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bio test unit 7 practice

Terms in this set (31)

The role that humans play in artificial selection is to
. choose which organisms breed, and which do not.
Of the following anatomical structures, which is homologous to the bones in the wing of a bird?
. bones in the flipper of a whale
If one wanted to find the largest number of endemic species, one should visit which of the following geological features (assuming each has existed for several millions of years)?
an isolated ocean island in the tropics
Charles Darwin was the first person to propose
. a mechanism for evolution that was supported by evidence
Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of
the fossil record.
DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run?
. None of the individual insects should have possessed genomes that made them resistant to DDT.
if two modern organisms are distantly related in an evolutionary sense, then one should expect that
. they should share fewer homologous structures than two more closely related organisms.
Both ancestral birds and ancestral mammals shared a common ancestor that was terrestrial. Today, penguins (which are birds) and seals (which are mammals) have forelimbs adapted for swimming. What term best describes the relationship of the bones in the forelimbs of penguins and seals, and what term best describes the flippers of penguins and seals?
homologous; analogous
Which of the following must exist in a population before natural selection can act upon that population?
genetic variation among individuals
If Darwin had been aware of genes, and of their typical mode of transmission to subsequent generations, with which statement would he most likely have been in agreement?
a. If natural selection can change one gene's frequency in a population over the course of generations then, given enough time and enough genes, natural selection can cause sufficient genetic change to produce new species from old ones.
In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to ever-colder temperatures, would eventually give rise to ever more cold-tolerant winter wheat. Lysenko's attempts in this regard were most in agreement with the ideas of
d. Lamarck.
DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that
humans and chimpanzees share a relatively recent common ancestor
What was the prevailing belief prior to the time of Lyell and Darwin?
. Earth is a few thousand years old, and populations are unchanging.
Which of the following pieces of evidence most strongly supports the common origin of all life on Earth?
All organisms use essentially the same genetic code.
What must be true of any organ that is described as vestigial?
It must be homologous to some feature in an ancestor.
Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses
Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
In seedcracker finches from Cameroon, small- and large-billed birds specialize in cracking soft and hard seeds, respectively. If long-term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population?
directional selection
Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true?
a. The frequency of the strong-beak alleles increased in each bird as the drought persisted.
Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.
A large population of laboratory animals has been allowed to breed randomly for a number of generations. After several generations, 25% 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 estimated frequency of allele A in the gene pool?
Selected:
a. 0.50
sexual dimorphism is most often a result of
intersexual selection.
Which of the following is most likely to produce an African butterfly species in the wild whose members have one of two strikingly different color patterns?
disruptive selection
Anopheles mosquitoes, which carry the malaria parasite, cannot live above elevations of 5,900 feet. In addition, oxygen availability decreases with higher altitude. Consider a hypothetical human population that is adapted to life on the slopes of Mt. Kilimanjaro in Tanzania, a country in equatorial Africa. Mt. Kilimanjaro's base is about 2,600 feet above sea level and its peak is 19,341 feet above sea level. If the incidence of the sickle-cell allele in the population is plotted against altitude (feet above sea level), which of the following distributions is most likely, assuming little migration of people up or down the mountain?
b.]
In a very large population, a quantitative trait has the following distribution pattern:What is true of the trait whose frequency distribution in a large population appears in the previous figure? It has probably undergone
stabilizing selection
In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple-flowering plants and 64 white-flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population?
c. 0.80
Which of the following is a true statement concerning genetic variation?
. It must be present in a population before natural selection can act upon the population.
In the year 2500, five male space colonists and five female space colonists (all unrelated to each other) settle on an uninhabited Earthlike planet in the Andromeda galaxy. The colonists and their offspring randomly mate for generations. All ten of the original colonists had free earlobes, and two were heterozygous for that trait. The allele for free earlobes is dominant to the allele for attached earlobes.If four of the original colonists died before they produced offspring, the ratios of genotypes could be quite different in the subsequent generations. This would be an example of
genetic drift
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
A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of
a cline.
n the formula for determining a population's genotype frequencies, the 2 in the term 2pq is necessary because
heterozygotes can come about in two ways.
No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is
e. the reshuffling of alleles in sexual reproduction.
The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infant's diet lacks the amino acid phenylalanine. What maintains the presence of this harmful allele in a population's gene pool?
a. heterozygote advantage
diploidy
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