Evolution

A population of rabbits may be brown (the dominant phenotype) or white (the recessive phenotype). Brown rabbits have the genotype BB or Bb. White rabbits have the genotype bb. The frequency of the BB genotype is 0.64. What is the frequency of the b allele?

0.2

What is the estimated frequency of allele a in the gene pool in question 18?

0.60

Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Differential reproduction occurs. 2. A new selective pressure arises. 3. Allele frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship.

2, 4, 1, 3

You are studying a population of horned lizards. The population is in Hardy-Weinberg equilibrium. The skin is variable, with either purple or green lizards. The gene for skin color has two alleles, G and g. You determine that the allele frequency in the population is: G=0.8, g=0.2. If you examined 100 lizards, which of the following genotypic ratios would you expect?

64GG, 32Gg, 4gg

If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology?

D and F

Directional selection differs from stabilizing selection in that:

Directional selection favors one end of the phenotype distribution, whereas stabilizing selection favors intermediate over extreme phenotypes.

Diploidy may help to preserve genetic variation because __

Dominant alleles hide recessive alleles from selection in heterozygotes

Which of the following is the correct sequence of events for the origin of life? I. formation of protobionts II. synthesis of organic micromolecules III. synthesis of organic polymers IV. formation of DNA-based genetic systems

II, III, I, IV

According to the Red Queen Hypothesis, if a parasite evolved to become more lethal to its host, one might expect:

The host to evolve better defenses against the parasite to increase survivorship

Which factor likely did not contribute to the genetic diversification of the Galápagos Island finches studied by Darwin? A) Environmental conditions vary among the different islands. B) Most of the islands are sufficiently distant from one another such that movement among their populations is limited. C) The islands are only 100 km from Ecuador, so they receive a continual input of new genes from the mainland. D) Occasional migrants to new islands rarely interbreed with endemic species. E) Over time, the residents of each island have developed their own genetic distinctiveness.

The islands are only 100 km from Ecuador, so they receive a continual input of new genes from the mainland.

A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 36% of the animals display a recessive trait (aa), the same percentage as at the beginning of the breeding program. The rest of the animals show the dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants. What is the most reasonable conclusion that can be drawn from the fact that the frequency of therecessive trait (aa) has not changed over time?

The two phenotypes are about equally adaptive under laboratory conditions.

Which of the following tree(s) below are consistent with the data in the character table above?

Tree 2

Which statement about natural selection is most correct?

Well-adapted individuals leave more offspring, and thus contribute more to the gene pool, than poorly-adapted individuals.

The evolution of multiple species that occupy many different environments, from a single ancestral form, is best described as an example of:

adaptive radiation.

Which measurement would help determine absolute dates by radiometric means? A) the accumulation of the daughter isotope B) the loss of the parent isotope C) the loss of daughter isotope D) answers A-C all apply E) answers A and B only

answers A and B only

Evidence for the endosymbiotic theory includes the observation that mitochondria A) have their own DNA B) reproduce independently C) both of these (A and B) D) neither of these

both of these (A and B)

Alfred Wallace

came up with a theory of natural selection very similar to Darwin's theory.

Heterochrony refers to:

changes in the timing or sequence of developmental events

The fact that many forms of aquatic animals look alike, even though they have diverse, and distantly related ancestors, could be attributed to:

convergent evolution

Fossil evidence indicates that horses(both sexes) have gradually increased in size over geologic time. This is evidence of:

directional selection

Imagine if through time, the movement of iguanas among different islands of the Galapagos island chain decreased due to boat traffic around the islands. This may alter the course of evolution in iguanas by decreasing:

gene flow

A defining characteristic of allopatric speciation is:

geographic isolation.

In a large, sexually reproducing population , the frequency of an allele changes from 0.7 to 0.2 without a change in population size. From this change, one can most logically assume that, in this environment:

he allele reduces evolutionary fitness.

Kimura's neutral theory of molecular (DNA) evolution would predict:

higher rates of synonymous substitutions than non-synonymous substitutions.

Gene flow between two populations will ____________ genetic variation within one population through time, and _________ the differences between the two populations through time.

increase/decrease

What type of selection is most likely responsible for the large antlers seen on male elk?

intrasexual selection

Different species of damselflies (a type of insect) can be distinguished by a variety of traits including the morphology of the male copulatory organ. Because of these anatomical differences, males of one species of damselfly are unable to mate with females of other species of damselflies. This limitation is an example of ___________, which is a form of ___________.

mechanical isolation; prezygotic barrier

The heritable source of all genetic variation is:

mutation

Self-fertilization is common in many plant species but less common in animals. One consequence of this difference is that

new species can arise in plants through polyploidy much more easily than they can in animals.

Vestigial traits are good examples of:

nonadaptive traits.

If you were using the principle of parsimony to reconstruct evolutionary histories, you would:

select the tree that contains the fewest shared, derived characters

Male satin bowerbirds adorn structures that they build, called "bowers," with parrot feathers, flowers, and other bizarre ornaments in order to attract females. Females inspect the bowers and, if suitably impressed, allow males to mate with them, after which they go off to nest by themselves. The evolution of this behavior is best described as due to:

sexual selection.

All of the following are criteria for maintaining Hardy-Weinberg equilibrium involving two alleles except: A) the frequency of all genotypes must be equal. B) there must be no natural selection. C) matings must be random. D) there must be no mutation E) gene flow from other populations must be zero.

the frequency of all genotypes must be equal.

Each of the following phrases describes the process of evolution EXCEPT A) changes in allele frequency over time B) traits acquired by an individual during its lifetime are passed on to its offspring C) descent with modification D) progressively more complex forms of life are derived from simpler ancestors

traits acquired by an individual during its lifetime are passed on to its offspring

The modern human species (Homo sapiens) evolved approximately how long ago?

two hundred thousand years ago

Oxygen in the atmosphere

was produced by biological processes after the evolution of life