Midterm1Key

Midterm1Key - Your name EEB 122b FIRST MIDTERM Page 1 Your name 1 Question 1 B B could have any slope(pos or neg but must be above A for all values

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Your name: _____________________ Page 1 EEB 122b FIRST MIDTERM
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Your name: _____________________ Page 2 1 Question 1 The axes above relate individual growth rate to temperature for Daphnia (a water flea that can reproduce asexually). On this UPPER set of axe (a) draw and label a reaction norm for genotype A, which does not have a plastic response to temperature (3 pts), AND (b) draw and label a reaction norm for genotype B, which has a plastic response to temperature and a higher growth rate than A at all temperatures (3 pts). (c) On this LOWER set of axes, draw and label reaction norms for genotypes C and D. Genotype C has a higher individual growth rate than genotype D at 10ºC, but genotype D has a higher individual growth rate at 15ºC (4 pts). (d) What must be true of individual growth rate if genotype C outcompetes genotype D over many generations at 10ºC, replacing it completely at that temperature? (2 pts) A higher individual growth rate at 10ºC must lead to higher fitness. A B B could have any slope (pos or neg) but must be above A for all values shown C D Again, many acceptable variations exist
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Your name: _____________________ Page 3 Question 2 A new allele A occurs in a large diploid population and eventually increases in frequency to fixation. a. (6 pts) Draw and label the allele frequency of A from near zero at time zero (black dot at the lower left) to fixation through time (in generations) if A is… I. Dominant and has a selective advantage over other alleles II. Recessive and has a selective advantage over other alleles III. Is neutral to other alleles (and does go to fixation) Allele A has now reached fixation. A mutation then occurs that results in a single copy of allele B at the same locus. b. If the population consists of 100 individuals, what is the frequency of B ? (3 pts) The frequency of a single mutant allele in a population of N diploid individuals = 1/2N F = 1 2 N = 1 2*100 = 1 200 = 0.005 c. If B is neutral to A , what is the probability that B increases to fixation? (3 pts) Probability of fixation = frequency for neutral alleles P = F = 1 200 = 0.005
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Your name: _____________________ Page 4 Question 3 (a) Define homology (2pts): Similarity in a trait among two or more species, suggesting descent from a common ancestor. (b) Define homoplasy (2pts): Similarity in a trait for reasons other than descent from a common ancestor, such as convergence. (c) For the tree above, does the circle represent a monophyletic, paraphyletic, or polyphyletic group? (2pts) Paraphyletic group because it doesn’t contain all the descendants of the most recent common ancestor. (d) For the tree above, assume the ancestor had scales, long femurs, and a small vocal sac. Which species have smooth skin, long femurs, and a large vocal sac? (4pts)
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This note was uploaded on 02/07/2012 for the course EEB 122 taught by Professor Stephenstearns during the Spring '09 term at Yale.

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Midterm1Key - Your name EEB 122b FIRST MIDTERM Page 1 Your name 1 Question 1 B B could have any slope(pos or neg but must be above A for all values

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