Exam 1 Practice quiz

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals that are heterozygous for this allele?

0.32

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the frequency of individuals with AA genotype?

0.81

Two species of frogs belonging to the same genus occasionally mate, but the embryos stop developing after a day and then die. These two frog species separate by _____.

reduced hybrid viability

Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus?

Populations tend to increase at a faster rate than their food supply normally allows.

Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?

Simple morphologies convey some advantage in most parasites.

Why should deepwater shrimp on different sides of the isthmus have diverged from each other earlier than shallow-water shrimp?

They have been geographically isolated from each other for a longer time.

An earthquake decimates a ground-squirrel population, killing 98% of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake?

a genetic bottleneck

Given what we know about evolutionary biology, we expect to find the largest number of endemic species in which of the following geological features, which have existed for at least a few million years?

an isolated ocean island in the tropics

Of the following anatomical structures, which is homologous to the bones in the wing of a bird?

bones in the flipper of a whale

Macroevolution is _____.

evolution above the species level

Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. Pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species. These two juniper species are kept separate by _____.

gametic isolation

Darwin and Wallace were the first to propose _____.

natural selection as the mechanism of evolution

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that ____.

island forms are descended from mainland forms

Adult male humans generally have deeper voices than do adult female humans, which is the direct result of higher levels of testosterone causing growth of the larynx. If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females and increasing larynx size in adult males, then _____.

sexual dimorphism was evolving over time in these species

According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that _____.

speciation occurred rapidly in geologic time

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. Which of the following terms best describes this situation?

stabilizing selection

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus, _____.

the allele's frequency should not change from one generation to the next

Catastrophism was Cuvier's attempt to explain the existence of _____.

the fossil record

Use the following description to answer the question(s) below. In the ocean, on either side of the Isthmus of Panama, are thirty species of snapping shrimp; some are shallow-water species, others are adapted to deep water. There are fifteen species on the Pacific side and fifteen different species on the Atlantic side. The Isthmus of Panama started rising about ten million years ago. The oceans were completely separated by the isthmus about three million years ago. In the following figure, the isthmus separates the Pacific Ocean on the left (side A) from the Atlantic Ocean on the right (side B). The seawater on either side of the isthmus is separated into five depth habitats (1-5), with 1 being the shallowest. Which factor is most important for explaining why there are equal numbers of snapping shrimp species on either side of the isthmus?

the relative shortness of time they have been separated