2. Identify the type of data collected when describing the physical differences observed between the micro-photographs of normal and cancerous tissues.3. Identify the type of data collected when recording the amounts of cells in the different stages of the cell cycle.4. Identify and describe the experimental role of observing the normal tissue cells during this laboratory experience.Analysis:1. Based on the observations of the micro-photographs of normal and cancerous lung tissues, describe the main cause of the physical differences between the normal and cancerous cells.2. When studying cell division in tissue samples, scientists often calculate a mitotic index, which is the percentage of dividing cells in the sample. Explain whether the normal or cancerous tissue has a higher mitotic index.3. Identify which type of cancer that was observed has the most aggressive growth. Describe what shows that this is the most aggressive type.Conclusion: Decide whether the results supported or refuted thehypothesis. Explain using evidence from the results. Adapted from Glencoe Science’s Biology by Biggs, Alton et al. 2007 51
SECTION 3Sex-Linked Traits Virtual LabFigure 6.3 Drosophila red eyes and white eyesThe sex-linked trait of eye color in the fruit fly, Drosophila melanogaster.Photo by: Joachim Baran. Source: http://www.flickr.com/photos/25919479@N05/4581956293/! The purpose of this investigation is to explore the sex-linked Objectives:gene for eye color in Drosophila. This will involve performing 1. Construct and analyze Punnett squares for monohybrid geneticvarious fruit fly mating involving the eye-color trait and analyzingthe outcomes of the mating using Punnett squares. crosses involving sex-linked traits. 2. Perform Drosophila mating and analyze the offspring that result from each cross. 3. Explain why sex-linked traits appear more often in males than in females. 52
FEMALE PARENT MALE PARENT # OF RED-EYED # OF WHITE-EYED # OF RED-EYED # OF WHITE-EYED FEMALE FEMALE MALE MALE PHENOTYPE PHENOTYPE OFFSPRING OFFSPRING OFFSPRING OFFSPRINGPunnett Square Red Eyes Red Eyes Cross 1 (Heterozygous)Punnett Square White Eyes Red Eyes Cross 2 Mating 1 P Cross Mating 1F1 CrossMating 2P CrossMating 2F1 CrossTap the following link to open it in Safari. Then copy & paste it Background: Click on the “Information” button and TV in the virtualin the Puffin Web Browser app. Finally, tap the “Theater” button lab to answer the following questions in your own words with complete sentences. at the top left of the screen or find it in the menu . 1. Where are sex-linked traits found?http://goo.gl/pwDKpG 2. Who first observed sex-linked traits? 3. Did the crosses involving fruit fly eye color follow Mendel’s laws? 53
4. Which chromosome carries the allele for eye color in fruit flies? 4. Choose two of the F1 Generation, perform the cross and record5. How are the alleles for red and white-eye color indicated? your data in the table.Methods: On the biology lab home screen you will see a rack containing 5. Press “Reset” to repeat the process. If you did the Punnettjars of Drosophila for mating and a notebook to perform Punnett squares. squares first choose parents from the supply Drosophila to1. Recreate the data table from the previous page in the “Results” match of with one of the examples you did. If you are doing this part first choose a different set of flies to start with and record section of your lab report. your data in the table.You decide which of the following parts you should 6. When you have completed both generations, press “Return” tostart with. go back to the biology lab home screen.Part A – Mating the Drosophila. Part B – Punnett Squares.1. Examine the four jars on the top shelf that contain pure lines 1. Start by crossing a red-eyed male fly with a heterozygous red- (homozygous) of supply Drosophila. There is fruit-fly medium eyed female fly. (food) in the bottom of the jars. Each is labeled with a magnified drawing of the type of fly that is in that jar. Use the key at the 2. Fill in the Punnett square by dragging the appropriate picture to bottom of the rack to differentiate between male and female each box then click \"Check.\" Drosophila.2. Select a red-eyed male fly and white-eyed female fly from the 3. If you made any mistakes they will be highlighted for you. Start supply Drosophila containers on the top shelf and place them in by removing the incorrect offspring and replace them with the the P Generation Cross container then press “Mate and Sort”. correct images and press \"Check\" again. When all are correct3. Record the numbers of each type of offspring produced in the record the number of boxes that contain each phenotype in the table. data table. 4. Press “Reset” to perform a second cross. If you did the Drosophila mating first choose parents to match of with one of the examples you did. If you are doing this part first choose a different set of flies to start with and record your data in the table. --Continued-- 54
5. When you have completed both Punnett squares, press “Return” 6. Compare the results from the Punnett square and Drosophila to go back to the laboratory screen. mating whose parents match. Describe how similar or different the phenotype ratios and percentages are.Answer all of the following questions in your own words with completesentences. Make separate headings for the different sections. 