Q: Given allele frequencies $$p = 0.55$$ for allele A and $$q = 0.45$$ for allele B in a population of 300, how many heterozygotes ($$AB) $$would you expect under Hardy-Weinberg equilibrium?

$$2pq \times 300 = 0.495 \times 300 = 148.5$$

Q: Researchers observe 560 $$TT$$, 280 $$Tt$$, and 160 $$tt$$ plants in a population of 1000. What is the frequency of the $$T$$ allele?

$$f(T) = \frac{2 \times 560 + 280}{2 \times 1000} = \frac{1400}{2000} = 0.7$$

Question 1

Chick, human, and cat embryos have similar gill pouches. What type of evidence for evolution is this?

Accepted Answer

Embryological evidence

Question 2

Both cats and dogs have tails, as did their most recent common ancestor. What type of evidence for evolution is this?

Accepted Answer

Homologous structures

Question 3

Which of the following must be true for a trait to be under natural selection in cotton-topped tamarins?

Accepted Answer

The trait must be heritable and affect reproductive success.

Question 4

A lab partner suggests that carnivorous fish evolved teeth in order to eat clams. Why is this thinking incorrect?

Accepted Answer

Traits arise by random mutation and are selected for if advantageous.

Question 5

Given allele frequencies $$p = 0.55$$ for allele A and $$q = 0.45$$ for allele B in a population of 300, how many heterozygotes ($$AB) $$would you expect under Hardy-Weinberg equilibrium?

Accepted Answer

$$2pq 	imes 300 = 0.495 	imes 300 = 148.5$$

Question 6

Researchers observe 560 $$TT$$, 280 $$Tt$$, and 160 $$tt$$ plants in a population of 1000. What is the frequency of the $$T$$ allele?

Accepted Answer

$$f(T) = \frac{2 	imes 560 + 280}{2 	imes 1000} = \frac{1400}{2000} = 0.7$$

Question 7

Given the observed genotype frequencies in the previous question, is the population evolving?

Accepted Answer

Yes, because the observed and expected genotype frequencies differ.

Question 8

Two populations of birds with different coloration live on opposite sides of a peninsula and do not interbreed due to unsuitable habitat between them. What keeps the two populations separate?

Accepted Answer

Geographical (habitat) isolation

Question 9

Rocky Mountain juniper and one-seeded juniper are kept separate by pollen grains from one species being unable to fertilize the ovules of the other. What type of reproductive isolation is this?

Accepted Answer

Gametic isolation

Question 10

In hybrid zones where reinforcement is occurring, what would you expect to observe with respect to gene flow?

Accepted Answer

Decreased gene flow between populations

Question 11

According to the phylogenetic tree, what is the closest related group to iguanian lizards?

Accepted Answer

Geckos

Question 12

Are turtles and birds more closely related than birds and crocodiles, according to the tree?

Accepted Answer

No, birds and crocodiles share a more recent common ancestor.

Question 13

Where on a phylogenetic tree would you find the most recent common ancestor between non-avian dinosaurs and crocodiles?

Accepted Answer

At the node where the branches for non-avian dinosaurs and crocodiles meet.

Question 14

In both fruit flies and humans, the protein Acat1 converts cholesterol into a storage form. If 65% of the amino acids are identical, is this an example of homology or convergent evolution?

Accepted Answer

Homology, because the similarity is due to shared ancestry.

Question 15

Which of the following is NOT a requirement for Hardy-Weinberg equilibrium?

Accepted Answer

Small population size

Question 16

If a population is not in Hardy-Weinberg equilibrium, what can you infer?

Accepted Answer

The population is evolving.

Evolutionary Evidence, Population Genetics, and Speciation: Study Notes

Study Guide - Practice Questions

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