Biology week 1, 2 reading

If bacteria could not undergo conjugation, they ______

would not be able to generate as much diversity.

Jane is a better tennis player than Jack. If the probability that Jane will beat Jack in any given game is 0.7, what is the probability that they will each win one game if they play two games? (Note that there are two ways they can arrive at this outcome: Jane wins the first game or Jack wins the first game.)

0.42

8). Refer to the table.The relationship between genetic divergence (in sequence divergence) and the extent of reproductive isolation is plotted for three lineages of frogs. Reproductive isolation is measured on a scale ranging from zero representing no isolation, to 1 representing complete isolation. What would be the likely amount of reproductive isolation of frogs in lineage B that have diverged by 4 percent in DNA sequence based on the observed data?

0.45

The FY3 gene plays a role in immune responses in flies. In one population, there are two alleles, and the frequency of one allele is 0.6. If the population is at Hardy-Weinberg equilibrium, what is the frequency of heterozygotes?

0.48

A population of 600 horses has 70 individuals that are AA and 160 that are Aa at a locus involved in immune response. Assuming that these are the only alleles at that locus, what is the frequency of a?

0.75

Scientists measured plankton production in an estuary ecosystem. They filled bottles with water from the same depth in the ecosystem, sealed them to prevent further gas exchange, and submerged them at the depth from which they were taken for a specific amount of time. In "light bottles" (subjected to light), both photosynthesis and respiration occurred. In "dark bottles" (kept in the dark), only respiration occurred. In one test, the study team obtained the following data: Initial bottle: 3 mg C/liter/hour Light bottle: 3.75 mg C/liter/hour Dark bottle: 1.875 mg C/liter/hour Given the equation NPP = GPP - respiration, what is the final value for net primary production (NPP; in mg C/liter/hour) that occurred during this test?

0.75

Refer to the table. The relationship between genetic divergence (in sequence divergence) and the extent of reproductive isolation is plotted for three lineages of frogs. Reproductive isolation is measured on a scale ranging from 0 representing no isolation to 1 representing complete isolation. (Click image to enlarge.) Based on the observed data, what would be the likely amount of reproductive isolation of frogs in lineage B that have diverged by 4% in DNA sequence?

0.84

Suppose researchers know that two species of crab began diverging from a common ancestor when they were separated by the formation of the Isthmus of Panama 6 million years ago. The genetic divergence between these two species at the hypothetical R6 gene is 12 percent. This rate of evolutionary change at this gene in these species is _______ percent per million years.

1

High-throughput sequencing reveals that 30 new mutations have occurred in the coding regions of genes in an individual lizard. If the coding regions of this lizard comprise 150 million nucleotides per haploid genome, what is the mutation rate per nucleotide?

100 per billion

ecall that two hydrogen bonds bind A and T, whereas three hydrogen bonds bind G and C. The stability of DNA is affected by the number of hydrogen bonds, with more bonds promoting more stability. The double-stranded DNA molecule you would expect to have the greatest stability would be one with

15% A.

A pure radioactive substance has a mass of 30 micrograms but had a mass of 240 micrograms 48 years ago. Assuming that the only changes in mass are due to radioactive decay, the half-life of the substance is _______ years.

16

Refer to the figure. (Click image to enlarge.) The diversification of multicellular lineages associated with the Cambrian explosion lasted about _______ percent of the span of time during which life existed before the Cambrian explosion.

2

About _______ years ago, prokaryotes probably first added adequate quantities of oxygen to the atmosphere to allow for the evolution of aerobic cellular metabolism.

2.5 billion

Thirty percent of the bases in a sample of DNA extracted from eukaryotic cells are adenine. What percentage of the bases are cytosine in this DNA?

20

Refer to the graphs. (Click image to enlarge.)The highest NPP would occur under which combination of temperature and precipitation?

27°C and 250 cm

The common ancestor of humans and chimpanzees lived about 7 million years ago. Based on a molecular clock, if a slowly evolving gene shows 3 percent divergence between humans and chimpanzees and 12 percent divergence between humans and gibbons, then humans and gibbons diverged from each other _______ million years ago.

28

Suppose there are two alleles at a locus and that the locus is at Hardy-Weinberg equilibrium. If the frequency of one allele is r, what is the frequency of the heterozygotes?

2r × (1 - r)

One true-breeding line of mice is obese and dark, and the other true-breeding line is lean and light. Dark is dominant to light, but obese and lean exhibit incomplete dominance. The two genes involved are on separate chromosomes. What proportion of offspring from a dihybrid cross should be dark and obese?

3/16

The t locus is involved in the production of tails in a mouse; tt individuals are without tails, whereas TT and Tt have tails. The l locus is involved in the color of tails: assuming that they have tails, individuals that are ll have light tails, whereas all others have dark tails. The two loci are on different chromosomes. In an F2 cross between TTLL and ttll individuals, what fraction will have light tails?

3/16

One true-breeding line of mice is obese and dark, and the other true-breeding line is lean and light. Dark is dominant to light, but obese and lean exhibit incomplete dominance. The two genes involved are on separate chromosomes. What proportion of offspring from a dihybrid cross should be dark and be intermediate between obese and lean?

3/8

Suppose in a population of 250,000 mice the mutation rate per nucleotide for a genetic locus is 4 × 10-8. The locus contains 1,500 nucleotides. How many new mutations should we expect at this locus in each generation?

30

Without DNA repair, the error rate of DNA polymerase is about one for every 100,000 bases replicated. If an organism has a haploid genome of 1.5 billion base pairs, how many mutations would occur each time a diploid cell replicates its DNA?

30,000

Two genes with two alleles each are 30 centiMorgans (map units) apart. A double heterozygote whose parents were homozygous dominant and homozygous recessive is crossed to a double homozygous recessive. What frequency in the progeny will be double homozygotes?

35 percent

Locus A and locus B recombine with 10 percent frequency. Locus A and locus C recombine with 23 percent frequency. Locus B and locus D recombine with 4 percent frequency. Locus D and Locus E are not observed to recombine. Based on this information, what is the expected frequency of recombination between locus B and locus E?

4 percent

If the dominant allele A is necessary for hearing in humans, and another allele, B, located on a different chromosome, results in deafness no matter what other genes are present, what fraction of the offspring of the marriage of aaBb × Aabb will be deaf?

5/8

Suppose you are a genetics counselor who is working with a 21-year-old pregnant woman who has just discovered that her father has Huntington's chorea, a rare dominant autosomal trait. This disease usually develops in middle age, so people carrying this trait do not find out they have this genetic disorder until midlife. What is the chance that she has Huntington's chorea?

50%

Suppose the mutation rate per nucleotide for a genetic locus is 4 × 10-8 and that the locus contains 1,500 nucleotides. What is the per-locus mutation rate?

6 * 10^-5

In Drosophila, the genes for body coloration and eye size are on different chromosomes. Normal-colored bodies are dominant to ebony-colored (very dark) bodies, and normal-sized eyes are dominant to being eyeless. Line A is true breeding for normal body and normal eye, whereas line B is true breeding for ebony bodies and being eyeless. From a dihybrid cross between lines A and B, 400 flies are scored. How many F2 flies are expected to have ebony-colored bodies and normal eyes?

75

In the 1920s, a dye that stained DNA was developed. If this dye showed that DNA was present in 4 units in a gamete of an organism, how many units of DNA would be present in a somatic cell of that organism?

8

You are working with an organism of the genotype AAbbCcDDeeFFGgHHiiJJKKLl. How many different gametes with respect to these genes could this individual produce, assuming no linkage among the different genes?

8

Humans and chimpanzees diverged about 6 million years ago. If 20 nucleotide substitutions have occurred between humans and gorillas, then, according to the molecular clock hypothesis, humans and gorillas separated ___ million years ago.

9

Refer to the figure showing an imaginary name scheme for an undisturbed site with distinct fossil assemblages in the top five layers of strata. (Click image to enlarge.) Imagine that the Ware layer contains abundant and diverse shellfish and other marine fauna, while Sunderland contains the flora and fauna associated with lowland swamps. Which hypothesis is the most logical explanation to account for this?

A global cooling event occurred at the end of the Ware period, lowering sea levels and turning the edge of the sea into a terrestrial habitat.

Scientists are still experimenting to better understand the relationship between species richness, productivity, and stability. But agriculturists have been experimenting with these concepts for millennia, as they try to determine the most efficient ways to grow food. In which of these situations do farmers show the greatest understanding that greater diversity produces a more stable, productive ecosystem?

A grass pasture consisting of 24 grass species

Refer to the figure modeling the theory of island biogeography, which describes how immigration to an island from the mainland and extinction of species on the island interact to determine species diversity. (Click image to enlarge.)According to the graph, which type of island would have the most species?

A large island near the mainland

Aquatic species, such as ocean fish, are particularly vulnerable to overharvesting due to a concept called "tragedy of the commons." When everyone harvests a shared (common) resource, each person tends to harvest as much as possible, because no one owns the resource and there is no motivation to be restrained. This is a particular problem now, with the growing human population and constantly improving technology that makes harvesting fast and efficient. In this situation, which type of fish species would likely be most vulnerable to extinction?

A large species with slow reproduction

Reindeer were introduced to Alaska's remote island of St. Matthew in 1944. They were meant to provide emergency food for 19 Coast Guard members, who abandoned the island when World War II ended in 1945. The reindeer remained on the island, which had an abundance of lichen, their favorite food. They had no predators. Their population started at 29, rose to 6,000, and then crashed to 42 in 1966. Which condition likely does not help explain the drastic change in the reindeer population?

As the population increased, humans overhunted the reindeer population.

Which study would best help scientists predict the future impacts of climate change on wheat production in the United States?

Computer models based on past wheat yields, temperatures, and precipitation

During which event would you find a sex pilus?

Conjugation

Suppose that you are working in a research lab investigating the nature of multicellularity. Which evidence could you gather from two different types of cells obtained from an adult multicellular animal to show that they are specialized?

Differences in genes being expressed

Refer to the table. Groups of 50 house flies were kept in three chambers under the same conditions except for temperature. After 4 hours, the number of surviving flies in each chamber was counted and expressed as a percentage of the initial 50 flies. Incubation Temperature(°C) 5, 25, 45. Survival(%) 85, 100, 15. Which is the null hypothesis that would be developed when using statistics to analyze these results?

Differences in percent survival at the different temperatures could be due to random variations in the samples.

A segment of a food web includes the following interactions: Grass → Grasshopper → Garter snake → Hawk In this example, which interaction has the lowest trophic efficiency, and which trophic level supports the lowest biomass?

Grass → grasshopper; hawk

Warfarin is a popular and potent rodent poison, as well as a blood-thinning medicine. Rats that have one copy of the allele for resistance to warfarin have increased resistance and thus better survival in an environment with warfarin. Rats that are homozygous for this allele are less fit than heterozygotes, even in the presence of warfarin, because they have much higher requirements for vitamin K. Which best describes what occurs in an environment with warfarin? Please choose the correct answer from the following choices, and then select the submit answer button.

Heterozygote advantage

Which scenario best illustrates reinforcement?

Hybrids between two frog species are mostly inviable. When the species come into contact, natural selection favors divergence in the patterns of activity of the species, with one species being active during the day and the other active at night.

Coal burning produces 44 percent of the energy used in the United States and is the single largest producer of air pollution. Among other pollutants, coal-burning power plants are the major source of sulfur dioxide (SO2). What is a major consequence of this coal burning?

Increases acid rain

Refer to the graph showing changes in atmospheric CO2 concentrations in the Northern Hemisphere beginning in 1960. What is the overall trend in CO2 concentration, and what causes the yearly seasonal fluctuations?

Increasing; photosynthesis

Several distantly related lineages of vertebrates have shown decreases in size when they have adapted to living on islands. What is the most likely explanation for this decrease in size?

It arose via convergent evolution.

Refer to the figure. (Click image to enlarge.) A new tetrapod lineage is found that is more closely related to lizards and pigeons than it is to mice. Should the lineage be considered a mammal? Why or why not?

It is not a mammal because the common ancestor of this lineage and the lineage leading to lizards and pigeons was not amnoite.

Which statement is most likely true of a prey animal that has evolved cryptic coloration?

It is palatable to predators.

Refer to the figure showing the tilt of Earth's axis as it revolves around the Sun, causing changes in the seasons. (Click image to enlarge.)Based on the diagram, which statement is true?

It is winter in North America when Earth is at position 2.

An ecologist is studying the relationship between human population growth and loss of habitat in a specific region of a rainforest. Which statement best expresses how this modern-day study differs from historical ecological studies?

