quiz 1

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. These structural similarities are an example of _____.

homology

For a biologist studying a small fish population in the lab, which Hardy-Weinberg condition is easiest to meet?

no gene flow

in the mid-1900s, the soviet geneticist lysenko believed that his winter wheat plants, exposed to increasingly colder temperatures, would eventually give rise to more cold-tolerant winter wheat. lysenko's attempts in this regard were most in agreement with the ideas of _____.

Lamarck

Which of these conditions are always true of populations evolving due to natural selection? Condition 1: The population must vary in traits that are heritable. Condition 2: Some heritable traits must increase reproductive success. Condition 3: Individuals pass on most traits that they acquire during their lifetime.

Conditions 1 and 2

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

The role that humans play in artificial selection is to _____.

choose which organisms reproduce

Currently the only predators of Galápagos marine iguanas are Galápagos hawks. Iguana body size is not correlated with risk of hawk predation, although small iguanas can sprint faster than large iguanas. If predators (for example, cats) that preferably catch and eat slower iguanas are introduced to the island, iguana body size is likely to _____ in the absence of other factors; the iguanas would then be under directional selection.

decrease

which of the following is the most predictable outcome of increased gene flow between two populations?

decreased genetic difference between the two populations

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it _____.

dismissed the idea that species are constant and emphasized the importance of variation and change in populations

After the drought of 1977, researchers hypothesized that on the Galápagos island Daphne Major, medium ground finches with large, deep beaks survived better than those with smaller beaks because they could more easily crack and eat the tough Tribulus cistoides fruits. A tourist company sets up reliable feeding stations with a variety of bird seeds (different types and sizes) so that tourists can get a better look at the finches. Which of these events is now most likely to occur to finch beaks on this island?

evolution of yet larger, deeper beaks over time

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s. They do not marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations including those in their original homeland. Which of the following likely explains the genetic uniqueness of this population?

genetic drift

which of the following must exist in population before natural selection can act upon that population?

genetic variation among individuals

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