Bio 2 final

Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship.

2 → 4 → 1 → 3

Rank the following one-base point mutations (from most likely to least likely) with respect to their likelihood of affecting the structure of the corresponding polypeptide. 1. insertion mutation deep within an intron 2. substitution mutation at the third position of an exonic codon 3. substitution mutation at the second position of an exonic codon 4. deletion mutation within the first exon of the gene

4, 3, 2, 1

How many separate species, both extant and extinct, are depicted in this tree?

6

According to this tree, what percent of the species seem to be extant (i.e., not extinct)?

66%

Which of these conditions should completely prevent the occurrence of natural selection in a population over time?

All variation between individuals is due only to environmental factors.

Within a few weeks of treatment with the drug 3TC, a patientʹs HIV population consists entirely of 3TC-resistant viruses. How can this result best be explained?

A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency.

Which of these naturalists synthesized a concept of natural selection independently of Darwin?

Alfred Wallace

Which statement about variation is true?

All new alleles are the result of nucleotide variability

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

Which group is composed entirely of individuals who maintained that species are fixed (i.e., unchanging)?

Aristotle, Linnaeus, and Cuvier

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

Genetic variation among individuals

Monkeys of South and Central America have prehensile tails, meaning that their tails can be used to grasp objects. The tails of African and Asian monkeys are not prehensile. Which discipline is most likely to provide an evolutionary explanation for how this difference in tails came about?

Biogeography

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. How do biologists interpret these similarities?

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

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

Characteristics acquired during an organismʹs life are generally not passed on through genes.

Darwinʹs mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earthʹs ancient age

Charles Lyell

Who would have proposed that the boundaries between each stratum mark the occurrence of different localized floods?

Cuvier

Refer to the accompanying figure. Which one of the following is NOT a plausible hypothesis to explain the differences in caterpillar appearance observed in this population?

Differences in air pressure, due to differences in elevation, trigger the development of different types of caterpillars

Refer to the accompanying figure. In every case, caterpillars that feed on oak flowers look like oak flowers. In every case, caterpillars that were raised on oak leaves looked like twigs. These results support which of the following hypotheses?

Differences in diet trigger the development of different types of caterpillars.

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.

What was the prevailing notion prior to the time of Lyell and Darwin

Earth is a few thousand years old, and populations are unchanging

Of the following anatomical structures, which is homologous to the wing of a bird?

Flipper of a cetacean

Which pair would have been likely to agree that strata such as those depicted here were deposited gradually over long periods of time by subtle mechanisms that are still at work?

Hutton and Lyell

If 3TC resistance is costly for HIV, then which plot (I—IV) best represents the response of a strain of 3TC-resistant HIV over time, if 3TC administration begins at the time indicated by the arrow

III

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. Lysenkoʹs attempts in this regard were most in agreement with the ideas of

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. Lysenkoʹs attempts in this regard were most in agreement with the ideas of

Which pair would probably have agreed with the process that is depicted by this tree

Lamarck and Wallace

During drought years on the Galapagos, small, easily eaten seeds become rare, leaving mostly large, hard-cased seeds that only birds with large beaks can eat. If a drought persists for several years, what should one expect to result from natural selection?

More small-beaked birds dying than larger-beaked birds. The offspring produced in subsequent

The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?

Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.

Refer to the figure above. Is this population in Hardy-Weinberg equilibrium

No; there are more homozygotes than expected

DDT was once considered a ʺsilver bulletʺ 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.

Which statement best describes the evolution of pesticide resistance in a population of insects?

Offspring of insects that are genetically resistant to the pesticide become more abundant as the susceptible insects die off

To observe natural selectionʹs effects on a population, which of these must be true?

One must observe more than one generation of the population. The population must contain genetic variation.

HIV's genome of RNA includes the code for reverse transcriptase (RT), an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR), an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR. 8) Every HIV particle contains two RNA molecules. If two genes from one RNA molecule become detached and then, as a unit, get attached to one end of the other RNA molecule within a single HIV particle, which of these is true?

One of the RNA molecules has experienced gene duplication as the result of translocation.

Which of the following is not an observation or inference on which natural selection is based?

Poorly adapted individuals never produce offspring

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.

Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree?

Relationships between DNA sequences among the species did not match relationships between skeletal patterns.

