Evolutionary Biology Exam 2 Review

After controlling for the effect of relatedness among species of bats,
 what was the conclusion with regard to testes size in bats?

testes size is related to social group size

larger bats had larger testes size

larger bats had smaller testes

testes size is not really related to body size

Testes size is related to social group size

If there are 29 B1B1 individuals, 38 B1B2 individuals, 
and 72 B2B2 individuals, then what is the frequency of B1B1?

17.4%

20.8%

15%

72%

20.8%

In humans, sexual selection is likely to be greater in 
men than in women because

Females spend more time and energy producing 
offspring than males

Female choice favors tall men.

Males invest more resources per gamete than females.

Females spend more time and energy producing offspring than males

Most of the 20 amino acids are encoded by more than one codon. 
We might expect that codon usage would be random, and that each 
codon in a suite of synonymous codons would be present in equal 
numbers. However, this is not true. What name is given to the above
 phenomenon? 

Codon bias 

Hitchhiking 

Background selection 

Positive selection

Codon bias

What is sexual dimorphism?

an asymmetric sex ratio at birth

a difference in male reproductive rates.

a difference in males and females of a species.

a population with a mix of sexual and asexual 
individuals

A difference in males and females of a species

Using the comparative method can reduce? 

bias 

bias due to study design 

variation

bias due to evolutionary relationships 

Bias due to evolutionary relationships

Male pipefish selecting less parasite-ridden females to mate with is 
an example of which type of sexual selection?

intrasexual selection

intersexual selection

Intersexual selection

Phenotypic plasticity describes a scenario where individuals with 
identical genotypes may have different phenotypes if they live in 
different environments.

False

True

True

Sexual selection by mate choice leads to

Evolution of elaborate courtship displays

Choosy females

Males mating with less than normal number of females

Higher parental investment

Evolution of elaborate courtship displays

Why don't Fuchsia flowers drop immediately after pollination has 
finished?

 the color change allows more photosynthesis

they wait until the pollen tube has reached the ovary

they want to trick the pollinators into visiting more

they cannot because they are physically unable

They wait until the pollen tube has reached the ovary

In an unstable equilibrium, the frequency of favored allele A is 0.5.
 If this frequency rises above 0.5, the frequency will do what?

Stay the same

Decrease quickly to 0.0

Rise quickly to 1.0

There is not enough information to determine 
what would happen

Rise quickly to 1.0

What is the similarity between frequency-dependent selection and 
heterozygote superiority?

Both patterns of selection decrease genetic diversity among individuals.

Both patterns of selection lead to homozygotes 
having a much higher fitness that the other.

Both patterns of selection lead to an increase in mutations.

Both patterns of selection maintain genetic diversity in populations.

Both patterns of selection maintain genetic diversity in populations

Assuming Hardy-Weinberg Equilibrium, in a population of 
100 individuals, if phenotype frequencies are equal to AA and Aa 75% 
and aa 25%, what is the probability of obtaining a homozygote 
recessive zygote?

25%

12.5%

75%

62.5%

25%

Why do male lions commit infanticide?

So that their cubs will have less future competition to acquire mates

So the mothers of those cubs will mate with them

Male lions will eat any fresh meat they can capture

Lions are spiteful

So the mothers of those cubs will mate with them

What is the effective population size if you have 50 males and 100 
females in a population? Assume random mating, no selection, 
mutation, or migration, and round to the nearest whole number.

122

133

111

144

133

Assume Hardy-Weinberg equilibrium. In a population with 756 
individuals, if genotype frequencies are equal to AA 36%, Aa 48%, 
and aa 16%, what is the probability of obtaining an "Aa” zygote? 

48% 

60% 

16%

36% 

48%

Australia has a population of koalas with 1,000 individuals. 
Each generation, the migration rate of koalas floating out to Fiji 
Island is m = 0.01. At koala locus K, there are K and k alleles, 
and the k frequency on Australia is 0.9 whereas it is 0.4 on Fiji 
island in generation 0. What will the k allele frequency be on the 
island in generation 1, after migration from the mainland? You can 
ignore genetic drift.

0.405

0.005

0.905

0.45

0.405

In the one-island model, which quantity can you ignore?

The allele frequencies on the island

The allele frequencies on the mainland

The proportion of island emigrants

The proportion of island immigrants

The proportion of island emigrants

Among the nonselective mechanisms of evolution, 
there is one that is absolutely random, which is it? 

Mutation 

Migration 

Genetic drift 

Inbreeding 

Genetic drift

The frequency of a recessive loss-of-function allele ‘e’ in a
 population of pig frogs is 0.02. Individuals with genotype ee do 
not develop functional eyes, and are easy targets for predators, 
thus the fitness of ee individuals is 0.1 compared to fitness of 
1 for Ee and EE frogs. What must the mutation rate of E to e be for 
the frequency of e to be maintained in the population at 0.02 
frequency by mutation-selection balance?

m = 0.036

m = 0.00036

m = 0.018

m = 0.000018

m = 0.00036

Assume Hardy-Weinberg equilibrium. In a population with 375 
individuals, if genotype frequencies are equal to AA 36%, Aa 48%, 
and aa 16%, what is the probability of obtaining a sperm with an “a”? 

40% 

31% 

60%

16% 

40%

Small male iguanas deal with interrupting copulation by

Producing spermatophores for females to pick up from 
the environment

Ejaculating faster

Ejaculating while copulation occurs

Ejaculating prior to copulation so sperm is ready to 
be deposited immediately

Ejaculating prior to copulation so sperm is ready to be deposited immediately

In which of the following scenarios would it be important to 
perform phylogenetically independent contrasts?

 To test for a correlation between genome size and 
host specificity among an array of parasitic species

To test for a correlation between diet and toxicity 
across populations within a species

To infer whether variation in beak size is heritable 
in a single population

To test for correlation between genome size and host specificity among an array of parasitic species

What was Bateman's key insight that furthered the study of sexual selection?

That reproductive success in males is dependent upon 
the variation in sexually selected traits possessed 
by that male

That sometimes natural selection and sexual selection 
are opposing forces

That to understand sexual dimorphism we must quantify
the relationship between number of mates and 
reproductive success for both males and females

That some species are sex-role reversed

That to understand sexual dimorphism we must quantify the relationship between number of mates and reproductive success for both males and females

Under a system where the heterozygote allele is favored 
(overdominance) we would expect to see what happen to a lethal 
homozygote genotype? 

It should be maintained in the population indefinitely 

The homozygotes actually increase in frequency in a 
slow but continuous manner. 

The homozygotes will slowly disappear until all lethal
 alleles are only present in heterozygotes. 

Homozygotes evolve wings and fly away 

It should be maintained in the population indefinitely