Name: Date: Period: Unit 1 Test: Microevolution (Original Test) Ms. OK, AP Biology,

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1 Name: Date: Period: Unit 1 Test: Microevolution (Original Test) Ms. OK, AP Biology, General Directions: Use your time effectively, working as quickly as you can without losing accuracy. Do not spend too much time on any one question. Go on to other questions and come back to the ones you have not answered if you have time. Multiple Choice: Each of the questions or incomplete statements below is followed by four suggested answers or completions. Select the answer that is best in each case and enter the appropriate letter in the corresponding space on the scantron. When you have completed part A, you should continue on to part B. Topic #1 1. Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses? (A) Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits so they were selected against. (B) Natural selection cannot account for losses, only for new structures. (C) The ancestors of these organisms experienced harmful mutations that forced them to find new habitats that these species had not previously used. (D) Natural selection accounts for these losses by the principle of inheritance of acquired characteristics (proposed by Lamarck) 2. The rough-skinned newt produces a toxin that can kill predators. Scientists have observed that some garter snakes can feed on the newts because they have a natural resistance to the toxin. In areas where populations of roughskinned newts and garter snakes interact, which of the following predictions is best supported by evolutionary theory? (A) The garter snakes with resistance to the toxin will successfully reproduce and pass the trait on to their offspring. (B) The garter snakes without resistance to the toxin will acquire resistance by increasing the rate at which they feed on the newts. (C) The rough-skinned newts that produce low levels of toxin will also develop camouflage adaptations that allow them to hide from the garter snakes. (D) The newts will start making a toxin to which all garter snakes are susceptible. In 2006, scientists discovered fossilized skeletons of an animal with several interesting features, which they named Tiktaalik. Fossil evidence indicated that Tiktaalik not only had scales, fins, and gills, but also had lungs, a full set of ribs, and limb bones to support the animal s weight. The illustration on the next page is a representation of what Tiktaalik likely looked like based on the fossil evidence found by the scientists. 3. Which of the following statements is incorrect regarding the Tiktaalik fossils? (A) They possess some features found in aquatic organisms. (B) They possess some features found in terrestrial organisms. (C) They provide evidence that terrestrial organisms evolved from aquatic ancestors. (D) They provide evidence that terrestrial traits arose and evolved very quickly in evolutionary time.

2 Partial amino acid sequences for a particular protein in three animal species are shown below. Each of the letters in the sequence stand for an amino acid. Species Gallus varius Crocodylus niloticus Gallus gallus Amino acid sequence QHEPHERKRM SHDPAQQKRL QHEPHKRKRM 4. Which of the following statements best explains how these sequence data are evidence for evolution? (A) All species create the amino acid sequences of their proteins in a similar way. (B) The species that are most closely related have the most similar amino acid sequences. (C) Individual organisms acquire changes in their amino acid sequences over their lifetimes. (D) The organisms that evolved at the same time in geologic history have identical amino acid sequences. The diagram below illustrates a field of mice hunted by the same hawk over a period of 3 months. 5. Which of the following statements is supported by the information in the diagram? (A) The allele for dark fur color in the mice appeared when the hawk began preying on the mice. (B) The fitness of the light colored mice decreases over time as the hawk preys upon them (C) The light mice were able to mutate to become more fit in their environment (D) The hawk s fitness increases as the allele frequency for mouse fur color changes. Topic #2 6. A population of squirrels is preyed on by small hawks. The smaller squirrels can escape into burrows. The larger squirrels can fight off the hawks. After several generations, the squirrels in the area tend to be very small or very large. What process is responsible for this outcome, and what would you predict would be its effect on allele frequencies? (A) Directional selection; the allele for small squirrel size is not favored over the allele for large squirrel size (B) Disruptive selection; the allele for large squirrel size is favored over the allele for small squirrel size (C) Stabilizing selection; the alleles for large and small squirrel size are found in equal frequency in the population (D) Disruptive selection; the alleles for large and small squirrel size are favored equally in the population 7. Suppose the hawks are removed from the environment and a new predator is introduced that can only digest small squirrels. What will be the outcome, and what process is responsible for this outcome? (A) Medium and large squirrels will become more common; directional selection (B) Small squirrels will become more common; directional selection (C) Medium squirrels will become more common; stabilizing selection (D) Small and large squirrels will become more common; stabilizing selection