Which of the events described below agrees with the idea of catastrophism?

The sudden demise of the dinosaurs, and various other groups, by the impact of a large extraterrestrial body with Earth

In a hypothetical environment, fishes called pike-cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). If a population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely be observed in the algae-eater population over the course of many generations?

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

Which of the following observations helped Darwin shape his concept of descent with modification?

South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe

Which of Darwinʹs ideas had the strongest connection to Darwin having read Malthusʹs essay on human population growth?

Struggle for existence

which of the following statements is an inference of natural selection?

Subsequent generations of a population should have greater proportions of individuals that possess traits better suited for success in unchanging environments

A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. Which inference(s) about this population might be true?

The amount of available food may have increased. The number of predators may have decreased. The squirrels of subsequent generations should show greater levels of genetic variation than previous generations, because squirrels that would not have survived in the past will now survive.

Which of the following statements most detracts from the claim that the human appendix is a completely vestigial organ?

The appendix has a substantial amount of defensive lymphatic tissue.

Refer to the accompanying figure. Recall that eggs from the same female were exposed to each of the eight treatments used. This aspect of the experimental design tested which of the following hypotheses?

The differences are genetic. A female will either produce all flowerlike caterpillars or all twig-like caterpillars.

Some members of a photosynthetic plant species are genetically resistant to an herbicide, while other members of the same species are not resistant to the herbicide. Which combination of events should cause the most effective replacement of the non-herbicide-resistant strain of plants by the resistant strain? 1. The presence of the herbicide in the environment 2. The absence of the herbicide from the environment 3. The maintenance of the proper conditions for one generation 4. The maintenance of the proper conditions for many generations

The presence of the herbicide in the environment The maintenance of the proper conditions for many generations

Members of two different species possess a similar-looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evolution

The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical.

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.

Which statement about natural selection is most correct?

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

Charles Darwin was the first person to propose

a mechanism for evolution that was supported by evidence

If the HMS Beagle had completely bypassed the Galapagos Islands, Darwin would have had a much poorer understanding of the

ability of populations to undergo modification as they adapt to a particular environment.

The theory of evolution is most accurately described as

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

Which variable is likely to undergo the largest change in value resulting from a mutation that introduces a new allele into a population at a locus for which all individuals formerly had been fully homozygous

average heterozygosity

As a young biologist, Charles Darwin had expected the living plants of temperate South America would resemble those of temperate Europe, but he was surprised to find that they more closely resembled the plants of tropical South America. The biological explanation for this observation is most properly associated with the field of

biogeography

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

descent with modification

Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though 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. adaptations to a common

Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though 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. adaptations to a common environment.

Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the Hardy-Weinberg model?

f(A1) = 0.9700, f(A2) = 0.0300

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.

Evolutionary trees such as this are properly understood by scientists to be

hypotheses.

Natural selection is based on all of the following except

individuals adapt to their environments and, thereby, evolv

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence tha

island forms and mainland forms descended from common ancestors.

In Darwinʹs thinking, the more closely related two different organisms are, the

more recently they shared a common ancestor.

Genetic variation _____.

must be present in a population before natural selection can act upon the population

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

no gene flow

For biologists studying a large flatworm population in the lab, which Hardy-Weinberg condition is most difficult to meet?

no mutation

Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvierʹs attempt to explain the existence of

the fossil record.

Which of the following pairs of structures is least likely to represent homology?

the wings of a bird and those of an insect

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.

HIV's genome of RNA includes the code for reverse transcriptase (RT), an enzyme that acts early in infection to synthesize a DNA genome off of an RNA template. The HIV genome also codes for protease (PR), an enzyme that acts later in infection by cutting long viral polyproteins into smaller, functional proteins. Both RT and PR represent potential targets for antiretroviral drugs. Drugs called nucleoside analogs (NA) act against RT, whereas drugs called protease inhibitors (PI) act against PR.

using moderate doses of NA and two different PIs at the same time for several months

Which of the five common ancestors, labeled V—Z, has been least successful in terms of the percent of its derived species that are extant?

w

Which of the five common ancestors, labeled V—Z, has given rise to the greatest number of species, both extant and extinct?

x

which of the five common ancestors, labeled V—Z, has been most successful in terms of the percent of its derived species that are extant?

z