Evolution PCB4674 Midterm exam2 Mar

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1 Evolution PCB4674 Midterm exam2 Mar Name: ID: For each multiple choice question select the single est answer. Answer questions 1 to 20 on your scantron sheet. Answer the remaining questions in the space provided or on the figures. Brevity is rewarded. Please print clearly. Each multiple choice question is worth 1 point. For short answer questions, the numer of points is indicated in parentheses at the end of each question. 1 A point mutation is: a) a single allele sustitution in DNA ) a single ase sustitution in DNA c) a single chromosome sustitution in DNA d) a single gene sustitution in DNA 2 What is the Red Queen hypothesis? a) sexual selection is driven y female choice ) organisms have to evolve as fast as they can just to keep pace with evolution of other organisms around them c) genetic diversity is maintained y natural selection d) allele frequencies will not change generation after generation 3 An insertion or deletion of a ase changes the codon reading sequence. This is knows as: a) frameshift mutation ) point mutation c) chromosome inversion d) transversion a 4 Given a low degree of heritaility for a trait and a low selection differential, what would e the predicted evolutionary response to selection? R=h 2 S a) high ) low c) intermediate d) any of the aove e) insufficient information to answer that question 5 The vast majority of mutations are: a) strongly eneficial

2 c ) neutral to slightly eneficial c) neutral to slightly deleterious d) strongly deleterious e) lethal 6 Genetic drift is most important in: a) large populations ) small populations c) asexual populations d) sexually reproducing populations e) all of the aove 7 Random genetic drift will cause the average heterozygosity in a population to: a) increase ) decrease c) remain stale d) all of the aove are possile 8 If 2 groups compete for the same ecological niche, one will drive the other to extinction. This is known as: a) character displacement ) community interaction c) competitive exclusion d) resource partitioning c 9 Evolution aove the species level is known as: a) microevolution ) gradualism c) population genetics d) saltation e 10 The rapid diversification of a small group of ancestral species into a large numer of descendant species that occupy a wide range of ecological niches is known as: a) adaptive radiation ) gradualism c) migration d) drift e) sexual selection

3 a 11 Evolutionary changes that fluctuate around a mean value and give the overall appearance of stasis are known as: a) punctuated equilirium ) gradualism c) selection d) mutation e) zigzag evolution e 12 What is a polymorphism? a) a difference in the rate of evolutionary change ) expression of different protein products from the same allele c) multiple mutations in a single individual d) more than 1 possile allele at a particular locus d 13 What effect does inreeding have on the frequency of homozygotes in a population? a) increases homozygotes ) decreases homozygotes c) stailizes frequency of homozygotes d) all of the aove are possile a 14 In the realm of population genetics, evolution is defined as: a) any violation of Hardy-Weinerg Equilirium assumptions ) the appearance of a new species c) a change in allele frequencies across generations d) all of the aove e) population genetics has nothing to do with evolution c 15 Which of the following are mechanisms of divergence that can lead to speciation? a) genetic drift ) sexual selection c) natural selection d) all of the aove d 16 Define resource partitioning. (1)

4 Species minimize harmful effects of direct competition y using different aspects of their common environment 17 List 2 assumptions required for Hardy-Weinerg Equilirium. The requisite assumptions for HWE are unrealistic and unlikely to e found in any population so what is the value of this model? (3) No selection, no mutation, no migration, no drift, no assortative mating Allows us to quantify what will happen when each assumption is violated 18 Briefly descrie Eldredge and Gould s concept of punctuated equilirium. What derogatory term was applied to their concept? (3) Evolution tends to e characterized y long periods of stasis punctuated y episodes of very fast development of new forms Evolution y jerks 19 Hardy-Weinerg equilirium states that regardless of allele frequencies, genotype frequencies will go to and remain at: (1) p 2 + 2pq + q 2 = 1 20 Distinguish etween allopatric and sympatric speciation. Give an example (real or hypothetical) of allopatric speciation. (3) allopatric speciation populations evolve in geographic isolation sympatric speciation populations evolve in geographic proximity 21 Distinguish etween Batesian and Muellerian mimicry. (3) Batesian 1 species mimics another Muellerian 2 species share similar aposematic coloration 22 Distinguish etween coevolution and cospeciation. (3) coevolution evolutionary changes in 1+ species in response to changes in other species in the same community cospeciation speciation process that occurs in 2 interacting species simultaneously

23 Lael these selection modes. (3) directional disruptive stailizing 24 Lael these two hypotheses for the evolution of different morphologies over time.

3cm and mean midparent value for the one third of the population with the longest tails =19.9cm.

7 and the mean midoffspring value for the offspring of the parents with the longest tails =20.1, what is the heritaility of the selected trait?

875 selection differential (R) = 0.7 26 You oserve a field of wildflowers with the following genotype frequencies: AA: 144, Aa: 100, aa: 81.

5 23 Lael these selection modes. (3) directional disruptive stailizing 24 Lael these two hypotheses for the evolution of different morphologies over time. (2) saltation gradualism 25 For a population of mice, the mean midparent value for tail length for the entire population =18.3cm and mean midparent value for the one third of the population with the longest tails =19.9cm. If the mean midoffspring value for the entire population =18.7 and the mean midoffspring value for the offspring of the parents with the longest tails =20.1, what is the heritaility of the selected trait? Given a selection differential of 0.8, what is the predicted evolutionary response (R)? (3) O* -O P * -P = R S heritaility (h 2 ) = selection differential (R) = You oserve a field of wildflowers with the following genotype frequencies: AA: 144, Aa: 100, aa: 81. i) What are the allele frequencies? ii) What are the expected genotype frequencies under Hardy-Weinerg equilirium assumptions? iii) Is this population in Hardy- Weinerg equilirium (ie. is the oserved genotype frequency close to the expected frequency)? (6) i) A: ; a: ii) AA: ; Aa: ; aa: iii) no, oserved numers are very different from expected

6 27 Given initial allele frequencies of A: 0.9 and a: 0.1, calculate the i) genotype frequencies for a population of 1000 individuals ii) genotype frequencies after selection eliminates 40% of all homozygotes and ii) final allele frequencies. Which conclusion(s) is violated. (6) i) AA: 810; Aa: 180: aa: 10 ii) AA: 486; Aa: 180; aa: 6 iii) A: ; a: selection violates conclusion 1: allele frequencies in a population will not change, generation after generation

7 28 Choose any one of the required chapters from The Origin of Species (Difficulties on theory, Instinct, Hyridism, Geological record, Geological succession) and provide a rief summary of the chapter including at least 2 examples mentioned y Darwin. (8)

The theory of evolution continues to be refined as scientists learn new information.

Section 3: The theory of evolution continues to be refined as scientists learn new information. K What I Know W What I Want to Find Out L What I Learned Essential Questions What are the conditions of the