Mastering Bio Unit 7

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?

.32

In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.3. What is the frequency of individuals that are homozygous for this allele?

0.09

On the Bahamian island of Andros, mosquitofish populations live in various, now-isolated, freshwater ponds that were once united. Currently, some predator-rich ponds have mosquitofish that can swim in short, fast bursts; other predator-poor ponds have mosquitofish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquitofish exhibit exclusive breeding preferences.Which two of the following have operated to increase divergence between mosquitofish populations on Andros?1. improved gene flow2. bottleneck effect3. sexual selection4. founder effect5. natural selection

3 and 5

Arrange the following in order from most general to most specific.1 natural selection2. microevolution3. intrasexual selection4. evolution5. sexual selection

4, 2, 1, 5, 3

Which statement about variation is true?

All new alleles are the result of nucleotide variability.

You sample a population of butterflies and find that 56% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population?

Allele frequency cannot be determined from this information.

During a study session about evolution, one of your fellow students remarks, "The giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result." Which statement is most likely to be helpful in correcting this student's misconception?

Characteristics acquired during an organism's life are generally not passed on through genes.

Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true?

Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?

India was a separate continent until forty-five million years ago.

What is true of the fossil record of mammalian origins?

It includes transitional forms with progressively specialized teeth.

What must be true of any organ described as vestigial?

It must be homologous to some feature in an ancestor.

Which eukaryotic kingdom includes members that are the result of endosymbioses that included an ancient aerobic bacterium and an ancient cyanobacterium?

Plantae

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.

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees?

Similarity due to common ancestry should be more common than similarity due to convergent evolution.

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

Simple morphologies convey some advantage in most parasites.

A biologist studied a population of squirrels for fifteen years. During that time, the population was never fewer than thirty squirrels and never more than forty-five. Her data showed that over half of the squirrels born did not survive to reproduce, because of both competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to eighty. Which inference(s) about this most recent surge in the population size might be true?

The amount of available food may have increased and/or the predators that prey upon squirrels may have decreased.

Two researchers experimentally formed tetraploid frogs by fertilizing diploid eggs from Rana porosa brevipoda with diploid sperm from Rana nigromaculata. When they mated these tetraploid frogs with each other, most of the offspring that survived to maturity were tetraploid, with chromosome sets of both diploid parent species. Based on these results, if this type of tetraploid formed in the wild, what would be the result? (Y. Kondo and A. Kashiwagi. 2004. Experimentally induced autotetraploidy and allotetraploidy in two Japanese pond frogs. Journal of Herpetology 38(3):381-92.)

The tetraploids would be reproductively isolated from both parent species.

Which of the following is a fitness trade-off (compromise)?

Turtle shells provide protection but are heavy and burdensome when moving.

Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came in contact?

a behavioral reproductive isolating mechanism

The most important feature that permits a gene to act as a molecular clock is _____.

a reliable average rate of mutation

In a comparison of birds and mammals, having four limbs is _____.

a shared ancestral character

Upon being formed, oceanic islands, such as the Hawaiian Islands, should feature what characteristic, leading to which phenomenon?

a variety of empty ecological niches, leading to adaptive radiation

A population of organisms will not evolve if _____.

all individual variation is due only to environmental factors

Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?

biological

Speciation _____.

can involve changes to a single gene

An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to _____.

cause iron in ocean water and terrestrial rocks to rust (oxidize)

To apply parsimony to constructing a phylogenetic tree, _____.

choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology

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

choose which organisms reproduce

You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is to _____.

cross your flies with flies from another lab

Which of the following is the best modern definition of evolution?

descent with modification

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

Macroevolution is _____.

evolution above the species level

The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. The outcome of the conflict between bacteria and bacteriophage at any point in time results from _____.

frequency-dependent selection

Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing _____.

gene flow

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

genetic variation among individuals

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?

habitat isolation

How were conditions on the early Earth of more than three billion years ago different from those on today's Earth? Unlike Earth today, early Earth _____.

had an atmosphere rich in gases released from volcanic eruptions

The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that _____.

having an extra copy of a gene permits modifications to the copy without loss of the original gene product

In the formula for determining a populations genotype frequencies, the "pq" in the term 2pq is necessary because _____.

heterozygotes have two alleles

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as _____.

homoplasies

The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma. These species have apparently undergone speciation from ancestral stock since the last glacial retreat about ten thousand years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species?

mitochondrial DNA

The importance of computers and of computer software to modern cladistics is most closely linked to advances in _____.

molecular genetics

Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in _____.

mutations to homologous genes

Certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This evidence supports the claim that _____.

natural selection can produce new structures by coupling together parts of other structures

A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. The actual forelimbs of these mammals do not seem to be optimally arranged because _____.

natural selection is generally limited to modifying structures that were present in previous generations and in previous species

The duplication of homeotic (Hox) genes has been significant in the evolution of animals because it _____.

permitted the evolution of novel forms

The production of sterile mules by interbreeding between female horses (mares) and male donkeys (jacks) is an example of _____.

reduced hybrid fertility

The best classification system is that which most closely _____.

reflects evolutionary history

In a hypothetical environment, fishes called pike-cichlids are visual predators of large, adult algae-eating fish (in other words, they locate their prey by sight). The population of algae-eaters experiences predatory pressure from pike-cichlids. Which of the following is least likely to occur in the algae-eater population in future generations?

selection for larger female algae-eaters, bearing broods composed of more, and larger, young

The legless condition that is observed in several groups of extant reptiles is the result of _____.

several instances of the legless condition arising independently of each other

What statement represents the explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? Dogs and wolves _____.

share a very recent common ancestor

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of _____.

sympatric speciation and habitat isolation

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

Soon after the island of Hawaii rose above the sea surface (somewhat less than one million years ago), the evolution of life on this new island should have been most strongly influenced by _____.

the founder effect

The various taxonomic levels (for example, phyla, genera, classes) of the hierarchical classification system differ from each other on the basis of _____.

their inclusiveness

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily?

to serve as an outgroup

Which of the following evidence most strongly supports the common origin of all life on Earth? All organisms _____.

use essentially the same genetic code