question

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?

answer

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

question

Charles Darwin was the first person to propose what?

answer

A mechanism for evolution that was supported by evidence.

question

In Darwin's thinking, the more closely related two different organisms are, that what?

answer

more recently they shared a common ancestor

question

Natural selection is based on all of the following except what?

answer

individuals adapt to their environments and, thereby evolve.

question

Which statement about natural selection is most correct?

answer

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

question

Given a population that contains genetic variation, what is the sequence of the following events, under the influence of natural selection?

answer

2. A change occurs in the environment. 4. Poorly adapted individuals have decreased survivorship. 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 3. Genetic frequencies withing the population change.

question

During drought years on the Galapagos, small, easily eaten seeds became 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 form natural selection?

answer

More small-beaked birds dying than larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks.

question

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

answer

Genetic variation among individuals.

question

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

answer

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

question

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?

answer

None of the individual insects should have possessed genomes that made them resistant to DDT.

question

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

answer

Flipper of a cetacean (dolphin)

question

If two modern organisms are distantly related in an evolutionary sense, then one should expect that what?

answer

They should share fewer homologous structures than two more closely related organisms.

question

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?

answer

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

question

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

answer

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

question

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

answer

Poorly adapted individuals never produce offspring.

question

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

answer

The wings of a bird and those of an insect

question

Which of these is the smallest unit that natural selection can change?

answer

a population's gene frequency

question

Each of the following has a better chance of influencing gene frequencies in small populations than in large populations, but which one most consistently requires a small population as a precondition for its occurrence?

answer

genetic drift

question

Which is a true statement concerning genetic variation?

answer

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

question

Which describes an African butterfly species that exists in two strikingly different color patterns?

answer

disruptive selection

question

Which describes brightly colored peacocks mating for frequently than drab peacocks?

answer

sexual selection

question

Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this?

answer

directional selection

question

A certain species of land snail exists as either a cream color or a solid brown color. Intermediate individuals are relatively rare. Which of the following terms best describes this?

answer

disruptive selection

question

Heterozygote advantage should be most closely linked to which of the following?

answer

stabilizing selection

question

Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. Tho biological species is the largest unit of population in which successful reproduction is possible.

answer

I and III

question

Males of one species sing only when its predators are absent; males of another species sing only when its predators are present.

answer

behavioral

question

One species lives only in tree holes; another species leaves only in streams.

answer

habitat

question

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 to 14 hours, 15 minutes.

answer

temporal

question

Males of one species are too small to perform amplexus (an action that stimulates ovulation) with females of all other species.

answer

mechanical

question

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?

answer

habitat isolation

question

Rank the following from most general to specific: 1. gametic isolation 2. reproductive isolating mechanism 3. pollen-stigma incompatibility 4. prezygotic isolating mechanism

answer

2, 4, 1, 3

question

Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?

answer

the postzygotic barrier called hybrid inviability

question

The biological species concept is inadequate for grouping what?

answer

asexual organisms

question

Which example below will most likely guarantee that two closely related species will persist only as distinct biological species?

answer

reproductive isolation from one another

question

A rapid method of speciation that has been important in the history of flowering plants is what?

answer

polyploidy

question

Beetle pollinators of a particular plant are attracted to its flowers' bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers become more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occured in this example, and what has driven it?

answer

sympatric speciation, habitat differentiation

question

A hybrid zone is properly defined as what?

answer

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

question

The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is what?

answer

sexual selection

question

According to the concept of punctuated equilibrium, the \"sudden\" appearance of a new species in the fossil record means what?

answer

speciation occurred rapidly in geologic time

question

Which gas was least abundant in Earth's early atmosphere, prior to 2 billion years ago?

answer

oxygen

question

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

answer

II, III, I, IV

question

Which is a defining charateristic that all protobionts had in common?

answer

a surrounding membrane or membrane-like structure

question

RNA molecules can both carry genetic information and be catalytic. This supports the proposal that what?

answer

RNA was the first hereditary information.

question

An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to what?

answer

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

question

Which free-living cells were the earliest contributors to the formation of Earth's oxidizing atmosphere?

answer

cyanobacteria

question

Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?

answer

The oldest fossilized cells resemble prokaryotes.

question

What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? 1. origin of mitochondria 2. origin of multicellular eukaryotes 3. origin of chloroplasts 4. origin of cyanobacteria 5. origin of fungal-plant symbioses

answer

4, 1, 3, 2, 5

question

Which of these observations fails to support the endosymbiotic theory for the origin of eukaryotic cells?

answer

the existence of structural and molecular differences between the plasma membranes of prokaryotes and the internal membranes of mitochondria and chloroplasts

question

The scientific discipline concerned with classifying organisms and determining their evolutionary relationships

answer

systematics

question

Which of these illustrates the correct representation of the binomal scientific name for the African lion?

answer

Panthera leo (italicized)

question

A phylogenetic tree that is \"rooted\" is one

answer

at whose base is located the common ancestor of all taxa depicted on that tree

question

Which of the following pairs are the best examples of homologous structures?

answer

bat wing and human hand

question

Some molecular data place the giant panda in the bear family but place the lesser panda in the raccoon family. Consequently, the morphological similarities of these two species are probably due to what?

answer

possession of analogous structures

question

A taxon, all of whose members have the same common ancestor, is what?

answer

monophyletic

question

When using a cladistic approach to systematics, which of the following is considered most important for classification?

answer

shared derived characters

question

What probably explains the inclusion of rabbits in this research?

answer

They are the outgroup.

question

outgroup

answer

A species or group of species that is closely related to the group of species being studied, but clearly not as closely related as any study-group members are to each other.

