxygen and carbon dioxidecan be exchanged through the skin and the lining of the mouth. Amphibians also have verysmall sac-like lungs in the chest cavity that are used for breathing on land. These groups ofanimals are also called cold-blooded which means that their body temperature changesdepending on the temperature of the environment. Do you know? … that frogs can stay buried in the mud for several months when the temperature is very low in temperate countries? They are less active and need little amount of food. Special fat bodies keep them alive until after they can feed again in the spring. Some frogs are poisonous while others are edible. Frogs are a delicacy in someparts of the world and even here in our country. Their skin can also be used in industrieslike in wallet and bag making. Some scientific researches also use frogs and frog allies likethe newts in regenerating lost body parts. The studies suggest ways by which lost limbs orbirth defects in humans can be remedied. - 10 -

Try to answer the simple review test prepared for you. Make sure to do your best. What you will do Self-Test 2.1Direction. Write the word true if the statement is correct, and false if it is incorrect._________1. All amphibians can live both on land and in water._________2. Amphibians are cold-blooded._________3. Amphibians have scales._________4. Amphibians can use their moist skin for gas exchange._________5. The forelegs in frogs are bigger than the hind legs. Key to answers on page 24.Lesson 3. The Reptiles (Lizards, Snakes, Turtles and Crocodiles) When children think of reptiles, they would probably think of dinosaurs, and other bigreptiles of long ago. They always see these reptiles on television shows and magazines.However, when you think of reptiles, you will probably think of snakes moving through thegrass, lizards climbing up a trunk of a tree. You may also think of a big crocodile floatingnoiselessly in a pool and a tortoise slowly eating a meal. All these animals are reptiles.What are reptiles? Reptiles are cold-blooded vertebrate with dry, scaly skin and a specialtype of egg adaptations that enable them to live their entire life out of water. In this lessonwe will discuss reptiles in general, their characteristics and other features. Examine thediagram below showing reptilian representatives. Are you familiar with all of them?Turtle Lizard Snake Figure 6. Turtle, Snake, and Lizard www.all-creatures.org/pics/turtles-shl-4.html www.runningsranch.org/Lizards.html In some ways, reptiles resemble amphibians. Both are cold-blooded which meansthat their body temperature depends on the temperature of their surroundings. However, - 11 -

reptiles are better adapted to life on land. For example, reptilian skin is dry and leatheryand is often covered with thick protective scales. This type of body covering helps preventloss of body water in dry environments. The disadvantage of this type is that the toughscaly layer of skin must be changed periodically in a process called molting.TurtlesAre you familiar with the animal infigure 7? It is a sea turtle locally known aspawikan. Do you know how turtles differfrom a tortoise? Well, turtles are found orlive in water, while tortoise live on land.Do you know that the meat of a sea turtle isedible? It is considered a delicacy in thecoastal towns of Cebu, Sulu and EasternLuzon where it is found. However, eatingturtle meat is discouraged since the animalis near to extinction. Figure 7. A sea turtle diskusjonsforum.no/akvariet/printthread.php?t=12317 Do you know? … why sea turtles leave the water to lay their eggs on land? It is because they can't get oxygen from the water the way fish can. Once their eggs are laid, they never come to see them again! If the eggs hatch in water, the baby turtles would drown right away. In fact, if a sea turtle were to lay her eggs in the sea, the turtles would die even before they could hatch. That would happen because even the eggs needed air to breathe. Turtles make up a very successful order of animals. They can be found in almostevery continent and in most of the world's oceans. The body of a turtle is covered by a hardshell both on top and at the bottom. Most turtles can withdraw into their shell for protection.Turtles have no teeth and use their beaks to feed on insects,worms, fish and plants. So, donot be afraid of the turtles. Remember they do not have teeth and they don't bite! You will now proceed to the next group, the lizards and snakes.Lizards and Snakes Go back to the illustration of the different reptiles. Do you see the snakes andlizards? Snakes and lizards make up the largest group of reptiles. If you are not familiarwith them, find a means to see the actual specimens of these animals. You can see them - 12 -

placed in natural museums or live in Zoos and other reserved areas. Some are sold in petshops although selling of lizards and snakes is supposedly banned now. Do you know? … that snake oils are used as medicine? ANCROD is an ingredient in the venom of pit vipers being studied as a possible medicine to prevent human stroke. ANCROD is a substance that stops blood from clotting. Doctors say that a correct dosage of ANCROD can prevent the damage of strokes caused by blood clots that block blood vessels in the brain of man. The venom is collected from the snakes by pressing their jaw against the container. Are you afraid of snakes? Many people are. Maybe this is because some snakes,such as rattle snakes are poisonous and dangerous. But most snakes are not poisonous.In fact snakes are helpful to humans because they eat pests like insects, rats and mice.Snakes are meat eaters. They do not have legs, eyelids and external ears. Some snakeswrap around and trap their prey. Others inject their prey with poison venom. Many snakesfeed on rodents like rats and help control their populations.The last group of reptiles that we are going to discuss are the crocodiles.Crocodiles Look at the illustration on the right. Are you Figure 7. A Crocodilefamiliar with crocodiles? Have you seen one? If so,where? Were you frightened? In Manila zoo we the-i.org/pic_fauna/08have several specimens of live crocodiles. InPalawan, there is already a crocodile farm found inPuerto Princessa. The purpose of this farm is toprotect the crocodiles and increase their number.Crocodiles and alligators are among the world'slargest living reptiles. They are carnivorous andsome species can grow up to 7 meters in lengthwith a mass of around 1,000 kilograms. Theseanimals live mostly in the tropics where the climateremains warm the whole year round. Crocodileshave long, slender snouts and are very aggressive. - 13 -