7. Explain why recessive sex-linked traits appear more often in males than in females.Analysis: Spin-off:1. Which part was completed first: mating Drosophila in the laboratory or performing Punnett squares? Explain which part 1. Hemophilia, a blood disorder in humans, results from a sex- logically should be done first? linked recessive allele. Suppose that Helga’s mother does not have the allele for hemophilia and her father has the allele.2. Describe the phenotypes and genotypes of the parents from Helga marries a man with hemophilia. What is the probability Punnett square #2. that Helga’s children will develop the disorder? Describe the steps taken to determine the probability.3. Describe the offspring phenotype and genotype ratios of the offspring that resulted from crossing the parents in Punnett 2. Colorblindness results from a sex-linked recessive allele. square #2. Using these ratios, what percentage of the offspring Determine the genotypes of the offspring that result from a cross is white-eyed? What percentage of the offspring is red-eyed? between a color-blind male and a homozygous female who has normal vision. Describe the steps taken to determine the4. In a mating between a red-eyed male fruit fly and a genotypes of the offspring. heterozygous female, what percentage of the female offspring is expected to be carriers? Describe the steps taken to determine Conclusion: Decide if each of the objectives were accomplished. the percentage. Describe what specifically was done in the lab to complete the objectives or explain why they were not.5. In a mating between a red-eyed male fruit fly and a white-eyed female fruit fly, what percentage of the male offspring will have white eyes? Describe the steps taken to determine the percentage. Adapted from Glencoe Science’s Biology by Biggs, Alton et al. 2007 55
SECTION 4Population Biology Virtual LabFigure 6.4 Paramecium aurelia and Paramecium caudatumSource: http://www.flickr.com/photos/microagua/3309071169/ and http://www.flickr.com/photos/microagua/4550543500/! According to Darwin, one of the key elements that growth, but also will help to explain how availability of resourcescontributes to the evolution of a species, is competition for natural such as food, can be limiting for populations.resources. These resources can include food, water, light, space orshelter. In this investigation you will conduct an experiment and Tap the following link to open it in Safari. Then copy & paste itgrow two species of the protozoan Paramecium, alone and in the Puffin Web Browser app. Finally, tap the “Theater” buttontogether. You will then compare the growth rates of thepopulations of each species. This will not only demonstrate how at the top left of the screen or find it in the menu .competition for natural resources in the environment can affect http://goo.gl/YfEAIj 56
Background: Click the “Information” button to help answer the Methods:following questions in your own words with complete sentences.1. What are Paramecia? 1. Recreate the data table in the “Results” section of your lab2. In what type of environment can you expect to find report. Paramecium? 2. Observe the test tubes labeled 1, 2 and 3. There is rice in the test3. What are considered to be ideal conditions for Paramecium? tubes. The rice is food for bacteria, which in turn will be food4. What is meant by “exponential growth?” for the Paramecia. The two species of Paramecium do not prey5. What can cause exponential growth to stop? upon each other.6. What do scientists call the maximum number of individuals 3. Tap the bulb to fill the dropper with a sample of P. caudatum. found in an environment? Drag the dropper and place the sample in test tube 1. Repeat7. What is the difference between intraspecific and interspecific the process and place a sample of P. caudatum in test tube 3. competition? 4. Repeat the same process with the second dropper that contains8. Who was Gause? P. aurelia, placing samples in test tubes 2 and 3.9. What is Gause’s principle called?10.What does Gause’s principle state? 5. Tap the microscope on the counter at the back of the lab.11.What helps to reduce competition between different 6. Tap the box of clean microscope slides and then tap the samples populations of organisms? in the test tubes to set up wet mounts automatically.Hypothesis: Write a hypothesis predicting how the two species of 7. Drag each slide to the microscope to observe that sample. TheParamecium will grow alone and how they will grow when they are box to the right of the field of view tells you the sample numbergrown together. and gives you a key to the Paramecium species. Count how many individuals of each species there are in the field of view and record the data in the appropriate space on the data table. Note: Under the microscope you are looking at a .5 mL sample but in the table you need to record the number of cells in 1 mL. 8. Once you have observed all three slides and recorded the data, tap the “Clear Slides” button and then tap on the day calendar. 9. Repeat this process until your data table is filled. 57
Results: Recreate this data table in your lab report. capacity of the environment when it was grown alone? What shows this?DAY P. CAUDATUM P. AURELIA P. CAUDATUM P. AURELIA ALONE MIXED 2. Look at the graph you created in the Numbers app. On what day 0 ALONE MIXED did the Paramecium aurelia population reach the carrying 2 (CELLS/ML) (CELLS/ML) (CELLS/ML) (CELLS/ML) capacity of the environment when it was grown alone? What 4 shows this? 6 8 3. Explain the differences in the population growth patterns of the 10 two Paramecium species when grown alone. 12 14 4. What do the differences in the population growth patterns show 16 about how Paramecium aurelia uses available resources?Create a line graph using the Numbers app that shows the number 5. What type of competition (from the background questions)of each type of cell observed on each day. Refer to the instructions occurred in the experiment?in Chapter 3, Section 3. 6. Describe what happened when the Paramecium populations were mixed in the same test tube. Do the results support the principle of competitive exclusion? 7. Explain how this experiment demonstrates that no two species can occupy the same niche. 8. What two long-term effects of this competition are possible in the real world?Analysis: Answer the following questions in your own words with Conclusion: Decide whether the results supported or refuted thecomplete sentences. hypothesis. Explain using evidence from the results.1. Look at the graph you created in the Numbers app. On what day Adapted from Glencoe Science's Biology by Biggs, Alton et al. 2007 did the Paramecium caudatum population reach the carrying 58
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