It recognizes that we must understand how humans are changing nature.

An imported plant escapes from a greenhouse and begins to grow outdoors. Unnoticed at first, it proliferates and its seeds begin to spread. After several years, it occurs in the wild in several states. The plant grows faster than many native species and is difficult to eradicate. Which is the most likely result of this plant's introduction into the ecosystem?

It will become invasive and outcompete some native plant species.

What is the most likely impact of adding a new (non-native) species to a community?

It will cause direct or indirect effects on many, if not all, species in the community.

Refer to the graph. (Click image to enlarge.)Suppose the r value for the population represented by the curve decreases over time. What would happen

It would move to the right and remain exponential.

A student calculates the amount of plant biomass produced by a field during one season. He defines this as the gross primary production of the field. Is this correct, and why or why not?

No; it represents net primary production, because it does not measure energy lost during respiration.

Population X has 10,000 individuals; population Y has 100,000 individuals. Both have a growth rate of 2 percent. During the first year, how many individuals will be added to each population?

Population A will add 200 individuals and population B will add 2,000 individuals, due to different starting populations.

In their study of diversity and stability in grassland ecosystems, Tilman and his colleagues found that higher species richness in their plots had what effect on stability and productivity?

Productivity and stability of plant production increased, but species composition was not stable.

Before Hurricane Katrina devastated New Orleans in 2005, humans had vastly changed the area. They had destroyed wetlands, extracted oil and gas (which led to sinking of the ground), constructed dams and levees, dredged, and built channels for ship traffic. Also, rising sea levels had caused the death of some cypress swamps. These changes suggest that development of New Orleans destroyed which major ecosystem service that might have lessened the hurricane's devastation?

Protection from flooding

Suppose the actual transforming substance had been found to be protein and not DNA. Which scenario would be expected to produce a transformation that would cause mice to become sick?

Pure protein from S cells added to R cells

In a plant, a single locus affects both berry color and berry size. There are two mutant alleles (R1 and R2) in addition to the wild-type allele (R0). Individuals that are R0R0 have large, white berries. Individuals that are R1R1 or R0R1 have large red berries, individuals that are R2R2 or R0R2 have small white berries, and R1R2 individuals have berries that are both red and small. Thus,

R1 and R2 exhibit codominance.

During succession, two plant species become established at different times. Species A is a perennial with roots that secrete chemicals to maintain a distance between members of the species and similar species. Species B is a low-growing annual with nitrogen-fixing bacteria in its root nodules. Which (if either) of these two species most likely appears first during succession, and why?

Species B likely appears earlier because it facilitates other species by modifying the ecosystem so that later species can colonize.

Which statement about statistical analysis in science is true?

Statistical tests analyze variation and calculate the probability that observed differences in an experiment could be due to random variation.

Refer to the graph showing one of the results from G. F. Gause's classic competition experiment on three species of Paramecium. Both of these species, P. aurelia and P. caudatum, feed on floating bacteria. (Click image to enlarge.)Which statement best describes the relationship between the two species?

They show competitive exclusion, with P. caudatum going extinct.

Refer to the graph showing results from a study on a pathogen that infects and destroys grape plants. The pathogen reproduces asexually to form spores. These spores are easily transported by wind to new plant hosts to begin a new round of infection. In this study, scientists infected grape vine plants with viable spores and placed the plants in a vineyard. The scientists then collected spores that were produced from this infection. They collected some spores at various times on hot, dry days and collected other spores at various times on cool, cloudy days. Then they tested both sets of spores to see how well they caused infection in a new round of host plants. Which statement can be made about this study?

This was a controlled experiment because only one variable differed between the two sets of spores.

Suppose that in a group of flies the mutation rate per nucleotide is about 10 per billion, there are 300 million nucleotides in the haploid genome, and the population size is 40 million. In this case, in every generation _______ new mutations will appear in the population.

about 240 million

Hawaiian honeycreepers (birds), consisting of 50 species, some of which are now extinct, represent a much more diverse lineage than Hawaiian thrushes. Honey creepers have a remarkable variation in bill morphology, whereas Hawaiian thrushes exhibit far less morphological variation. Bill morphology is strongly linked to the resources available for these birds to eat. This suggests that _______ in honey creepers may have occurred as a result of _______.

adaptive radiation; dietary specialization

Consider the case of X-linked inheritance of a recessive mutant allele. Among progeny from a cross of an unaffected male and a heterozygous female carrier,

all male offspring who receive the recessive mutant X chromosome would show the trait.

A study population shows more immigration than emigration. However, researchers studying this population have assumed that these factors are equal. If the per capita growth rate is estimated according to the equation r = b − d, the calculation of r may be

an underestimate.

Scientists describe the recent decline in global biodiversity as Earth's sixth mass extinction. They are having difficulty determining exactly how rapidly species are disappearing, but most scientists fear they are underestimating the rate and number of species being lost. This underestimation would most likely occur because

an unknown number of species have not yet been discovered and described.

The amount of solar energy reaching a given unit of Earth's surface depends primarily on the

angle of the Sun's rays.

At the end of the Permian, populations of organisms were likely to be the most vulnerable to changing climatic conditions

at high elevations.

Male Hawaiian fruit flies of different but closely related species share a geographic range. They have elaborate mating behaviors that involve fighting with other males and stylistic movements to attract females. These behaviors likely arose due to the phenomenon known as

behavioral isolation.

which property of HIV would make it difficult to trace the source of the virus from one person to the next? a) The population of HIV is too small to trace. b) Molecular phylogenies of viruses cannot be constructed. c) The host can have a genetically diverse population of viruses d) The transmission of the virus involves very few (often just one) viral particles. e) HIV evolves very slowly within the host.

c) is correct. the host can have a genetically diverse population of viruses.

Natural selection

can indirectly favor prezygotic barrier development through reinforcement.

The Lord Howe Island stick insect was thought extinct about 1930, after introduced mice and rats eliminated it from the Australian island, its only known habitat. Then, in 2001, scientists found 24 individuals living under a single shrub on an extremely isolated islet in the Pacific. They produced about 1,000 adults and 20,000 eggs through captive breeding, and a captive colony was established on Lord Howe Island. The individuals cannot be released to their former habitat until the rodents have been eradicated, and the Australian government has now initiated a program to do this. The best conclusion that can be drawn from this story is that

captive breeding plus habitat restoration can restore an endangered species.

A species is highly endangered, with a very small breeding population in the wild and a polluted habitat. People interested in preventing the extinction of this species would most likely institute a(n)

captive breeding program to buy time while its habitat is restored.

The Miami blue butterfly was thought extinct since the 1980s, due to habitat loss and fragmentation, but two small isolated populations were recently found in the Florida Keys. There is no migration between the two populations, and effective population size is described as "critically low." Population fluctuations have been seen in recent generations, but there has been no drastic decline in population size. In the near future, the persistence of Miami blue butterfly populations will likely be threatened by all of the following factors except

captive breeding programs.

A group of species in a community all feed on similar resources, and they are all approximately equal in their ability to obtain these resources. Species diversity in this group is likely maintained by

chance or random resource use

Species composition was analyzed for fish communities in two Brazilian rivers. The higher (headwaters), middle, and lower (floodplain) sections of both the Iguatemi River and the Jogui River were sampled. The Iguatemi had 34 species and the Jogui had 31. In both rivers, some species occurred only in the headwaters, others only in the floodplains. Water velocity decreased and turbidity increased from the headwaters to the floodplains. Neither river had rooted vegetation, and the communities did not differ significantly from season to season. The factor most important in determining species composition in the two rivers was most likely

changing characteristics from headwaters to floodplains.

From phylogenetic and other analyses, we now know that HIV entered the human population from

chimpanzees and mangabeys.

Which taxonomic category is the next largest after order?

class

Semiconservative replication of DNA involves

each of the original strands acting as a template for a new strand.

Governments often fail to adopt policies that would encourage sustainable management and protect ecosystem goods and services. This failure happens for all of the following reasons except that

ecosystem services provide little value for the money they would cost.

Which situation best represents the benefits of nonmarket values inherent in the protection of ecosystem biodiversity?

ecotourism

In the Amazon rainforest, deforestation by humans increases hazards around the remaining forest fragments, including fires, hunting, predators, invasive species, and disease. These increased hazards result primarily from

edge effects.

Support for use of the sensory exploitation hypothesis to explain the evolution of female swordtails' preference for swords comes from phylogenetic analysis showing that the swords _______ the female preference evolved.

evolved after

In coral reefs, the cells of the cylindrical coral polyp contain single-celled photosynthetic algae, or zooxanthellae. Coral polyps filter organic material from water and metabolize it, forming carbon dioxide and nitrogenous wastes that zooxanthellae use in photosynthesis. The oxygen and sugars they form in turn are used by coral polyps and dinoflagellates for metabolism. Many corals cannot feed successfully when they lose their zooxanthellae, but zooxanthellae can usually grow and reproduce outside of the corals. For zooxanthellae, this interaction is _______; for corals, it is _______.

facultative mutualism; obligate mutualism

Speciation rates in flowering plants are

faster when the number of different pollinating insects is low.

A windstorm transports a gravid fly to an island. Having only a small subset of the genetic variation in the mainland population, the offspring of this fly are somewhat different from the mainland population. This is an example of

founder effect.

The oldest known _______ were found in the Triassic fossil assemblage

frogs and turtles

Genes located on mitochondrial DNA are usually inherited

from the mother

All the resources required by an organism to maintain its physiological needs determine its

fundamental niche.

From a survey of Martian life, three hypothetical species are found. These are nicknamed krons, furs, and pars. If krons and furs are sister species, the resulting phylogenetic tree will have 45 homoplasies. If krons and pars are sister species, the tree will have 52 homoplasies. Krons and pars have ted body patches, whereas krons and furs have striped bodies. Based on the principles of parsimony, krons and ______ are sister species, ______ a synapomorphy.

furs; and striped bodies is likely

It may be that red hair evolved in Neanderthals and then was introduced into human populations via interbreeding. If this is so, this would be an example of

gene flow

When protected areas or restored ecosystems are too small, they are unable to restore the high diversity present in the original ecosystem. One example of this is seen in the remnants of the tallgrass prairies, which once supported massive herds of bison, elk, deer, pronghorn, and their predators. Now, these massive herds have been reduced to very small populations. When populations reach such low numbers, they become difficult to maintain because of their lack of

genetic diversity.

The leopard can be found in many localities across Africa, Asia, and the Middle East, over an area encompassing 7.7 million square miles (20 million square kilometers). The rare Iriomote cat, by contrast, lives only on Japan's Iriomote Island, an area of 113 square miles (292 square kilometers). These two areas can best be described as the cats'

geographic ranges.

In a pasture, several types of animals (cattle, rabbits, grasshoppers, and geese) all graze on grass. According to ecologists, these organisms are all members of the same

guild

Suppose a population of garter snakes that had not been in contact with newts with TTX was placed with such newts. Assuming that the population persisted, over the course of many generations, we would expect the snakes to _______ in TTX resistance and _______ in speed. Learning Objective 19.6.2 Give an example of an evolutionary trade-off.

increase; decrease

Bluegills in a pond prefer to feed on large zooplankton, such as copepods. The zooplankton in turn feed on algae. The pond has a few bass, which feed on the bluegills. A farmer introduces a large number of additional bass, which decimate the bluegill population. Quickly, algal blooms threaten to overwhelm the pond. The control of algae in this pond is an illustration of a(n)

indirect interaction, because algae are indirectly controlled by bass.

Goldenrod and thistles exude chemicals from their roots that deter the germination and growth of potential competitor plants within their community. This is an example of

inhibition.

Kelp forests in Alaskan waters support numerous species of fish and invertebrates. Giant kelp, the dominant producer in these communities, can be completely decimated by the grazing of sea urchins, which consume the kelp and create "urchin barrens" devoid of marine life. Urchins are a preferred food of sea otters. By keeping urchin numbers low, otters help ensure the viability of the kelp forest community. The first response to removal of sea otters from this community would likely be

initiation of a trophic cascade that decreases kelp abundance.

Consider the following segment of a food web: Grass → Insect → Frog → Snake → Hawk Of these organisms, which is considered the primary consumer?

insect

A major difference between what we define as an ecosystem and what we define as a community is that an ecosystem

involves both energy flow and nutrient cycling.

In a major upwelling region in the eastern equatorial Pacific Ocean, nutrient availability tends to be relatively high, compared with other parts of the ocean. Shortly after an upwelling event, nutrients including nitrogen, carbon, and phosphorus increased, and the region had a short-term phytoplankton bloom. The bloom then stopped until an iron compound was added artificially. This indicates that the region was limited by

iron

12. A researcher interested in production efficiencies hypothesizes that a free-living beetle would have a much higher production efficiency than a social insect such as a termite. This hypothesis is most likely based on the fact that the beetle

is both smaller and a non-social insect.

The relationship between ecosystem type and NPP

is highly variable, with some ecosystems characterized by higher NPP than others.

The rocky intertidal zone on the Washington coast supports a community including a bivalve mussel, Mytilus, which is preyed upon by the sea star Pisaster. If sea stars are removed, the mussel becomes dominant and other space-occupying species, including algae, decline. This suggests that the sea star Pisaster in this community serves as a

keystone predator, indirectly controlling the diversity of the entire community.

Elephants on Africa's Serengeti plains eat small trees, such as acacia, by knocking them over and uprooting them. This behavior keeps the region a grassland rather than a forest or woodland. The grassland sustains large grazers such as antelopes, wildebeests, and zebras, and small mice and shrews. These in turn feed predators such as lions and hyenas. Because of their position in this ecosystem, elephants can be considered a(n)

keystone species.

Meselson and Stahl used heavy nitrogen (15N) in their experiments to

label the original DNA.

The species-area relationship is closely related to the theory of island biogeography. According to the theory of island biogeography, the

larger the island and the closer it is to the mainland, the more species it can support.

Recent studies show that many types of animals besides humans have personalities. Behavioral differences (for example, variations in boldness or aggressiveness) persist across a population over time; that is, different levels of boldness and wariness coexist. Even though a trait for boldness might be dangerous for individuals who possess it, it might be adaptive in a population because, under certain circumstances, the bolder individuals are likely to

lead the population to occupy new territory.

The whole lake fertilization experiments conducted by David Schindler and colleagues in Ontario, Canada, did all of the following except

lead to the conclusion that nitrogen and carbon were not required for algal growth.

The species concept that is best for long-term evolutionary view is the _______ species concept.

lineage

Refer to the phylogenetic tree showing a single viral plaque that was split every 400 generations and grown in the presence of a mutagen. (Click image to enlarge.) Based on this tree, lineage A is as closely related to lineage F is it is to

lineage B.

In tomatoes, tall is dominant to dwarf, and smooth fruits are dominant to hairy fruits. A plant homozygous for both dominant traits is crossed with a plant homozygous for both recessive traits. The F1 progeny are crossed with a homozygous recessive, with the results shown in the table.

linked and show 10 percent recombination.

In tomations, tall is dominant to dwarf, and smooth fruits are dominant to hairy fruits. A plant homozygous for both dominant traits is crossed with a plant homozygous for both recessive traits. The F1 progeny are test-crossed with the following results in the F2 progeny: 96 tall with smooth fruits; 94 dwarf with hairy fruits; 6 tall with hairy fruits; and 4 dwarf with smooth fruits. These data indicate that the genes are-

linked, and show 5 percent recombination

Peeling skin syndrome is a disease in which outer skin tissue peels off in large sheets in affected individuals. This disease has a genetic basis. Research has identified that patients with this disease produce a nonfunctional protein. This protein normally becomes embedded in skin cell membranes and functions in adhesion between cells to hold them together to stabilize skin tissue. Continued investigation into this disease would likely focus on _______ the gene encoding the nonfunctioning adhesion protein in affected patients.

locatiA trait must be heritable so that it is capable of being passed onto future generations.ng the mutation in

Examine this phylogenetic tree of immunodeficiency viruses. Had we had sequences only from HIV-1 and not HIV-2 phylogenetic analysis of HIC\V and nonhuman SIV would have shown that HIV is _______ and SIV is _______.

monophyletic; paraphyletic

Three different alleles (c1, c2, and c3) at the c locus exist in a hypothetical population of juniper trees. If the frequency of c1 is 0.3, what can be said about the frequency of c2?

more information is required to answer this

A hare population ingests local plants and assimilates a percentage of the plant biomass (assimilation = ingestion - excretion). The hares use energy in metabolism as they move, grow, and maintain body temperature. The body tissue they make and the baby hares they produce are available to the local fox population, the main predator of hares. Compared with the amount of energy transferred from plants to hares, the amount transferred from hares to foxes is

much less.

In pea plants, the allele R produces a red flower and is dominant to the white allele (r). A pea plant with red flowers is test crossed, and one-half of the resulting progeny have red flowers, whereas the other half have white flowers. Therefore, the genotype of the test-crossed parent

must be Rr.

A fossil lies buried in Laurasia during the Jurassic period. During its lifetime as a member of the Permian biota, it would most likely have lived in the _______ part of _______.

northern; Pangaea

As people burn fossil fuels, CO2 is released into the atmosphere, and almost half of this excess CO2 dissolves into the oceans, where it forms acidic compounds and lowers the ocean pH. In ecological terms, this process is an example of

nutrient cycling.

Termites live on cellulose from dead wood. They depend on protists in their guts to provide enzymes that can digest wood. Protists would die outside the termites, and the termites would starve without the protists to aid in digestion. This is an example of

obligate mutualism.

The stomach contents of a mammal are examined and found to contain the remains of mice, birds, insects, worms, snails, berries, seeds, grass, and leaves. This organism is therefore a(n)

omnivore.

Members of a conservation organization have funding to establish two protected areas. They can purchase either two 200 km2 parcels of land or one parcel that is 400 km2. Which option (if either) would best meet the goals of a protected area—protecting species and retaining the functions and services of the original ecosystem?

one large parcel, because it would minimize edge effects.

In undisturbed sedimentary rock, strata from the _______ period would be immediately above rocks from the Cambrian.

ordovician

Kemp's Ridley sea turtles nest along a single stretch of the Mexican coast in the Gulf of Mexico. In the 1940s, more than 100,000 turtles came ashore to nest in a single day. In the 1980s, only a few hundred were left, and now they are critically endangered. Initially, Kemp's Ridleys were hunted for meat and particularly for their eggs, almost all of which were taken. Today, survivors are caught in fishing nets and threatened by pollution. This suggests that the major reason the Kemp's Ridley sea turtle is critically endangered is

overharvesting

In the case in which phylogenetic analysis of HIV was used to convict a physician of purposely injecting blood from his HIV-positive patient into his former girlfriend, the victim's HIV sequences were _______ and the patient's HIV sequences were _______.

paraphyletic; monophyletic

Oxpeckers, birds that ride on the backs of grazing mammals, have long been thought to provide benefits to African mammal hosts because they remove and feed on ticks (parasites that embed themselves in the skin of the grazers). However, an experimental study in 2000 suggested that the oxpeckers actually drink the blood from the mammals, with the result that the wounds heal less quickly than if the tick were simply removed. This suggests that oxpeckers may in fact be

parasitic.

From a survey of Martian life, three hypothetical species have been found and nicknamed krons, furs, and pars. If krons and furs are sister species, the resulting phylogenetic tree will have 28 homoplasies. If krons and pars are sister species, the tree will have 22 homoplasies. Krons and pars have red body patches, whereas krons and furs have striped bodies. Based on the principles of parsimony, krons and _______ are sister species, _______ a synapomorphy.

pars; and red body patches is likely

In a study in China, several different varieties of rice were planted in the same field. Crop yields increased by 89 percent compared with fields with a single variety of rice. This occurred because there was a dramatic decrease in disease and the fields remained stable without using pesticides. In addition, the system increased local biodiversity. This is an example of a(n) _______ showing greater productivity and stability than a(n) _______.

polyculture; monoculture

In a coastal aquaculture operation, mussels and seaweed are introduced to use the nutrients contained in the waste produced by salmon. This reduces salmon waste in the system by up to 60 percent. This is an example of a _______ system that is most likely _______ stable compared with a traditional system, in which salmon are farmed alone.

polyculture; more

The major process that occurred on the Pumice Plain on Mount St. Helens in the years after its eruption was

primary succession.

The movement of plates arises from heat generated by _______ coming from the _______.

radioactive decay; mantle

Biologists are studying two populations of lizards, one from the northern end of the lizards' territory and one from the southern end. DNA analysis shows that the northern and southern populations are part of the same lineage, with little differentiation between them. The researchers had expected the two lizard populations to form two distinct lineages because the two ends of the territory had been separated by a river (which had subsequently dried up). However, unbeknownst to the researchers, the northern and southern lizards had failed to generate much reproductive isolation while they had been separated. Hence, the two populations started interbreeding once the river was no longer a barrier. This example illustrates that

reproductive isolation plays an important role in the lineage species concept.

Some invasive species carry pathogens or parasites with them. Scientists think this might be one reason why some introduced species become invasive. Carrying pathogens or parasites might make an invading species more successful if the invading pathogen or parasite

selectively infects and kills native competitors.

The Meselson-Stahl experiment showed that DNA replication is

semiconservative.

Two clades of beetles split off from a node more recently than these clades diverged from other clades. Thus, these clades are _______ clades.

sister

Refer to the graph showing the range of variation among population members for a trait determined by multiple genes. If this population were subject to directional selection for larger size over several generations, which, if any, of the distributions shown would be most likely to result?

slope moving in one direction.

Refer to the figure. According to the figure, which statement best describes the changes undergone by plant communities in the past 9,000 years (9 ka)?

southern forests are tending to move Northward.

A survey of a pond community identified 57 different species that made up the community. This number can best be described as a measure of the community's

species richness.

Refer to the table. The average survival rates of individuals of different sizes in a mouse population were assayed and are presented in the table. Assume that body size is at least partially heritable. Assuming that all other aspects are independent of size, this population is most likely experiencing _______ selection, and the variation in the population should _______ over many generations.

stabilizing; decrease

The size of a particular appendage in many populations of beetles is determined by alleles at many genetic loci and is largely unaffected by selection. Initially, many populations start with about the same average size of the appendage. Assuming that genetic drift is the only evolutionary process operating, we would expect that over the course of many generations, the average size of the appendage would _______ and that there would be _______ difference in the size of the appendage among the different populations.

stay about the same; more

A species of dragonfly arises within the same range where the parent populations are located. This is most likely an example of

sympatric speciation.

In the 1920s, a dye that stained DNA was developed. From this dye, biologists concluded that

the amount of DNA varied among species.

Griffith was able to distinguish two strains of pneumococcus by means of

the appearance of their colonies in culture.

Pacific salmon swim up freshwater rivers to breed. The watershed uphill from the rivers is forested and drains into freshwater streams where the salmon spawn and their young offspring live and grow. Managers calculated that degradation of a specific watershed from its pristine condition resulted in a loss of value of $1.6 million, yet the land was sold for $1 million to developers. This suggests that

the calculated value of the land did not account for the ecosystem services it provided.

Ocean currents influence all of the following conditions except

the forming of trade winds from west to east.

A Nigerian coastal forest is inhabited by five species of small primates, all competing for the same limiting resources. If one primate species becomes locally extinct because of hunting, what will happen to the niches of the remaining species?

the realized niche of at least one species will expand

A researcher stains various types of cells from the same organism, using a dye that stains in direct proportion to the amount of DNA in the cell. You would expect the researcher to find that somatic cells have _______ DNA in their nuclei as the organism's sperm do.

twice as much

According to the phylogenetic tree, salamanders and mice share _____ of the listed synapomorphies.

two (Jaws and lungs)

Epistasis requires

two or more loci.

Xeroderma pigmentosum (XP) is a hereditary disease in which there is a defect in the repair system that repairs DNA after it is damaged by ultraviolet rays. The symptoms of XP are likely due to an _______ repair system.

underactive excision

Prokaryotes probably first added significant quantities of oxygen into the atmosphere when they

used water as the source for ions in photosynthesis.

If the proportion of C in a double-stranded DNA molecule is x, what is the proportion of T?

½ − x

A person standing near the equator experiences a given set of wind circulation patterns in relation to the movement of Earth beneath her. Compared to a person standing near the North Pole, the person at the equator will experience wind that is

deflected to the west and traveling at a slower speed than Earth.

Refer to the figure. (Click image to enlarge.)In the top-down situation shown, what is the relationship between top carnivores (secondary consumers) and the abundance or biomass of primary producers in a food web?

Secondary consumers cause an increase in primary producers.

An ecologist's goal is to maintain the health of an aquatic ecosystem by identifying potentially damaging factors before they cause problems. In her research on a pristine lake ecosystem, she would be most likely to study which topic in the natural setting rather than in a laboratory?

The changing community structure of the lake over time

which statement about this phylogenetic tree is true?

The clade containing the mouse is sister to the clade containing the chimpanzee.

In a population of mockingbirds, the allele G (at a locus with two alleles) is at a frequency of 0.6 and 35 percent of the population is a heterozygote. Assuming that the population is large, which is the most reasonable hypothesis for the pattern?

The population is deviating from Hardy-Weinberg equilibrium due to sexual selection wherein GG individuals prefer to mate with other GG individuals.

What finding would most conclusively rule out the trait being inherited through the mitochondria?

Individual I having an affected daughter

In comparing the terms "species diversity" and "biodiversity," it would be most correct to say that

"species diversity" refers to number of species in a community; "biodiversity" can encompass genes, species, or communities.

In the graph, what is the estimated average rate of amino acid change per 10 million years?

0.018

Whales and pigs diverged about 80 million years ago. If a DNA sequence has had 24 changes between whales and pigs, the rate of change for this sequence would be _______ changes per million years.

0.15

Refer to the table. The relationship between genetic divergence (in sequence divergence) and the extent of reproductive isolation is plotted for three lineages of frogs. Reproductive isolation is measured on a scale ranging from 0 representing no isolation to 1 representing complete isolation. (Click image to enlarge.) Based on the observed data, what would be the likely amount of reproductive isolation of frogs in lineage B that have diverged by 1% in DNA sequence?

0.21

The half-life of a particular radioactive isotope of element X is 100 years. If you know that 500 years ago a fossil contained 10 mg of this isotope, you would expect to find about _______ mg in that fossil today.

0.3

n a haploid bacterium, 720 of 900 individuals have the c1 allele. What is the frequency of the c1 allele?

0.8

Habitat A has a total of 100 birds, with the following numbers of individuals per species: 20, 25, 20, 15, and 20. Habitat B also has 100 birds, with the following numbers of individuals per species: 80, 5, 5, 5, and 5. What is the Shannon index for habitat A?

1.59 H= -(3(.2*ln(.2))+(.25*ln(.25))+(.15*ln(.15)))=1.5968

A girl is born with a genetic defect. DNA analysis reveals that the defect is mitochondrial and is the result of a new mutation, not seen in either parent. what is the probability that she will pass this trait on to her first child, assuming that the mutation is fully penetrant and that the father of the child is unaffected

100 percent

Assuming that the trait is mitochondrially inherited, what is the probability that a child born to C and an affected male will have the trait? Assume that the trait is 100 percent penetrant.

100 percent

If the half-life of a radioactive substance is 800 years, what fraction of the original material is left after 3,200 years?

1/16

In the genetic cross AaBbCcDdEE × AaBBCcDdEe, what fraction of the offspring will be heterozygous for all of these genes (AaBbCcDdEe)? Assume all genes are unlinked.

1/32

Whales and pigs diverged about 80 million years ago. Suppose a DNA sequence has had 48 changes between whales and pigs. The same DNA sequence has had 6 changes between two different species of whales. Assuming a molecular clock is operating, the whale species diverged _______ million years ago.

10

If 28 percent of the bases in a sample of DNA are T, _______ percent must be G.

22

The rules formulated by Erwin Chargaff state that

A = T and G = C in any sample of DNA.

In which situation is the growth rate and size of a population most likely to be limited by space?

A bacterial colony growing in a flask and getting fed periodically

Which situation would most likely result in a temporary life history trade-off in which a rabbit population allocates more of its available energy to obtaining nutrients for survival and less to reproduction?

A drought year in which food is very scarce

Which interaction can correctly be labeled coevolution?

A genetic change in a virus that allows it to exploit a new host, which responds to virus-imposed selection by changing its genetically controlled habitat preferences

Which scenario is least likely to lead to allopatric isolation?

A lake dividing a population of butterflies

Which condition in an ecosystem would be considered a disturbance, as opposed to a stress?

A major flood covers a large floodplain area with water and sediment, killing plants.

A wild mouse population has coexisted for millions of years with Toxoplasma parasites. However, during a recent year, the mouse population was almost decimated by a Toxoplasma infection. What factor most likely explains this sudden change in the pattern of coexistence?

A new, more virulent strain of Toxoplasma emerged.

Which would not be considered an evolutionary trade-off?

A population of a beetle lacking genetic variation for heat tolerance cannot evolve in response to climatic change.

Which effort to preserve biodiversity would be classified as restoration ecology?

A project to convert ranch land into a natural prairie

In which environment would K-strategists most likely be favored over r-strategists?

A rain-forest environment with mild weather and abundant food

Which of these aquatic systems is most likely undergoing eutrophication?

A small lake receiving frequent inputs of partially treated sewage

Coral reefs are found in shallow, coastal, tropical waters. Many species of organisms that might fit well in a coral reef community live some distance away. Which of these organisms would be most likely to colonize the coral reef?

A species that is sessile as an adult but has a free-floating larval stage

Without strict management controls, which of these populations is most likely to be overharvested?

A whale population with a very slow reproductive rate that produces few offspring

In the temperate zone, between approximately 30° and 60° N and S latitudes, a circular air current occurs. Which movement of air at these latitudes causes wet climatic conditions?

Air warms at Earth's surface, then rises, cools, and releases precipitation.

Which statement about traits and phylogeny is true?

All synapomorphies are shared traits.

Which is a major reason that scientists are alarmed by the rapid and massive loss of amphibians?

Amphibians are biological indicators, so their decline suggests as-yet-unknown environmental dangers.

Which of the following would most likely have an effect on temperature that is opposite to that caused by humans burning fossil fuels?

An increase in volcanic activity

Which observation from Darwin's stay in the Galápagos Islands was most instrumental toward his eventual development of evolutionary theory?

Animal species on the islands were endemic to the islands but were similar to species on the South American mainland.

What is the primary distinction between artificial selection and natural selection?

Artificial selection acts on specific traits, regardless of their effect on survival and reproduction.

After maturing in saltwater habitats for about four years, Pacific salmon migrate—at considerable energetic cost—into upstream freshwater river habitats, where they spawn only once before they die. Atlantic salmon, in contrast, return to the sea following spawning and may repeat the migration and spawning pattern several times over multiple years. Which statement about these two species is the most correct?

Atlantic salmon are iteroparous; Pacific salmon are semelparous.

Which is the best example of a coupled human-natural system?

Backyard maintained as a wildlife habitat

Refer to the graphs showing global patterns of changes in NPP with changing temperatures and precipitation. In the boreal forest, or taiga, average annual precipitation is between 20 and 200 cm, depending on location, and the average annual temperature varies between -5°C and +5°C. This suggests that the NPP of the boreal forest is approximately how many mg C/ha/yr?

Between 1 and 5

An ecologist might define a soil ecosystem as all the organisms and interactions involved in transferring nitrogen through the system. She might also define a soil ecosystem as the flow of energy through all the organisms in 2 square meters of soil. Why would both definitions be correct?

Both define subsets of the system that are appropriate for study.

Which of these would not be considered a part of the illegal wildlife trade?

Buying goldfish from a breeder

Refer to the table showing a data matrix of nucleotide positions and species of beetles. Position 1 Position 2 Position 3 Position 4 Position 5 Species A T C A T A Species B A C A T A Species C A C C T C Species D T C A T A Species E A C C T A Species F A G C T C Species F is known to be an outgroup to the five other beetle species. Of species A through E, which species is most likely the sister taxon to all of the other four species?

C

There are three isolated populations of garter snakes: population A has had a constant population size of about 50,000, population B has had a constant population size of about 12,000, and population C has had a constant population size of about 2,000. We would expect to see the greatest fluctuations of allele frequencies in population _______ because this population would experience the _______ genetic drift.

C; most

You have discovered a nonavian dinosaur fossil in a sedimentary stratum with a nearby igneous intrusion. Based on this description, which type of analysis would not be appropriate for this sample?

Carbon-14 dating

6). Refer to the figure showing speciation by centric fusion.Which statement about the figure is false?

Centric fusion between chromosomes 1 and 2 disrupts chromosome pairing during meiosis.

Moving carbon, nitrogen, and other nutrients around the planet, as opposed to moving them locally, is done primarily by which type(s) of processes?

Chemical and geological

The equation ΔN = (B - D) can be used to represent the growth rate of a population. This equation is valid in which situations?

Closed situations where no immigration or emigration is occurring

Which statement best exemplifies Lyell's ideas, which led Darwin to formulate his own views on evolution?

Coastline formation has occurred almost imperceptibly slowly, but it can operate over vast spans of time, even many millions of years.

In what way is an invasive species most likely to harm the community it invades?

Compete aggressively for food with native species

Which of these species or groups would be considered both foundation species and ecosystem engineering species?

Corals in a coral reef ecosystem

A hummingbird conservation group wants to find out more about the birds' ecology. Which hummingbird study would best be described as a landscape-level study?

Correlating dates of hummingbird arrival with dates of flowering along a migration corridor

The nonavian dinosaurs were one group among many that did not survive the _______ mass extinction. A key contributing factor to this event was likely _______.

Cretateous; a meteorite collision

Based on what you know about prevailing winds, which statement correctly defines the winds causing currents 1 and 2?

Currents 1 and 2 are caused primarily by trade winds.

Refer to the chemical formula of dideoxycytidine. The drug dideoxycytidine, used to treat certain viral infections, is a nucleotide made with 2′,3′-dideoxyribose. This sugar lacks -OH groups at both the 2′ and the 3′ positions. (Click image to enlarge.) This drug stops the growth of a DNA chain when added to DNA because

DNA polymerase requires a 3′ end -OH group.

Which statement about DNA replication pertains specifically to synthesis of the leading strand?

DNA replication progresses in the direction of the acting helicase.

In the process of biogeochemical cycling, what is a key distinguishing factor between mineralization and decomposition?

Decomposition breaks down detritus into smaller parts; mineralization breaks down organic compounds into inorganic nutrients.

Of the following types of ecosystems, which one does not receive its energy from the sun?

Deep-sea hydrothermal vents

Which type of selection is most likely to result in an evolutionary trend?

Directional

Suppose there is a failure of the segregation of homologous chromosomes during meiosis. When would this failure most likely occur?

During stage C

A non-native marine mollusk is becoming established in a new environment. In the first years after it arrives, the temperature of the water gradually becomes warmer. Which response to the warming temperature might help the mollusk colonize its new environment?

Earlier age of reproduction, leading to increased reproductive rate

An ecologist is studying the movement of carbon in a pond. She measures concentrations of carbon compounds in various organisms, in the water, and in the sediment. She also measures the rate of carbon flow between groups of organisms, and between organisms and the water and sediment. Is she conducting her study at the community level or at the ecosystem level?

Ecosystem level, because the study involves both abiotic and biotic components

ch. 56

Ecosystems

In the ocean, why would there be a smaller biomass of large predators (for example, sharks and tuna) than of herbivorous animals (for example, some small fish and zooplankton)?

Energy transfer between trophic levels is inefficient.

What is the primary distinction between ecology and environmentalism?

Environmentalism focuses on human concerns, including economics and public policy; ecology focuses on scientific inquiry.

Which is an accurate statement regarding the global distribution of terrestrial biomes?

Every biome is found on different continents in areas having similar climate.

The genes F and G act in accordance with the Dobzhansky-Muller model leading to sterility in hybrids between two species of monkeyflowers. Any combination of the F2 and the G1 alleles causes hybrids to be sterile. Based on the Dobzhansky-Muller model, which genotype was the ancestor of the two species unlikely to have?

F1F1; G2G2

The genes F and G act in accordance with the Dobzhansky-Muller model leading to sterility in hybrids between two species of monkeyflowers. Any combination of the F2 and the G1 alleles causes hybrids to be sterile. First generation hybrids between populations that are F1F1G1G1 and F2F2G0G0 should have the genotype _______ and thus have _______ fitness.

F1F2G0G1; low

A fungus species is observed to undergo asexual reproduction at some times and sexual reproduction at other times. A researcher hypothesizes that the nutrient levels available to the fungus may be responsible for this effect. Which data could be used to test this hypothesis?

Find samples of the fungus growing in the wild, record their reproductive behavior, and collect samples of the substrate they are growing on for chemical analysis.

Which would you not expect to find early in the Devonian period?

Flying insects

Refer to the graphs. Based on the graphs, which conclusion can reasonably be drawn about future extinctions?

Future extinctions are highly likely because 27 percent of assessed species are threatened—perhaps more, as data are deficient for another 16 percent.

In studying a tiny nematode worm, scientists found differences in egg number, egg size, and body mass when the worms were tested at two temperatures. At 12°C, but not at 24°C, the nematodes showed a negative correlation between egg size and egg number. At 24°C, they found a positive correlation between egg size and body mass. They also found genetic correlations for these traits, which varied in the same direction as temperature. What is the strongest conclusion that can be drawn about the contributions of environment and genetics to life history in these nematodes?

Genetics and environment interact to determine expression of the three traits,but their relative importance is not clear.

Which factor does not appear to result in increased speciation rates?

Good dispersal ability

In the example of the two species of Lobelia given in the textbook, one species showed semelparity and the other showed iteroparity. A difference in which factor was most responsible for this difference in life history strategy?

Habitat, which led to differences in probability of survival

Traits in two or more organisms that are similar but not derived from a common ancestor are called ____

Homoplastic traits

Refer to the figure. According to the figure, how does the amount of nitrogen entering the atmosphere from human activities compare with the amount entering from land-based natural sources? (All values are in units of 1012 grams.)

Human: 81; natural: 158

A large city suffers from a major heat-island effect, which is becoming more noticeable as climate change progresses. City planners are considering methods for decreasing the heat-island effect. Which method would likely be most effective?

Increase the number of parks and green roofs.

Two species of protozoa are competing in a laboratory environment. A third species is introduced, with no other changes made to the experimental conditions. The population size of the third species gradually decreases for several days, and then it eventually goes extinct. What is the most likely reason this species went extinct?

It could not compete with the two original species.

Unsustainable fishing, or overharvesting, of many ocean fish species is now occurring. What, if any, is a major ecological impact of this overharvesting?

It damages the entire food web, and recovery of overharvested species is slow.

Black-footed ferret populations declined severely after people began killing off prairie dogs, their main food source. They were listed as endangered, and by 1987, only 18 ferrets were known to exist in the wild. These 18 were put into a captive breeding program, and beginning in 1994, the National Park Service began reintroducing new offspring into the wild. By 2015, there were about 1,000 ferrets in the wild. Based on this information, what is the best conclusion that can be drawn about the ferret captive-breeding program.

It was a success; the species may survive if it can become established in the wild.

Variants in a single gene affect the body size of a fly. Exclusive of predators, what information would be most useful for making predictions about whether and how body size should evolve due to natural selection in this fly population?

Larger individuals have more offspring.

Which scenario presents the greatest challenge to the assumption of a molecular clock?

Lineages of mammals with short generation times evolve faster than lineages with longer generation times.

A large city shows a heat-island effect. At what spatial scale would this be expected to cause temperature changes in the surrounding climate?

Locally, including the city and surrounding countryside

Suppose males of a bird species have much more colorful plumage than the females and that the intensity of red color varies in males. Which would be the best evidence that intrasexual selection was occurring?

Males that are brighter red outcompete paler males for access to females.

The MLH1 protein dimerizes with the PMS2 protein to form a complex that is involved in the correction of errors of DNA replication. Loss-of-function mutations in the genes that encode for these proteins increase the incidence of colon cancer. Which type of DNA error would be repaired by the activity of this complex?

Mismatched bases

The mass extinction at the end of the Cretaceous period eliminated many forms of organisms, producing ecological opportunities for the evolution of new forms. Which group radiated at this time?

Modern and recent forms of mammals

Biologists take multiple measurements of head traits in grasshoppers. They find distinct differences among different populations, and reclassify what had been populations of the same species as several different species. Which species concept are they employing?

Morphological

Suppose proteins, and not DNA, were the genetic material in bacteriophage T2. What would we expect to find in the host cells in the Hershey and Chase blender experiment?

Most of the labeled S

Two species of mice coexist in a community at approximately equal population sizes. A top predator is removed from this community. Quickly, the population size of mouse species A increases, while that of mouse species B decreases. What does this suggest about the species interactions in this community?

Mouse species A has a strong negative effect on mouse species B.

Given that the amount of space on Earth has not changed since Malthus's time, what space-related factor has most enabled the great increase in the carrying capacity for humans?

Much greater crop yields on a given piece of land

Using the symbols to represent positive (+), negative (-), and neutral (0), which correctly represents interactions between species one and species two, respectively?

Mutualism + +; competition - -; predation + -; commensalism + 0; amensalism - 0

During succession at Glacier Bay, Dryas and alders carry out nitrogen fixation, helping spruce trees become established. Established spruce trees then compete for nutrients and light with other tree species, hindering them from becoming established. Should these two interactions be categorized as facilitation or inhibition?

Nitrogen fixation is facilitation; spruce tree competition is inhibition.

Refer to the following two equations that are often used to describe population growth. Nt = N0 + (B - D) + (I - E) ΔN = (B - D) + (I - E) What is the difference between the solutions of these two equations, Nt and ΔN?

Nt is the total population at time t; ΔN is the change in population over a time period.

A forest floor is home to huge numbers of bacteria, fungi, lichens, and small invertebrates such as worms, ants, beetles, and slugs. These organisms carry out decomposition of dead organic matter, which is a key aspect of which process?

Nutrient cycling

Food webs can be regulated by mostly top-down or mostly bottom-up control. Which is an example of mostly bottom-up control?

Nutrients from upwelling control a coastal ocean ecosystem.

Developers are building ten new homes on a parcel of land of one habitat type. Local zoning regulations require that they leave some of the land in its natural condition to conserve native species. They can set aside either one large plot or five small separated plots. The total amount of conserved area is the same in either case. Which choice, if either, would be best for maintaining biodiversity, and why?

One large plot; it would support larger populations and have fewer edge effects.

Which morphological trait would a biologist most likely exclude from use in phylogenetic analysis?

One that is highly subject to environmental modification

Which statement about fossils is false?

Paleontologists have studied a large fraction of the sites that contain fossils.

Which feature is most characteristic of the tundra biome?

Permafrost

The rapid diversification of multicellular organisms occurred in the _______ eon.

Phanerozoic

Compared with an ocean ecosystem, a lake ecosystem is more likely to have which nutrient as its limiting factor for NPP?

Phosphorus

Refer to the table listing the frequencies of an allele (A) at a locus and the average fitness of carriers of that allele at each frequency in four haploid populations. (Click image to enlarge.)The fitness of the other allele (a) is always 0.9, regardless of the frequency of the alleles. In which population can both alleles be maintained?

Population 1

Certain populations of a copepod (a planktonic crustacean) may be reproductively isolated, even though females will mate with any male. Three females from one of the populations were placed with three males from another population. The table shows the results of the experiment. Numbers represent offspring produced by the crosses. Diagonals represent crosses between males and females of the same population. Population 4 shows reproductive isolation from

Population 2 only.

Seagrass beds extend along much of the Atlantic coast of the United States. A group of scientists is studying an estuary that contains seagrass beds. They arbitrarily set a boundary around their study community that includes a 100-yard length of seagrass plus the next 100 feet of water extending from it in all directions. Are the scientists defining their community in theoretical or practical terms?

Practical, because they include a manageable portion of the community

Rising global temperatures increase the rate of evaporation. The warmer air also holds more moisture. These changing factors are most likely to directly affect which process in the hydrologic cycle?

Precipitation

Refer to the table. Individuals of populations of a taxon of mice are collected from various locations at 10-km distance intervals. They are brought back to the lab where mice from different populations are mated. The percentage of crosses that are successful is recorded for each population, along with the percentage of offspring that are fertile from each cross. The data are shown in the table. Which statement about the data shown is most accurate?

Prezygotic and postzygotic isolation are increasing at about the same rate with increasing geographic distance.

Suppose a forest is cut down and replaced with cornfields. How would evapotranspiration rates be likely to change in this situation, if at all?

Rates would decrease, because the corn surface area undergoing evapotranspiration is much smaller than the tree surface area.

When it was established, the U.S. Forest Service instituted a "no fire" policy; they attempted to prevent forest fires and to quickly and completely suppress fires if they started. Their stated purpose was to protect the nation's timber supply. In the 1970s, they reversed this policy and now let some fires burn, especially those that start naturally. In some cases, they even start fires, a process called "controlled burning." What factor caused the Forest Service's reversal of policy on fires?

Recognition that periodic disturbance by fire helps maintain forests

Members of a bird species defend a specific territory during the breeding season. Each breeding pair builds a nest within their territory and feeds its hatchlings from resources inside the territory. The male of the pair warns off others of the species who get too close. This situation represents which type of population dispersion?

Regular

Evidence suggests that some grasses benefit from being grazed. In an asymmetrical grazing interaction, which action of grazers would likely provide the most benefit to a grass species in this ecosystem?

Removing grass blades, allowing the grass more light

The two species of Lobelia living on Mount Kenya live in two different habitats: one on dry, rocky mountain slopes, and one in moist valleys. The mountain species produces vast numbers of small seeds and then dies. The valley species produces fewer but larger seeds, at several different times in its life. These two species vary in which aspect of their life history?

Reproduction

Character displacement, such as the evolution of different-sized beaks in Galápagos finches, relates most closely to which aspect of competition?

Resource partitioning

The succession occurring on the glacial moraines of Glacier Bay, Alaska, and behind other retreating glaciers is considered primary succession. What aspect of this process defines it as primary, rather than secondary, succession?

Retreating glaciers leave bare rock that contains nothing living.

As climate change continues, various species (including dolphins, robins, and finches) are now found in the Arctic, a place where they have not been seen before. What factor is likely responsible for the northern movement of these species?

Rising temperatures

Refer to the figure of chicken combs. In chickens, when the dominant alleles of the genes for rose comb (R) and pea comb (A) are present together (R_A_), the result is a bird with a walnut comb. Chickens that are homozygous recessive for both genes produce a single comb. A rose-combed bird is mated with a walnut-combed bird and produces offspring in the proportion 3 walnut : 3 rose : 1 pea : 1 single. What were the genotypes of the parents?

Rraa and RrAa

Sciurus is the type genus of the squirrel family, which has the scientific name

Sciuridae. (idae means animal family)

An ecologist is studying the growth rate of fish populations in the most pristine, untouched coral reef she can find. The reef is located in a protected natural area where no fishing or other human activities are allowed. What is the most scientifically appropriate way for her to make her study more modern, or "use-inspired"?

Set up a second study site in a fished area, and compare growth rates in the two areas.

Wild-type fruit flies have red eyes. A white-eyed female fly is crossed with a red-eyed male fly. All of the females from the cross are red-eyed and all of the males are white-eyed. What type of inheritance pattern is this?

Sex-linked

Which statement is true?

Sexual selection and genetic drift contribute to the diversity of life.

Which traits are most likely to be considered quantitative?

Slow sprint speed versus fast sprint speed in lizards

Consider the following segment of a food web: Grass → Insect → Frog → Snake → Hawk If the removal of hawks from this part of the food web triggered a trophic cascade, what would be the effects, if any, on the population sizes of snakes and frogs?

Snakes would increase and frogs would decrease.

Refer to the table showing a data matrix of nucleotide positions and species of beetles. Position 1 Position 2 Position 3 Position 4 Position 5 Species A T C A T A Species B A C A T A Species C A C C T C Species D T C A T A Species E A C C T A Species F A G C T C Species F is known to be an outgroup to the five other beetle species. Which two species are most likely to be sister species?

Species A and D

Consider six species of grasshoppers (A-F). Species A, B, and C form a clade. Species D and E also form a clade. The clade containing species A, B, and C is a sister to species F. Which species groups would be a clade?

Species A, B, C, and F

The African savanna is flat and has few hiding places. In this environment, which characteristic is likely to be the greatest asset for a predator?

Speed, to overtake prey

Two closely related beetles are in the same location. They exhibit reproductive isolation, and they are both diploid. Biologists are arguing about which is more likely, that they evolved via sympatric or allopatric speciation. Which statement presents the best argument for what is occurring?

Sympatric speciation is more parsimonious (and thus most likely) because allopatric speciation would require the populations being separated by a barrier, evolving genetic differentiation, and then coming back together.

Interactions between sea anemones and anemonefish were once described as an example of commensalism, but more recently some scientists hypothesize that they might be mutualism. Which behavioral interaction, if correct, would best justify this change in description?

The anemone receives nutrients from the fish's feces, and the fish scavenges food from the anemone.

What would you find at the root of a phylogenetic tree?

The common ancestor of all species depicted in the tree

The Louisiana coast has lost, and continues to lose, many of its wetlands. Much of the loss has resulted from human activity, including building of levees and other flood control structures, carrying out oil exploration and production, and dredging canals for boat traffic. The lost wetlands provided many ecological services, including flood control, fish production, water purification, wildlife habitat, and carbon storage. What factor was most likely not considered when choices were made to replace Louisiana wetlands with human-made structures?

The economic value of ecosystem services provided by wetlands

As sea levels rise because of climate change, some shallow-water marine ecosystems such as coral reefs and seagrass beds will be located in deeper water. What effect will the deeper water likely have on these ecosystems?

The environment will have less light and decreased photosynthesis.

In humans, like most vertebrates, the optic nerve passes through the optic disc of the retina obscuring the visual field. This is literally our blindspot. Cephalopods, like the octopus, do not have such a blindspot because their equivalent of the optic nerve goes behind the retina and does not obscure the visual field. What is the most likely explanation for our blindspot? Learning Objective 19.6.1 Describe how a preexisting trait or set of traits can limit the outcome of selection.

The evolution of traits is constrained by pre-existing historical traits.

Two important marine food webs off the west coast of North America are: Phytoplankton → zooplankton → fish Kelp → sea urchin → sea otter How do these two food webs compare in terms of the primary control of energy flow?

The first has primarily bottom-up control by phytoplankton; the second has primarily top-down control by sea otters.

In a population of 800 wolves, 320 are CC and 360 are Cc for a locus with two alleles. Which statement is true?

The frequency of the C allele is 0.625.

What structural feature of DNA can disrupt the specificity of a protein-DNA interaction?

The genetic material is susceptible to mutations (permanent changes) in the information it encodes.

Grizzly bears eat a variety of both plants (grasses, roots, and berries) and animals (insects, rodents, and fish). How would the NPP of a three-level food web containing grizzly bears compare to the NPP of a three-level food web having no grizzly bears or other omnivores?

The grizzly bear web would most likely have lower NPP.

A field of wildflowers has a diverse community of pollinators. A nearby farmer brings in hives of honey bees to pollinate his fields. The honey bees also feed on wildflower pollen, making them competitors of the wild pollinators. In response, some wild pollinator populations decline, but they build up again when the honey bees are removed. Assuming honey bees are the interactors and wild pollinator species are the targets, what is the most definite conclusion that can be made about interaction strength and direction?

The interactor has a negative effect on some, but not all, target species.

Which latitude-based factor would tend to result in lower extinction rates?

Warm and stable climate

The positions of which two taxa or lineages could be reversed without changing the meaning of the tree?

The lineage containing crocodile and pigeon/ lizard.

Refer to the figure illustrating changes in sea level over time. Asterisks indicate mass extinctions of marine organisms. (Click image to enlarge.) Which statement is supported by the figure?

The permian mass extinction was associated with a severe drop in sea level.

Suppose a doctor is on trial for infecting his wife with a virus obtained from his patients. Which result would most likely clear the doctor of the charges?

The viruses from the victim are closely related to other infected individuals from the general population, but not the doctor's patients.

A conservation group is debating the benefits of working specifically on the protection of an endangered species versus establishing a protected area that encompasses the habitat of that species. Which benefit would be provided only by the protected area option?

The protection and maintenance of multiple species

A heterozygous tall, round-seed plant is crossed to a double-recessive, short, wrinkled-seed plant. What do we call the frequency at which short round seed and tall wrinkled seed are seen in the offspring?

The recombinant frequency

Which statement about model systems is true?

The results of a study of a model organism, such as a fruit fly, might be extended to humans.

The principles of stratigraphy are often used to determine the relative ages of fossils. Which statement is an important assumption of this method?

The sedimentary rocks in which the fossils have been found have not been disturbed.

In Drosophila, production of eye color pigment requires a functional protein encoded by the white locus. Individuals with two copies of the w allele lack any eye color pigment; individuals with at least one wild-type allele have pigment. The bw allele at the brown locus produces a defective enzyme responsible for converting one type of pigment to another. Individuals with two bw alleles have brown eyes; individuals with at least one wild-type allele at the brown locus have normal red eyes (assuming that they have eye pigment). Which of the following statements is true?

The white locus is epistatic to (affects the expression of) the brown locus.

Polar bears hunt seals by traveling over sea ice to areas where seals hunt in the ocean. Seals rarely come to land but use the sea ice to rest, give birth, and raise their pups. Which can be expected to happen to polar bears and seals as the climate warms and the sea ice melts more and more rapidly?

Their populations will decline, and they may go extinct.

What is the main reason why the Rhagoletis flies that prefer apple and those that prefer hawthorn have not collapsed into a single species?

There is no intermediate plant species between an apple and a hawthorn tree.

High species diversity, considered a positive attribute of a community, is measured by both species richness and species evenness. How would higher species evenness likely act as a positive factor in the community?

There would be fewer rare species; thus, there would be more individuals of each species, which could lower extinction risk.

Species able to recolonize the Mount St. Helens area after the volcanic eruption in 1980 had to pass through several "filters" to become established in the ravaged area. What was the most immediate requirement of these species before they could become established?

They had to be part of the regional species pool surrounding the area.

Why do organelle genes tend to have multiple alleles?

They mutate frequently.

Considering food webs in the Konza Prairie of Kansas, an ecologist predicted that in food webs with odd numbers of levels (three or five, for example), grazers would be limited by predators, and plants would thrive (that is, there would be high levels of primary production). Conversely, for food webs with even numbers (two or four, for example), he predicted that grazers would be limited by food, and the landscape would have less plant abundance. If this is correct, the highest NPP would likely be found in a food web having how many levels?

Three or five

Consider four species of conifers. Species A and B are sister species. Species C and D are also sister species. The clade containing species A and B is a sister to the clade containing species C and D. Not counting the root as a node, how many nodes would be found in a phylogenetic tree of species A, B, C, and D?

Two

Which of the following is the shortest period of time?

Two half-lives of 14C

Which situation is most likely to result in the process of coevolution?

Two species in the same environment, with one species preying on the other

Research shows that, compared to nonurban areas, urban heat islands raise nighttime temperatures more than they raise daytime temperatures. What factor shown in the figure might account for this difference?

Urban structures absorb heat during the day and give it off at night.

The pangolin, or scaly anteater, a native of Asia and Africa, is the most trafficked animal in the world. In a single decade, more than a million pangolins were poached and sold for their meat and scales. Which method would conservationists likely use to most rapidly stem the loss of pangolins?

Use CITES to prohibit pangolin sales

Refer to the figure. In the key, "elevated" refers to the addition of CO2 above ambient levels, and "fertilized" refers to the addition of nitrogen fertilizer to the soil. (Click image to enlarge.)Based on these data, can one conclude that nitrogen fertilizer enhances the effect of increased CO2 on NPP in the forest?

Yes; NPP increases when both CO2 and nitrogen are added but increases much less when only CO2 is increased.

Can captive breeding of the California condor be considered a success?

Yes, because the wild population increased from 22 in 1983 to 290 in 2017.

If a high concentration of a particular nucleotide lacking a hydroxyl group at the 3′ end is added to a PCR reaction,

a strand containing that nucleotide will cease to elongate

The sperm of species A dies when it comes in contact with the female reproductive tract of species B. This is an example of the phenomenon known as

a prezygotic isolating mechanism

The vegetable we know as the potato resulted from naturally occurring genome doubling within one species. In other words, the potato has twice as many chromosomes as the ancestor it was derived from. The potato could therefore be described as being the result of the process known as

autopolyploidy

Which statement about molecular clocks is true? a. They can only be used to date very ancient events. b. They can give an average rate of change in an amino acid sequence. c. They cannot predict the order in which evolutionary lineages diverged. d. when different proteins are compared, the slope of the plotted line representing the average rate of divergence is the same for all proteins. e. They do not show the timing of splits between lineages.

b is true. They can give an average rate of change in an amino acid sequence.

According to its scientific definition, a theory is

based on a large body of knowledge.

Unrelated lineages of rodents that moved to islands have increased in size relative to close relatives that are on the mainland. This increase in size is an example of which is a type of _______.

convergent evolution; homoplasy

One strategy considered for preventing introduction of invasive species is deoxygenating ballast water. This strategy is

currently being used successfully in the united states.

Steller sea lion populations in Alaska declined after the 1970s, and survivors were smaller and had lower birth rates. Earlier populations had fed mostly on herring, a fish rich in fat. When herring declined, they fed mostly on cod and haddock, which are larger but lower in fat. This suggests that sea lion population changes can be directly linked to

decline in a high-energy food source.

If the per capita death rate within a population exceeds the per capita birth rate, the population size is

declining.

The Amazon River basin is the world's largest river basin, discharging 20 percent of the water discharged by all rivers around the world. The Amazon's mouth is 150 miles (240 km) wide, and a broad area of forests surrounding the river are flooded every year. This suggests that the topography of the lower part of the Amazon basin is mostly

flat or concave.

The major factor causing carbon dioxide increase in the atmosphere is that

fossil-fuel burning is producing CO2 faster than it can be stored in oceans or on land.

How many nodes are in a phylogenetic tree with five species?

four

Many relatively large ectoparasites, such as leeches and mosquitoes, are only casually associated with their hosts; that is, they feed and then leave. However, whale lice spend their entire lives on one whale. A difference in _______ has most likely caused the evolution of this difference in ectoparasite lifestyle.

habitat (in the ocean, lice would likely be unable to find a new host)

A fern lives in the tropical rainforest and depends on the dense shade of the forest to survive. Then, the rainforest where the fern lives is cut down and replaced with open pastureland, which is warmer and drier. The fern goes extinct. This is an example of biodiversity loss due to

habitat loss

Up to the present, the factor responsible for most of Earth's loss of biodiversity has been

habitat loss and degradation.

Franklin's X-ray crystallography data suggested that DNA

has a helical structure.

Eggs and sperm must contain all the DNA of an organism. To ensure complete DNA, these cells would be expected to

have high levels of telomerase.

All of these mechanisms are examples of a plant defense against herbivory except

high-temperature spray.

Compare the samples of frogs in the two communities. Assume that frogs that appear different are separate species. Compared to pond A, pond B has

higher levels of species evenness and diversity, and equal richness.

Recall the Hillis et al. experiments that tested the accuracy of methods used in phylogenetic analysis. If even more mutagens had been added, the rate of evolution would have been _______, there would have been _______ expected homoplasies, and the accuracy of the phylogenetic analysis most likely would have been _______ than what was observed.

higher; more; worse

A cohort life table allows population ecologists to do all the following except

identify the causes of mortality in a given age class.

A species of mussel is accidentally introduced into ballast water in Europe. The best way to prevent it becoming established at its destination in the United States is to

kill the mussels in the ballast tanks before the ballast water is released.

Depending on the species, a clumped distribution pattern might be adaptive in a population for all the following except

maintaining equal spacing to allow individuals sufficient resources.

Many people think the fungal pathogen Batrachochytrium dendrobatidis, or Bd, is responsible for many of the amphibian declines of the past 20 or more years. However, this connection has not been proven. Scientists think one reason for this may be that

mass mortality events happen rapidly and are usually not observed.

A well-funded team of biologists have collected data on a number of different anatomical features of a group of marine gastropods. Prior work has shown that the rates of evolution of different features vary widely. Based on this, the biologists should use _______ methods in the analysis of their data.

maximum likelihood

All chemical transformations and other work done in an organism contribute to its

metabolism.

Suppose a woman has blood type AB. From this, we can infer that

neither of her parents was type O.

Living plant matter, or biomass, is the currency used to measure the amount of matter available to be used by consumers in an ecosystem. Another term for this biomass is

net primary production

Suppose a man is blood type O. From this, we can infer that

none of his children can be type AB.

Refer to the phylogenetic tree showing the phylogenetic relationships among eight species. Red dots indicate the appearance of derived traits. (Click image to enlarge.) According to the phylogenetic tree, chimpanzee and perch share _______ of the listed

one

The nucleotides that make up a DNA molecule each contain _______ phosphate group(s). Before they are added to the DNA, the precursors to nucleotides each contain _______ phosphate group(s).

one; three

You are studying colorful spiders on the Hawaiian Islands of Oahu, Molokai, Maui, and Hawaii. You discover that populations on these four islands have the same anatomical features but different patterns on their abdomens. You also discover that they share reproductive behaviors and can freely mate with one another, producing viable offspring. Given this information, you conclude that these spiders are _______ species, according to the _______ species concept.

the same; the biological

To prove that DNA is the transforming substance, Avery, MacLeod, and McCarty demonstrated that DNA could transform nonvirulent strains of pneumococcus. The definitive evidence for transformation was

the transformed R bacteria passed on the virulence trait to daughter cells.

Applying the concept of continental drift, if scientists find the same types of fossil pollen in New Zealand and South America, they would probably conclude that

the two continents were once a single continent.

Refer to the table. Individuals of populations of a taxon of salamanders are collected from various locations at 10-km distance intervals. They are brought back to the lab where salamanders from different populations are mated. The percentage of crosses that are successful is recorded for each population, along with the percentage of offspring that are fertile from each cross. Based on this information, which statement is most accurate?

they are not correlated

On a Texas grassland, coyotes (the major predator) preyed on burrowing rodents, which in turn fed on grasses and insects. Managers removed coyotes from the grassland, and a year later the grasses declined in biomass. This sequence of events suggests that control of energy flow in this food web was

top-down, with coyotes in control.

Earth's hot deserts are characterized by extremely low precipitation. Their locations at latitudes approximately 30° north and 30° south of the equator result from

warm equatorial air losing moisture as it rises, then descending due to high pressure at these latitudes.

A conservation biologist is most likely to be concerned about the likely extinction of a species of insects that

was abundant and is now rapidly declining in population.

Regarding its carrying capacity, a well-managed fish population should probably be maintained

well below its carrying capacity, to maximize its growth potential.

Orders are less inclusive than _______ and are more inclusive than _______.

phyla; families

Ch. 55

communities

According to the intermediate disturbance hypothesis, species diversity might be low under conditions of low disturbance or stress because there may be high levels of

competitive exclusion.

DNA proofreading relies upon recognition of correct _______ base pairing by the DNA polymerase complex.

complementary

The pairing of specific bases in the Watson and Crick structure of DNA is known as _______ base pairing.

complementary

The world's highest rates of NPP are found in coral reefs and algal beds. Rates of NPP in tropical rainforests are slightly lower. But rainforests account for much more of Earth's total NPP. This is because rainforests

comprise a much larger percentage of Earth's surface.

_______ enables the specificity of PCR.

The use of particular primers

If both parents have AB blood type, _______ percent of their children would be expected to have type AB blood.

50

In any sample of double-stranded DNA, _______ percent of the bases are purines.

50

The lineage species concept could be represented visually by

branches on a tree.

Sympatric speciation

is common in plants since many plant species can reproduce by self-fertilization.

Which of these ecosystem services could be considered an example of a cultural service?

A beautiful trail through a national park

Which statement about molecular clocks is false?

All DNA molecules evolve according to the same molecular clock.

Which would be the signature that a human virus was acquired from a single animal source?

All human viruses would form a single clade.

Suppose on the hypothetical planet Trantor, a plantlike creature called a zork exhibits the characteristics of blending inheritance. Red zorks that are crossed with other red zorks produce only red offspring. White zorks that are crossed with other white zorks produce only white offspring. White zorks that are crossed with red zorks yield pink offspring. If pink offspring were backcrossed to their red parents, which would be the most likely result?

All individuals would be intermediate between the F1 and their red parents.

Mountain sheep in Southern California are separated into small populations on different mountains within one range. Fenced highways bound two sides of these population areas. Of the small populations in this area, which would be considered part of a metapopulation?

All populations able to move into the habitats of adjoining populations

Two closely related beetles are in the same location. They exhibit reproductive isolation, and they are both diploid. Biologists are arguing about which is more likely, that they evolved via sympatric or allopatric speciation. What statement presents the best argument?

Allopatric speciation is more parsimonious (and thus most likely) because sympatric speciation would require the populations evolving genetic differentiation despite gene flow. Challenge

Which statement about polyploidy is true?

Allopolyploids are hybrid plants that result from the mating of two closely related species.

A coral reef community was destroyed by a combination of dynamiting and poison to harvest fish. The reef area has recently been declared off-limits for fishing, and a conservation group hopes to restore the reef to its initial state. An ecologist thinks the group is unlikely to achieve this goal. Assuming that environmental conditions (such as temperature and acidity) remain the same, what factor is the ecologist most likely considering that would prevent restoration of the reef?

Alternative states may develop in an area, even under similar environmental conditions.

What is the basic distinction between rapid speciation and an adaptive radiation?

An adaptive radiation involves diversification into distinct niches in addition to rapid speciation.

Which situation is most likely to lead to allopatric speciation?

An eight-lane highway divides a population of small salamanders that have limited mobility.

Which factor might best explain why a pathogen infecting a host population often undergoes an initial rapid increase, followed by a decrease?

As the infection spreads, fewer susceptible individuals remain to be infected.

In a salt marsh, marsh grasses carry out photosynthesis. Grasshoppers eat the marsh grasses, blackbirds eat the grasshoppers, and hawks eat the blackbirds. In this example, which organisms are dependent on secondary production?

Grasshoppers, blackbirds, and hawks

The Mid-Atlantic Ridge runs north and south along the bottom of the Atlantic Ocean. Which factor is likely to vary most on the two sides of this ridge?

Benthic (bottom) life

In which list are organisms ordered correctly from lowest to highest trophic level, according to the figure?

Berries, beaver, coyote, gray wolf

A species of brightly colored herbivorous insect enters a new environment. Which factor found in the new environment is most likely to lead over time to a situation involving coevolution?

Bird predators attracted to the insects' color

Refer to the table showing a list of loci of a mustard plant and the frequencies of their most common allele, at different points along geographic distances from a minefield. (Click image to enlarge.)In which is there evidence of a cline?

Both loci B and C because they are linear and fit the horizontal line test

Platyfish with spots have an X-linked gene that produces the spots. All platyfish have an autosomal repressor that inhibits the expression of the spot-producing gene. The closely related swordtail lacks both the spot-producing gene and the repressor. In backcrosses between the two species, some hybrids receive the spot-producing gene, but not the repressor. These individuals can develop malignant tumors, because the expression of the spot-producing gene is not properly regulated. What should we expect for hybrids that lack both the spot-producing gene and the repressor?

Both the females and the males should have high fitness.

Two populations of annelids (worms) live in distinct areas and on different soil types. Researchers are interested as to whether the populations have acquired different types of reproductive isolation. Which method would be best to determine whether two populations exhibited gametic isolation?

Bring them into the lab. Observe single pairs of a male from one population and a female from the other. See whether the sperm from the males of one population will fertilize eggs of the females of the other. If they don't, then they exhibit gametic isolation.

According to the graph, which statement best describes the relationship between total plant cover (a measure of productivity) and number of species (species richness) in test plots?

Greater species richness is associated with greater productivity.

Which correctly lists the order of important first events in the history of life?

Chemical evolution, first archaea, first cyanobacteria, first nucleus, first chloroplasts

Two birds in the American eastern deciduous forest, the nuthatch and the brown creeper, both feed on insects living on tree trunks. As the nuthatch forages, it moves down the trunk. As the brown creeper forages, it moves up the trunk. In this way, the two birds feed on different groups of insects. Which type of competition are the birds exhibiting?

Competitive exclusion

The economic value of pollinator services for U.S. agriculture is billions of dollars per year. Eighty percent of all flowering plant species depend on pollination; insect pollinators are required for most fruit and vegetable crops. However, many pollinators are currently declining because of habitat destruction and pesticide use. What ecosystem-related trade-off has occurred in this situation?

Effective pollination was traded for habitat destruction and pesticide use.

The genes F and G act in accordance with the Dobzhansky-Muller model leading to sterility in hybrids between two species of monkeyflowers. Any combination of the F2 and the G1 alleles causes hybrids to be sterile. Based on the Dobzhansky-Muller model, which genotype should have low fitness?

F2F2; G1G2

The genes H and K act in accordance with the Dobzhansky-Muller model, leading to sterility in hybrids between two species of monkeyflowers. Any combination of the H2 and the K1 alleles causes hybrids to be sterile. Based on the Dobzhansky-Muller model, which genotype should have high fitness?

H1H1; K1K1

Habitat A has a total of 100 birds, with the following numbers of individuals per species: 20, 25, 20, 15, and 20. Habitat B also has 100 birds, with the following numbers of individuals per species: 80, 5, 5, 5, and 5. What is the Shannon index for habitat B?

H= 0.77766~0.78

The Shannon index of species diversity is calculated using this equation. A laboratory community contains four species, with 10, 15, 25, and 50 individuals per species. Using the Shannon index, determine the species diversity of this community.

H= 1.21

In a plant, a single locus affects both berry color and berry size. There are two mutant alleles (R1 and R2) in addition to the wild-type allele (R0). Individuals that are R0R0 have large, white berries. Individuals that are R1R1 or R0R1 have large red berries, individuals that are R2R2 or R0R2 have small white berries, and R1R2 individuals have berries that are both red and small. What are the expected phenotypic ratios if you crossed R1R2 individuals to homozygous wild type?

Half would have small white berries, and half would have large red berries.

Refer to the graph showing the change in human life expectancy since 1840. (Values after 2000, indicated by a dashed line, are extrapolated.) (Click image to enlarge.)Which statement best expresses the reasons behind this continuing increase in life expectancy?

Health care and nutrition have improved greatly, leading to increased life spans within the range of current human genetics.

An ecosystem has very high productivity, abundant rain, and long growing seasons with relatively high temperatures. Strands in its food webs have no more than three or four trophic levels. Which of these factors is least likely to affect the number of trophic levels in the food web?

Humans control all major food webs and maintain the number of levels by predation.

Refer to the table showing four traits for five different hypothetical pairs of salamanders. Species pair Hybrid fitness Dispersal rate (meters/day) Size (grams) Coloration A and B High 0.8 46 Dark C and D Moderate 1.1 23 Light E and F High 1.9 60 Dark G and H Moderate 0.7 29 Light I and J Low 0.5 34 Light All other things being equal, which species pair would likely form the most narrow hybrid zone?

I and J due to the low hybrid fitness

Suppose that a microorganism is discovered on a distant planet. Which investigation could be expected to yield information that could either support or refute the hypothesis that life originated only once in the universe?

Identification of the molecule(s) that encode the organism's biological information

A population of whales is currently growing in number, but had a low population in the past due to hunting. Why would biologists be particularly interested in how much genetic variation exists in the population?

If there is too little genetic variation, the population may have difficulty responding to new challenges.

Refer to the table showing the ancestral and derived traits of five species (A-E). The ancestral state of each trait is indicated by 0, and the derived state is indicated by 1. Species Trait 1 2 3 4 5 A 1 1 1 0 0 B 0 0 0 0 0 C 1 1 0 1 0 D 0 1 0 0 0 E 1 1 0 1 1 Which species (if any) is sister to species E?

Species C

In both crypsis and mimicry, prey defend themselves by trying to make predators not see them as prey. What is a major difference between crypsis and mimicry?

In crypsis, the prey is overlooked; in mimicry, it is noticed.

Because giraffes are large and relatively friendly, they are still often seen on safaris, but conservationists say they are undergoing a "silent extinction." A recent study shows that giraffe populations have declined by at least 30 percent over the last 30 years (three giraffe generations). Due to their declining effective population size, giraffes in the coming years could show which change in population dynamics?

Increased genetic drift

Which factor represents an "abiotic filter" that may prevent a species from becoming established in a marine community?

Increasing ocean acidity

An ecologist is asked to speak in favor of preserving a large tract of natural land, as opposed to rezoning it for development. She decides to emphasize the value of preserving the land for its biodiversity. Given that her purpose is to prevent the land from being developed, which of these arguments would be least acceptable?

It can provide people with timber.

Addition of artificial nitrogen fertilizers to agricultural lands causes an increase in nitrification and denitrification by bacteria. These processes in turn release nitrous oxide (N2O) into the atmosphere. What are the implications of additional nitrous oxide in the atmosphere?

It increases smog and acts as a greenhouse gas.

Which is true about bacterial conjugation?

It involves a conjugation tube.

As atmospheric CO2 levels rise, much of the excess CO2 is absorbed at the ocean surface and enters the ocean ecosystem. What major effect is this absorbed gas having on the oceans?

It is causing ocean acidity to rise.

The morphology and natural history of a common and widely distributed butterfly was observed over a 25-year period in Costa Rica. Recent DNA barcoding (DNA sequence analysis) showed that what was once thought to be a single species is actually a complex of at least 10 species. Though caterpillars of these species eat different food plants and have somewhat different habitat preferences than their adult forms, their morphological differences are subtle. There are no differences in reproductive organs. Based on observation alone, there is no obvious reproductive isolation. Which statement best characterizes how different species concepts would consider this group of butterflies?

It would still be considered one species were it not for the lineage species concept.

Refer to the phylogenetic tree showing the phylogenetic relationships among eight species. Red dots indicate the appearance of derived traits. (Click image to enlarge.) Which synapomorphies are shared by lizards and salamanders?

Lungs and jaws

You begin a study of colorful spiders on the Hawaiian Islands of Oahu, Molokai, Maui, and Hawaii. Examining only their appearance, you discover that populations on these four islands share most anatomical features but have a variety of patterns on their abdomens. Without any further information, you might conclude that these populations are different species, on the basis of which species concept?

Morphological

Two populations of annelids (worms) live in distinct areas and on different soil types. Researchers are interested in whether the populations have acquired different types of reproductive isolation. Which method would be best to determine whether two populations exhibited temporal isolation?

Observe when each population is active. If they are active at different times, then they exhibit temporal isolation.

Refer to the figure. (Click image to enlarge.)What ecosystem do these diagrams represent, and why is the biomass pyramid inverted (with a smaller biomass of primary producers than of primary consumers)?

Open ocean; phytoplankton reproduce very rapidly and support many primary consumers.

Refer to the table. Certain populations of a copepod (a planktonic crustacean) may be reproductively isolated, even though females will mate with any male. Three females from one of the populations were placed with three males from another population. The table shows the results of the experiment. Numbers represent offspring produced by the crosses. Diagonals represent crosses between males and females of the same population. (Click image to enlarge.) Population 4 shows reproductive isolation from

Population 2 only.

In pollination, which characteristic of the plant being pollinated is necessary to attract all pollinators?

Presence of food or other reward

Which application of phylogenetic trees is the most difficult (if not impossible) without assuming a molecular clock?

Providing an estimate of the absolute date when two lineages split

In one region of undisturbed sedimentary rocks, the Feingold stratum is below the Tucos stratum and is above the Ruff stratum. Based on the principles of stratigraphy, the _______ stratum is oldest, and the _______ is youngest.

Ruff; Tucos

Twenty percent of all humans depend on fish as their primary protein source. The United Nations Food and Agriculture Organization (FAO) states that 70 percent of all marine fisheries are now either fully exploited or depleted. Since the mid-1990s, commercial populations of cod, hake, haddock, and flounder have declined by up to 95 percent. Many UN members are calling for action to solve this problem. Which action would be most likely to reverse the trend of declining fish populations?

Setting stricter catch limits, to allow fish stocks to recover

Based on the graph, which is the best comparison that can be made between oceanic and terrestrial ecosystems?

Terrestrial systems show higher NPP at most latitudes, with a large peak at low latitudes.

Imagine that NASA's next probe to one of Jupiter's moons takes a sample from one of its methane lakes. Pictures taken under a microscope reveal a cell-like structure remarkably similar to that of a simple prokaryotic organism. NASA calls it a "Xenop." Based on the textbook's discussion of the common aspects of living organisms on Earth, which of the following pieces of information about the Xenop is paired with its logical conclusion?

The Xenop does not contain genetic information or reproduce and, therefore, is not and never was a living organism.

Leatherback turtles occur in the Atlantic, Pacific, and Indian oceans and migrate among all three oceans. In 1980, there were 115,000 nesting females globally; by 2015, that number had dropped to between 26,000 and 43,000. This decline resulted from poaching for eggs and meat, destruction of nesting sites, accidental catches by fishermen, disorientation of nestlings due to artificial lighting from coastal developments, and more. What does this information suggest about the future of leatherback turtles?

The species may go extinct worldwide if current trends continue.

Refer to the graph showing the average number of parasite species per host, separated by host types. (Click image to enlarge.) Which factor most likely accounts for the great specialization of parasites on trees, as compared with the various animal groups?

The surface areas and volumes of trees are greater than those of animals.

Refer to the figure showing two culture plates. A researcher transfects bacteria with a gene that does not confer a selectable phenotype, so he also includes a gene for resistance to the antibiotic neomycin on a separate DNA strand. After the transfection, the researcher divides the culture into two equal fractions. Fraction 1 is spread onto a plate without neomycin (Plate A), and fraction 2 is spread onto a plate with neomycin (Plate B). Between both plates, how many total colonies are composed of bacteria that have been successfully transfected?

The total cannot be determined.

Refer to the graph showing one of the results from G. F. Gause's classic competition experiment on three species of Paramecium. P. caudatum feeds on floating bacteria; P. bursaria feeds on yeast cells. (Click image to enlarge.)Which statement best describes the relationship between the two species?

They are able to coexist because they are not competing for food.

Ruby-throated hummingbirds migrate as far north as northern Canada in the summer but return to Central America each winter. Migration is extremely energy intensive, and ruby-throats nearly double their body weight (from 3.25 to 6 grams) before migrating. When they reach the Gulf Coast, they weigh only about 2.25 grams. What adaptive advantage do these tiny birds receive by making this stressful, hazardous journey every year?

They avoid local extinctions from cold and lack of food in the winter.

The government must assess a species' extinction risk and decide that it is endangered before it can be placed on the U.S. endangered species list. This usually happens in response to a petition from an environmental group or other agency. Which factor is most likely to cause the government to reject the species (that is, decide not to place it on the endangered list)?

They have insufficient information on the species' recent population numbers.

How would Earth's wind patterns likely differ if there were no Coriolis effect?

They would flow north and south from the equator in straight lines, without separate circulations at different latitudes.

A computer scientist is comparing previous studies of how variants of a virus spread across the range of a population with the spread of pictures in a social media platform. She tells you that she is applying evolutionary theory to track the spread of disinformation on the Internet. Is her usage of "evolutionary theory" correct? Why or why not?

Yes; in her application, she is relying on a body of knowledge about the process of genetic changes in populations.

The genes a, b and c are different genes that reside on the same chromosome. Genes a and b are 10 cM apart, b and c are 2 cM apart, and a and c are 8 cM apart. What is the order of these genes?

a, c, b

A hypothetical ancestral population (AABB) splits into two independent lineages. Mutations produce different new alleles fixed at each loci in each population (AAbb in one population, aaBb in the other). According to the Dobzhansky-Muller model, which genotype would not be viable if the F1 individuals were inviable?

aabb

Climate change is causing many species to move out of their present habitats into new habitats. These migrations are likely happening because of a change in

abiotic environmental conditions.

Refer to the table. (Click image to enlarge.) According to the table, the trend for land-based organisms as air temperatures increase is for

all organisms to move northward or up mountains.

A1 and A2 are different forms of the same gene. Therefore, they are different

alleles.

The proliferation of a large number of descendant species from a single ancestor is known as

an evolutionary radiation.

The poisonous cane toad was introduced to Australia to control cane beetles. It had no effect on the beetles, but in the absence of predators, it has been consuming many other native species. This is an example of

an intended biological control organism becoming a pest, itself.

The Convention on Biological Diversity finds that about 40 percent of the world's economy and 80 percent of the needs of the poor depend on biological resources, that is, biodiversity. This suggests that

biodiversity is vital to all people, and a loss in biodiversity would likely affect everyone.

The genetic diversity of a rocky shore habitat declines precipitously as the climate warms, causing a decline in the number of species present. The decline of species along the rocky shore negatively affects the entire region, including bird populations and shallow offshore habitats. This scenario is best described as a change in the region's

biodiversity.

In the western United States, populations of an annual plant can be found almost continuously from San Diego to Seattle. Even though individuals from the San Diego and Seattle populations never come into contact, they can still be considered part of the same species under the _ species concept because they can potentially interbreed.

biological

In an experiment in a Hawaiian forest, researchers removed all local birds from an enclosure. This resulted in an approximately 80-fold increase in the population of a non-native species of spider. This result suggests that the spider population was being limited by

biotic resistance

A small fish species is accidentally introduced into a large lake. It adapts easily to the lake environment and reproduces rapidly. However, a large native fish species finds it easy prey, and within a few generations, the introduced fish is essentially wiped out. The species was prevented from remaining in the community by the process of

biotic resistance.

Animals were instrumental in helping recolonize during primary succession after the eruption of Mount St. Helens. Based on scientists' observations, those animals most able to help in the early recolonization were those that could

burrow under the pumice and ash.

Examine this phylogenetic tree of immunodeficiency viruses. Based on the figure, which statement about HIV is true? a) The two forms of HIV arose from the same simian species. b) HIV-2 is more closely related to SIV from Sykes monkeys than it it to SIV from sooty monkeys. c) HIV-2 is more closely related to SIV from Sykes monkeys than it is to SIV from African green monkeys. d) HIV in humans forms a clade. e)All HIV variants in humans were derived from viruses in chimpanzees.

c) is correct. HIV-2 is more closely related to SIV from Sykes monkeys than it is to SIV from African green monkeys

A large meteor hit Earth 66 million years ago. As a result, most large animals went extinct, including the nonavian dinosaurs, despite their success for millions of years before that time. This is an example of

differing long- and short-term patterns of evolutionary change.

Refer to the table. The numbers of fledged young from female robins of different sizes were assayed and are presented in the table. Assume that body size is at least partially heritable. [The term "quintile" means one-fifth of a group.] (Click image to enlarge.) Assuming that all other fitness aspects (survival, etc.) are independent of size, this population is most likely experiencing ______ selection, and the population should _______ in size over many generations.

directional; increase

An animal species has the potential to become a member of a natural community forming in an area that is recovering from a massive hurricane. To become established in the new community, the first requirement is that the species must be able to

disperse into the new habitat.

The branches and canopy of fig trees in tropical rainforests provide habitat for several thousand animal species, including insects, reptiles, birds, and rodents. Their fruit serves as a food source for many species during times of the year when other fruit is scarce. These fruit-eating species in turn provide prey for many different predator species. The benefits provided by fig trees suggest that, in the rainforest, they serve as

foundation species

Which investigator(s) studying DNA collected data that could be used to infer the positions of atoms in DNA?

franklin

You are a lab assistant working with Drosophila. You suspect that vestigial-winged flies may have contaminated a vial of wild-type flies. You know that vestigial wings are recessive to the wild type. The best way to tell whether a male fly with normal wings taken from the questionable vial is homozygous wild type is to mate it to females that you know are _______. The male is homozygous wild type if _______.

homozygous for vestigial wings; all the offspring have wild-type wings

A conservation biologist is promoting the preservation of a wilderness site that includes a stand of old-growth forest. She emphasizes the age of the trees and the importance of preserving this ancient ecosystem for future generations. She states that "it is the right thing to do." This scientist is arguing that biodiversity (as exemplified by this ancient forest) is important because

humans have an ethical obligation to work for conservation and against extinction.

Suppose allopatric speciation is the most prevalent mode of speciation. Under this condition, you would you expect many closely related species not to be found adjacent to one another

in highly mobile species.

Organisms most likely to tolerate harsh abiotic conditions are found

in the earliest stages of succession.

At the surface of the oceans, NPP is most often limited by nutrients, particularly nitrogen and iron. Moving downward through the ocean, the major limiting factor is usually

light

Today, Earth is said to be undergoing a sixth mass extinction event, the first (and only) one caused by humans. This mass extinction event can best be distinguished from Earth's background extinction rate by considering the

number of extinctions occurring per year.

In bacteria, circular DNA molecules that replicate independent of the main chromosome are known as

plasmids.

The genetic disease blue sclera is determined by an autosomal dominant allele. The eyes of individuals with this allele have blpleiotropy.uish sclera. These same individuals may also suffer from fragile bones and deafness. This is an example of

pleiotropy.

ch. 53

population

The habitat and food requirements of grizzly bears and black bears are similar but not identical. A study in British Columbia examined predicted versus actual distributions of these two species using hair traps and DNA analysis of the hair to determine whether black bears or grizzly bears were using particular areas. Most of the area was suitable for both species, but black bears mainly occurred in valley bottoms and open habitats, whereas grizzly bears occurred in more closed habitats (forest) at higher elevations. The lack of overlap in habitat suggests that the two bear species are practicing

resource partitioning.

The _________ of a phylogenetic tree represents the common ancestor, the ________ represent places where lineages diverge, and the ______ axis represents time. (Assume that the tree is oriented as depicted in the textbook.)

roo; nodes; horizontal

Darwin's finches are thought to have evolved as a result of allopatric speciation. This is mainly based on the observation that

the islands are far enough apart that movement between islands was limited.

An evolutionary biologist is trying to determine if three different populations of damselflies are separate species based on observations of the individuals with which these damselflies will mate. All combinations of individuals from the populations are able to mate with one another but none of the combinations among different populations produce offspring. According to these observations, there is/are _______ damselfly species, and the biologist is employing the _______ species concept.

three; biological

Carbon dioxide and other greenhouse gases are important factors in Earth's atmosphere because they

trap heat radiating toward space from Earth's surface.

Removal of a keystone species from a community will likely decrease species richness by interrupting

trophic interactions