AP Biology AP Classroom Unit 7 FRQ

(b) (i) Using the template, construct an appropriately labeled graph to represent the data in Table 1. (b) (ii) Based on the data, determine whether there is a significant difference in the frequency of EACH allele among the three primate populations.

(b) (i) The sketched bars meet all of the criteria below. Correct axis labeling Correct scale and unit Correctly plotted bar graph The y-axis should be labeled "Frequency." In the best form of the graph, the x-axis is labeled "Alleles," and the frequency bars of a particular allele in each population are adjacent. (b) (ii) The response indicates that based on the lack of overlap among error bars for each allele, there IS a significant difference in the frequency of EACH allele among the three populations.

(c) (i) Based on the data, identify the population that is likely to have the highest frequency of heterozygotes. (c) (ii) Assuming random mating, calculate the frequency of animals in population 1 that carry both alleles 1 and 3.

(c) (i) The response indicates that population 3 is likely to have the highest frequency of heterozygotes (because in population 3 all alleles are present at closest to the same frequencies). (c) (ii) The response indicates that the frequency of animals in population 1 that carry both alleles 1 and 3 is 0.3 or 30%. The calculation is: 2(0.60×0.25)=2×0.15=0.30

(d) (i) A sudden event drastically changes the habitat of each population such that most of the normal vegetation and insects are replaced by other vegetation and insects. One of the scientists claims that population 2 will be the most severely affected. Predict the most likely effect of the event on population 2. (d) (ii) Provide reasoning to justify your prediction.

(d) (i) The response indicates that the number of animals in population 2 will decline. Many of the animals in population 2 are likely to have trouble finding and identifying sources of food. (d) (ii) The response indicates that population 2 has the least genetic diversity of alleles of the opsin gene. The primates in this population will primarily see one wavelength of light/color, that dictated by allele 1, and so may have difficulty distinguishing other new and different forms of food.

Question 2

Researchers studying the phylogenetic relationships among African elephants (Loxodonta africana), Asian elephants (Elephas maximus), and woolly mammoths (Mammuthus primigenius) analyzed cytochrome b DNADNA sequences from several organisms of each species. Cytochrome b is a mitochondrial protein that functions in the electron transport chain. Partial sequences of cytochrome b mitochondrial DNADNA are often used in phylogenetic analyses. DNADNA was obtained from mammoth bone fragments radiocarbon dated to between 12,000 and 14,000 years ago and from living African and Asian elephants. Table 1 shows a partial cytochrome b DNADNA sequence for the reference individual (an African elephant) and some of the sample individuals studied. Dugongs (Dugong dugon) were identified as the outgroup in this study. Dugongs are marine mammals that are relatives of the larger group of elephant-like animals, the proboscideans.

Question 1

Scientists interested in the relationship among vision, foraging for food, and fitness studied three isolated populations of a small species of primate whose diet includes small insects and fruit, both of which the animals primarily identify by sight. The three populations were once part of a larger population that was fragmented as a result of habitat destruction by humans. The study populations were selected on the basis of the significantly different vegetation among their current habitats. The scientists analyzed the frequency in each population of each of three alleles of a gene encoding an opsin protein. Opsin proteins are important for color vision, and each allele provides maximum sensitivity to a specific wavelength of visible light and thus to certain colors. Analysis of the alleles present in each population was performed in two different ways, and the data were combined to calculate the frequencies (Table 1).

(a) Based on the data in Table 1, identify the animal that has the greatest number of sequence differences from the reference animal.

The response indicates that Elephas-2 has 13 sequence differences from the reference animal, and this is the greatest number of all animals in the table.

(d) There are six living species of mammals called hyraxes in the order Hyracoidea. These are small rabbit-like mammals that are also considered to be close relatives of both dugongs and elephants. All of these mammals are widely different morphologically. Explain how organisms that are widely different in morphology can have a close evolutionary relationship.

The response indicates that animals that are related once had a common ancestor with certain genetic characteristics. Adaption to different habitats leads to diversification of morphology but does not change evolutionary relationships.

(a) Describe one measure of evolutionary fitness.

The response indicates that evolutionary fitness is usually measured by reproductive success or that it is measured by the number of offspring produced.

(b) Based on the data in Table 1, complete the cladogram using the template provided to indicate the evolutionary relationships of the four species: African elephants (Loxodonta africana), Asian elephants (Elephas maximus), woolly mammoths (Mammuthus primigenius), and dugongs (Dugong dugon).

The response indicates that from left to right, the order at the tips of the cladogram is: Dugong, Elephas, Loxodonta, Mammathus. Loxodonta and Mammuthus can also be reversed. (Common names can be used; full species names can also be used).

(c) Based on morphological and molecular data, researchers hypothesize that the split between dugongs and proboscideans likely occurred between 48 and 34 million years ago. Explain how molecular data from fossils and living organisms would support the existence of an evolutionary relationship between dugongs and proboscideans.

The response indicates that molecular data, such as that for a widely conserved protein such as cytochrome b, show conserved similarities between organisms such as dugongs and proboscideans and can be used to support the existence of this relationship.