3 8. Female cardinals are more likely to mate with male cardinals with bright red coloration. However, bright color makes males more likely to be noticed by predators. Which statement below best describes the relationship between sexual selection and natural selection in this example? (A) Bright coloration will become more common in the male population, even though bright males will be less likely to survive to reproductive age. (B) Dull coloration will become more common in the male population, even though females will not choose dull males as mates. (C) Medium bright coloration will become more common in the male population because some females will mate with these males and they will be more likely to survive to reproductive age. (D) Medium bright coloration will become less common in the male population because females will not mate with these males and they will be less likely to survive to reproductive age. 9. Male gorillas fight to gain access to females. The largest, strongest males are more likely to reproduce. Females, however, do not fight for access to males. Over time, how will the phenotypes of males and females compare? (A) Males will be much larger in size than females; this is called sexual dimorphism. (B) Males will be much larger in size than females; this is called disruptive selection. (C) Males and females will both be large in size; this is called sexual dimorphism. (D) Males and females will both be large in size; this is called disruptive selection. Topic #3 10. Blacktip sharks normally reproduce sexually. In 2008, researchers at an aquarium in Virginia discovered that a blacktip female shark in their collection reproduced asexually through the process of parthenogenesis, in which no sperm is required to fertilize the egg. One disadvantage to this method of reproduction is: (A) increased gene recombinations (B) decreased number of eggs used (C) decreased genetic diversity within the species (D) increased genetic fitness 11. A species that lacks the variation necessary to adapt to a changing environment is more likely to (A) develop many mutated cells (B) become extinct over time (C) develop resistance to diseases (D) become more genetically diverse 12. Brassica oleracea was a European wild plant from which early farmers were able to produce cabbage, cauliflower, broccoli, kohlrabi, kale, and Brussels sprouts. Farmers were able to artificially select it with such success because the native plant (A) experienced genetic drift in the original population (B) had a great deal of genetic variation in the original population (C) experienced gene flow in the original population (D) was available in all those different forms to begin with 13. Suppose a mutation found in several members of a population prevents pairs of homologous chromosomes from attaching and crossing over during meiosis (see the image of successful crossing over to the right). How will this affect the population? (A) Offspring of individuals with the mutation will have fewer chromosomes than their parents. (B) Offspring of individuals with the mutation will have more chromosomes than their parents. (C) There will be more genetic variation within the population as a result of this mutation. (D) There will be less genetic variation within the population, as crossing over is a normal process that creates new gene combinations.

4 Topic #4 14. In those parts of equatorial Africa, where the malaria parasite is most common, the sickle-cell allele constitutes 20% of the hemoglobin alleles in the human gene pool. If this population were in equilibrium and the sickle-cell allele is recessive, what proportion of the population should have the sickle cell phenotype? (A) 32% (B) 80% (C) 4% (D) 20% 15. In a Hardy-Weinberg population with two alleles, A and a, the frequency of allele a is 0.3. What can be assumed about this population, provided that random mating occurs and the population is very large? (A) The frequency of a will remain the same over a period of time, with little fluctuation. (B) The frequency of heterozygotes is (C) The population reproduces asexually so allele frequency does not change. (D) The percentage of homozygous dominant organisms is 42%. A hypothetical population of 500 cats has two alleles, T and t, for a gene that codes for tail length. The table below presents the phenotype of cats with each possible genotype, as well as the number of individuals in the population with each genotype. Assume that this population is in Hardy-Weinberg equilibrium. Recall that the Hardy-Weinberg equation is: p 2 + 2pq +q 2 = What is the frequency of cats with short tails in this population? (A).32 (B).48 (C).4 (D) If a population is found to be in Hardy-Weinberg equilibrium, which of the following can be assumed about the population? (A) Mating occurs at random (B) Sexual selection of attractive males occurs (C) Gene flow has occurred (D) Allele frequencies fluctuate wildly from generation to generation 18. In a population of ground-dwelling birds, the allele for short beaks is dominant to that of long beaks. During a particularly harsh summer, a drought kills off most of the vegetation the birds utilize as food, and leaves behind insects which inhabit the cracks in the ground that result from the drought. Which of the following correctly describes both the mechanism of evolution and the effect it will have on allele frequencies for the beak trait? (A) Genetic drift; the frequency of the long beak allele increases (B) Natural selection; the frequency of the long beak allele increases (C) Gene flow; the frequency of the short beak allele decreases (D) Genetic drift; the frequency of the short beak allele increases

5 Calculations: For the following three calculations questions, identify the given and asked for information before starting your calculations. Show all work on this page and record your answer in the grid-in provided. You will be given instructions about how to complete the grid-in. 1. In a randomly breeding population of mice, 640 had black fur and 360 brown fur. Black fur is dominant to brown fur. This population is in Hardy Weinberg Equilibrium. Calculate the frequency of the recessive allele for this population. Express your answer to the nearest tenth. 2. In a population of turtles, the small shell trait is controlled by a recessive allele (t), and large shell is controlled by a dominant allele (T). There are 810 small-shelled turtles in a population of 1000 turtles. Calculate the actual number of turtles with the heterozygous genotype. Express your answer to the nearest whole number. 3. A scientist and her colleagues collected rock pocket mice across 35 kilometers of the Arizona Sonoran Desert that included both dark, rocky lava outcrops and light rocky granite areas. Substrate color and coat color frequencies were recorded for each location. Each site was separated from any of the others by at least 8 kilometers. A total of 225 mice were trapped. Her data is summarized by the table below: Calculate the frequency of light-colored mice captured on the dark-colored substrates out of the total number of mice captured on the dark-colored substrates. Express your answer to the nearest hundredth.

6 Short Answer: Answer the question given below thoroughly and accurately on a separate piece of paper. Make sure to answer ALL parts of the question. Short responses should be approximately 4-6 sentences in length and should take approximately 10 minutes to answer. Dandelions are weeds that are very common in many grassy areas of Texas. Dandelion flowers first open up in a brightyellow stage, and later turn a fluffy white when they are ready to release their seeds. The seeds are carried by the wind and can sometimes travel great distances before landing and growing into new plants. Dandelion stems are usually very long, typically about centimeters (cm). A science teacher discovered an area on her lawn where nearly every dandelion had a stem less than 1 cm long. These short dandelions were growing much more thickly than the taller dandelions in other nearby areas. A) Identify one possible environmental factor that could cause this change in the frequency of different dandelion heights. Explain your answer using the terms natural selection and fitness. B) Justify the following statement: It was advantageous for the original dandelion population to have variation in height.