question

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of homology?

answer

Dogs and wolves shared a common ancestor very recently.

question

In a comparison of birds with mammals, having four appendages is what?

answer

a shared ancestral character

question

Which of these is the most common compound in the cell walls of gram-positive bacteria?

answer

peptidoglycan

question

Penicillin is an antibiotic that inhibits enzymes form catalyzing the synthesis of peptidoglycan, so which prokaryotes should be most vulnerable to inhibition by peptidoglycan?

answer

gram-positive bacteria

question

gram-positive bacteria

answer

Bacteria that have a thick peptido glycan cell wall, and no outer membrane. They stain very darkly (purple) in Gram stain.

question

gram-negative bacteria

answer

Bacteria that have a thin peptidoglycan cell wall covered by an outer plasma membrane. They stain very lightly (pink) in Gram stain. Gram-negative bacteria are typically more resistant to antibiotics than Gram-positive bacteria.

question

In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures? 1. nucleoid region 2. flagellum 3. endospore 4. fimbriae 5. plasmids

answer

1, 3, and 5

question

Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces? 1. capsules 2. endospores 3. fimbriae 4. plasmids 5. flagella

answer

1 and 3

question

Which statement about the genomes of prokaryotes is correct?

answer

The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleoid region.

question

Which of the following gram-positive prokaryotic cell structure is composed almost entirely of peptidoglycan?

answer

cell wall

question

Which of the following gram-positive prokaryotic cell structures requires ATP to function, and permits some species to respond to taxes?

answer

flagellum

question

Not present in all bacteria, this cell covering enables cells that possess it to resist the defenses of host organisms. What is it?

answer

capsule

question

Which of the following is a structure that permits conjugation to occur?

answer

sex pilus

question

Which of the following is an important source of endotoxin in gram-negative species?

answer

sex pilus

question

Which of the following contains a copy of the chromosome, along with a small amount of dehydrated cytoplasm, within a tough wall?

answer

endospore

question

Regrading prokaryotic reproduction, which statement is correct?

answer

Mutation is a primary source of variation in prokaryote populations.

question

If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is what?

answer

binary fission

question

An organism that obtains its energy from chemicals

answer

chemotroph

question

A prokaryote that obtains both energy and carbon as it decomposes dead organisms

answer

heterotroph and chemotroph

question

An organism that relies on photons to excite electrons within its membranes

answer

phototroph

question

Which of the following traits do archaeans and bacteria share? 1. composition of the cell wall 2. presence of plasma membrane 3. lack of a nuclear envelope 4. identical rRNA sequences

answer

2 and 3

question

Charles and Francis Darwin concluded from their experiments on phototropism by grass seedlings that the part of the seedling that detects the direction of light is the what?

answer

tip of the coleoptile

question

Plants growing in a partially dark environment will grow toward light in a response called phototropism. Choose the incorrect statement regarding phototropism.

answer

Auxin causes a decrease in growth on the side of the stem exposed to light.

question

A plant seedling bends toward sunlight because why?

answer

Auxin is found in greatest abundance on the dark side of the stem.

question

The apical bud of a pine tree inhibits the growth of lateral buds through the production of what?

answer

auxin

question

The ripening of fruit and the dropping of leaves and fruit are principally controlled by what?

answer

ethylene

question

Which one of the following is not a direct function of either auxin or gibberellin?

answer

inducing semescence and ripening

question

Which of the following statements about plant hormones is false?

answer

Abscisic acid generally promotes growth.

question

The plant hormone involved in aging and ripening of fruit it what?

answer

ethylene

question

Plant growth regulators can be characterized by all of the following except that they what?

answer

Function independently of other hormones

question

Buds and sprouts often form on tree stumps. Which of the following hormones would you expect to stimulate their formation?

answer

cytokinins

question

Plant hormones can have different effects at different concentrations. This explains how what?

answer

auxin can stimulate cell elongation in apical meristems, yet will inhibit the growth axillary buds.

question

Auxins (IAA) in plants are known to affect all of the following phenomena except what?

answer

maintenance of dormancy

question

How does indoleacetic acid affect fruit development?

answer

promoting rapid growth of the ovary

question

Which plant hormones might be used to enhance stem elongation and fruit growth?

answer

auxins and gibberellins

question

According to the acid growth hypothesis, how does auxin work?

answer

By increasing wall plasticity and allowing the affected cell walls to elongate.

question

Which plant hormone(s) is (are) most closely associated with cell division?

answer

cytokinin

question

The heavy line in figure 39.1 illustrates the relationship between auxin concentration and cell growth in stem tissues. If the same range of concentrations were applied to lateral buds, what curve would probably be produced?

answer

Curve I

question

If you were shipping green bananas to a surpermarket thousands of miles away, which of the following chemicals would you want to eliminate from the plants' environment?

answer

ethylene

question

Incandescent light bulbs, which have high output of red light, are least effective in promoting what?

answer

phototropism

question

Both red and blue light are involved in what?

answer

stem elongation

question

Seed packets give a recommended planting depth for the enclosed seeds. The most likely reason some seeds are to be covered with only 1/4 inch of soil is what?

answer

The seeds require light to germinate.

question

A short-day plant will flower only when what?

answer

nights are longer than a certain critical value

question

A flash of red light followed by a flash of far-red light given during the middle of the night to a short-day plant will likely do what?

answer

have no effect on flowering

question

Most plants close their stomata at night. What color of light would be most effective in promoting stomatal opening in the middle of the night?

answer

blue

AP Biology Midterm

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards