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1) A population of bats feeds on flying insects. Some of these bats have a gene that results in much stronger flight muscles than those of the other bats in the area. Explain how this variation could lead to evolutionary change within this species of bat. In your answer, be sure to include an explanation of:
• competition within the bat population
• survival of various individuals within the bat population
• how the frequency of the trait for stronger flight muscles would be expected to change within the bat population over time
Examples:
— Bats with the variation for stronger flight muscles would most likely catch more flying insects than bats without the gene. — More bats possessing the gene for stronger flight muscles would survive than those without. — Over time, more bats would possess the variation for stronger flight muscles.
2) Explain why comparing the vein patterns of several leaves is a less reliable means of determining the evolutionary relationship between two plants than using gel electrophoresis.
– Chemical similarities are more reliable than structural similarities. – Electrophoresis shows chemical similarities, which are more reliable. – Many unrelated plants have a similar vein pattern.
Base your answer for questions 3 to 4 on the information below and on your knowledge of biology.
Two adaptations of the monarch butterfly that aid in its survival are the production of a certain chemical and a distinctive coloration that other animals can easily recognize. When a monarch butterfly is eaten, the presence of the chemical results in a bad taste to the predator.
Although the viceroy butterfly does not contain the chemical that tastes bad to a predator, it does resemble the monarch in size, shape, and coloration.
3) Explain how the combination of this chemical and the distinctive coloration aid in the survival of the monarch butterfly.
Example: — The predator gets a bad taste from the monarch butterfly and then recognizes other members of that species and does not eat them.
4) How do the characteristics of the viceroy butterfly aid in its survival?
Example: — Since the viceroy butterfly resembles the monarch, predators that have tasted a monarch butterfly do not eat viceroy butterflies.
5) Two cultures, each containing a different species of bacteria, were exposed to the same antibiotic. Explain how, after exposure to this antibiotic, the population of one species of bacteria could increase while the population of the other species of bacteria decreased or was eliminated.
Examples: — Organisms with antibiotic resistance would survive and reproduce. Others without resistance would decrease in number.
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An insect pest known as the medfly significantly reduced the orange crop in California. Pesticides were used to control the medfly. Using the concept of natural selection, explain how the continued use of a certain pesticide may become ineffective in controlling this fly. Your answer must include the concepts of:
• variation
• adaptive value of a variation (adaptation)
• survival
• reproduction
Examples: Some medflies have a variation that provides resistance to pesticide. ‘When the pesticide is present, those flies with the favorable variation will survive to reproduce and pass the variation to offspring. A variety of medfly resistant to the pesticide will result.
7) Growers of fruit trees have always had problems with insects. Insects can cause visible damage to fruits, making them less appealing to consumers. As a result of this damage, much of the fruit cannot be sold. Insecticides have been useful for controlling these insects, but, in recent years, some insecticides have been much less effective. In some cases, insecticides do nothing to stop the insect attacks.
Provide a biological explanation for this loss of effectiveness of the insecticides. In your answer, be sure to:
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identify the original event that resulted in the evolution of insecticide resistance in some insects
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explain why the percentage of resistant insects in the population has increased
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describe one alternative form of insect control, other than using a different insecticide, that fruit growers could use to protect their crops from insect attack
Responses include, but are not limited to: • A mutation (or genetic change) probably occurred that led to the resistance to the insecticide
• The percentage of resistant insects in the population has increased over the years because they survived when the insecticide was used, and were then able to reproduce and pass on the resistance
• release natural predators of the insects; the release of large numbers of sterile males of insect species that damage fruits; provide conditions that help predators of the insects live in the area; genetically engineer insect-resistant plants
Base your answer for questions 8 to 9 on the information below and on your knowledge of biology.
The three great lakes in Africa (Victoria, Tanganyika, and Malawi) contain a greater number of fish species than any other lakes in the world. Lake Malawi alone has 200 species of cichlid fish. The diversity of cichlid species in these African lakes could have been caused by changes in water level over thousands of years. According to one hypothesis, at one time the three lakes were connected as one large lake and all the cichlids could interbreed. When the water level fell, groups of cichlids were isolated in smaller lakes as shown in the diagram. Over time, the groups of cichlids developed genetic differences. When the water levels rose again, the isolated populations were brought back into contact. Due to significant genetic differences, these populations were unable to interbreed. Variations in water level over thousands of years resulted in today's diversity of cich-lid species.
8) As the water level of the lakes changed, many species of cichlids survived while others became extinct. State why some species survived while others became extinct.
Examples: – Some species are better adapted to the environment. – Some species have greater ability to compete for food or escape predators or breed. – natural selection
9) Each cichlid population is genetically different from the other cichlid populations. State one reason for these genetic differences.
Examples: – evolution – meiosis – sexual reproduction – recombination during fertilization – cross-over – mutations – natural selection / isolation
10) Certain insects are kept under control by sterilizing the males with x rays so that sperm production stops. Explain how this technique reduces the survival of this insect species.
Responses include, but are not limited to: If sperm production stops, then eggs cannot be fertilized; It reduces genetic variation by limiting the number of males that can produce offspring; Without reproduction no species can survive.
11) A hawk has a genetic trait that gives it much better eyesight than other hawks of the same species in the same area. Explain how this could lead to evolutionary change within this species of hawk over a long period of time. In your answer, be sure to include an explanation of:
a. competition within the hawk population
b. survival of various individuals in the population
c. how the frequency of the better-eyesight trait would be expected to change over time within the population
d. what would most likely happen to the hawks having the better-eyesight trait if they also had unusually weak wing muscles
a. Examples: — The hawk with the better eyesight would compete more successfully. — The hawks with the better eyesight would have a better chance of obtaining food.
b. Examples: — Individuals with the better-eyesight trait would have a better chance to survive.
c. Examples: — The frequency of the better-eyesight trait would increase.
d. Examples: — If the hawks have better eyesight and weak wings, they will not have the same advantage as those with better eyesight and normal wings.
Base your answer for questions 12 to 14 on the information below and on your knowledge of biology.
Based on their analysis of the differences in amino acid sequences of one kind of protein, scientists prepared the evolutionary tree shown below.
12) Older systems of classification always placed penguins, chickens, ducks, and pigeons in the bird group and turtles and snakes in the reptile group. Does this diagram support the older system of classification? Explain your answer.
Examples: — Snakes are in their own group, rather than grouped with turtles. — Turtles are on the same branch as the birds. — Snakes have one kind of protein that is very different from that found in turtles and birds.
13) According to this diagram, the DNA of which pair of organisms would show the greatest similarity?
A) penguin and turtle
B) horse and donkey
C) snake and tuna
D) turtle and rabbit
14) According to this diagram, is the pig more closely related to the dog or the kangaroo? Justify your answer.
Examples: — separated more recently — closer together on the tree — have a more recent common ancestor — The protein in the pig is more similar to that in the dog.
Base your answer on the information below and on your knowledge of biology.
Gaurs, which are large oxlike animals found in South Asia, have been hunted for sport for many generations. Most recently, as human populations have increased, the gaur’s habitats of forests, bamboo jungles, and grasslands have dwindled. The gaur is now considered an endangered species.
Scientists have succeeded in preserving endangered species by cloning. Recently, a gaur was cloned and the resulting embryo was placed inside a domestic cow, which then gave birth to a baby gaur.
15) State one way, other than cloning, that gaurs might be saved from extinction.
Examples: — preserving the habitats in which they live — restricting hunting of gaurs