Ap Biology Chapter 18 Quiz

Natural selection is not based on what?

individuals adapting to their environments and, thereby, evolving

You sample a population of butterflies and find that 42% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?

.49

In a Hardy-Weinburg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.4. What is the percentage of the population that is homozygous for this allele?

32

If, on average, 46% of the loci in a species' gene pool are heterozygous, then the average homozygosity of the species should be...

46%

What situations would most likely lead to allopatric speciation...

A flood causes the formation of a new lake

Which naturalist synthesized a concept of natural selection independently of Darwin?

Alfred Wallace

Males of one species sing only when its predators are absent; males of another species sing only when its predators are present. What kind of reproductive barrier is this?

Behavioral

Structures as different as human arms, bat wings, and dolphin flippers contain man of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities?

By identifying the bones as being homologous and proposing that humans, bats, and dolphins share a common ancestor.

When closely related individuals mate with each other, or inbreed, the offspring are often not as fit as the offspring of two unrelated individuals. Why?

Close relatives are genetically incompatible

Darwin's mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of earth's ancient age?

Charles Lyell

What must exist in a population before natural selection can act upon that population.

Genetic variation among individuals

One species lives only in tree holes; another species lives only in streams. What kind of reproductive barrier is this?

Habitat

What is a true statement concerning genetic variation?

It arises in response to changes in the environment

What consistently requires a small population as a precondition for its occurence?

Natural Selection

What evolutionary agents is most consistent at causing population to become better suited to their environments over the course of generations?

Non-random mating

What is the main difference between dispersal and vicariance?

One involves the movement of the organisms, and the other involves a change in the enviroment

What describes the continued divergence of species based on the low fitness of hybrid offspring?

Reinforcement

One species mates at the season when daylight is increasing from 13 hours to 13 hours, 15 minutes; another species mates at the season when daylight is increasing from 14 hours to 14 hours, 15 minutes. What kind of reproductive barrier is this?

Temporal

What is the main difference between autopolyploid and allopolyploid?

The source of the extra chromosomes

What situation is not an example of a prezygotic barrier?

Two species of insects produce infertile offspring

A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of...

a bottleneck

What is the smallest unit that natural selection can change?

a species gene frequency

A hybrid zone is properly defined as...

an area where mating occurs between members of two closely related species, producing viable offspring.

The theory of evolution is most accurately described as...

an overarching explanation, supported by much evidence, for how populations change over time.

Fossil evidence indicates that horses have gradually increased in size over geologic time. What term best describes this?

directional selection

A certain species of land snails exists as either a cream color or a solid brown color. Intermediate individuals are relatively rare. What term describes this?

diversifying selection

Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fin and tails, as do fish, even through their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are...

examples of convergent evolution and adaptions to a common environment

Gene flow is a concept best used to describe an exchange between...

individuals

According to the punctuated equilibria model...

most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species.

When males and females of a population look or act differently, it is referred to as...

sexual dimorphism

Theoretically, the production of sterile mules be interbreeding between female horses and male donkeys should...

strengthen postzygotic barriers between horses and donkeys