Unit 4 Quiz (combined)

Question 1

Which of the following would most quickly be eliminated by natural selection?

a harmful allele in an asexual, haploid population

a harmful recessive allele in a sexual, diploid population

a harmful recessive allele in a sexual, polyploid population

any harmful allele, regardless of the system of inheritance in a population

Answer 1

a harmful allele in an asexual, haploid population

Question 2

Tay-Sachs is inherited as an autosomal recessive allele. Homozygous individuals die within the first few years of life. However, there is some evidence that heterozygous individuals are more resistant to tuberculosis. Which of the following statements about Tay-Sachs is true?

The allele for Tay-Sachs is always selected against.

This situation is an example of heterozygote advantage if tuberculosis is present in a population.

This situation is an example of disruptive selection.

Heterozygotes will be more fit than either homozygote regardless of environmental conditions.

Answer 2

This situation is an example of heterozygote advantage if tuberculosis is present in a population.

Question 3

Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to

Answer 3

maintain two phenotypes in a dynamic equilibrium in a population.

Question 4

A group of ants escaped from a picnic basket carried to the top of a mountain and thrived in this area where there were no other ants. Many years later descendants of these ants crawled into a picnic basket on the mountain and traveled back to the valley from which their ancestors had come. Which of these observations would cause you to conclude that the ants on top of the mountain had become a different species from those in the valley?

The mountain ants and valley ants were different colors.

The mountain ants and valley ants were different sizes.

The mountain ants ate different food than the valley ants.

The mountain ants could not mate with the valley ants.

Answer 4

The mountain ants could not mate with the valley ants.

Question 5

Genetic differences between populations tend to be reduced by

Answer 5

gene flow.

Question 6

Darwin found that many of the species on the Galápagos Islands

Answer 6

resembled species on the nearest mainland.

Question 7

Geological evidence indicates that two landmasses, separated by a deep ocean channel, have been moving apart since 45 million years ago. You are studying a group of organisms that has widespread populations on both of the landmasses. Which is the most likely hypothesis for the group’s evolutionary history?

The group’s ancestors were definitely present on the original landmass.

The group’s ancestors cannot have been present on the original landmass.

If the group’s ancestors could not move across the open ocean, it is very likely that they were present on the original landmass.

The group’s ancestors must have independently colonized each of the landmasses from a third location within the past 45 million years.

Answer 7

If the group’s ancestors could not move across the open ocean, it is very likely that they were present on the original landmass.

Question 8

Two populations that have been separated by a river are most likely to become separate species if

Answer 8

genes controlling molecules on the surface of the sperm that bind with egg receptors are different in the two populations.

Question 9

Two species that occasionally mate and produce zygotes, but that have incompatible genes that prevent the resulting embryo from developing, are affected by

Answer 9

reduced hybrid viability.

Question 10

Most polyploid species arise from

Answer 10

the hybridization of two parent species.

Question 11

Mass extinctions

Answer 11

remove well-adapted species and groups from the Earth, so that it may take millions of years for species diversity to recover.

Question 12

Frequently, a group of related species will each have a unique courtship ritual that must be performed correctly for both partners to be willing to mate. Such a ritual constitutes a ________ and ________ reproductive barrier.

Answer 12

behavioral; prezygotic

Question 13

Which of the following would a biologist describe as microevolution?

the formation of new species

the extinction of species

dramatic biological changes, such as the origin of flight, within a taxon

a change in the gene pool of a population from one generation to the next

Answer 13

a change in the gene pool of a population from one generation to the next

Question 14

In the chiclid populations in Lake Victoria, what trait in females acted as a selection factor on which males they mated with?

Answer 14

color vision

Question 15

The Mesozoic era is often called the age of reptiles. Which of the following also occurred during this era?

the origin of animals in the oceans

the appearance of the first plants on land

the appearance of the first animals (tetrapods and insects) on land

the appearance of the first mammals and flowering plants on land

Answer 15

the appearance of the first mammals and flowering plants on land

Question 16

The example of ocean and lake stickleback fishes indicates that morphology can be altered by

Answer 16

altering the expression of a gene that is associated with development in only some parts of the body.

Question 17

Over a span of several thousand years, a number of species show adaptations to climate change: Drier, warmer conditions select for succulent vegetation and deep taproots in plants, burrowing in mammals and amphibians, and other similar adaptive changes. What could be predicted to happen if the climate shifts in the opposite direction and becomes progressively wetter and cooler?

Answer 17

Different adaptive trends will probably be favored in the new climatic environment.

Question 18

Structures that evolved from the same structure in a common ancestor are

Answer 18

homologous.

Question 19

A farmer decides to go into the business of raising trout for tourists who enjoy fishing. She builds six trout ponds and stocks each of them with trout from genetically identical stock. Her friends tell her that because she started each pond with just a few trout, she has created a bottleneck effect and her trout populations are likely to become genetically different rapidly. Which of the following statements about her trout is likely true?

Because they are all genetically alike, they will all remain alike even though the ponds are different.

Because each population started off genetically identical, any mutation that occurs in one pond will also occur in the others.

Because the ponds are different and the populations are likely to experience different mutations, the populations will likely diverge evolutionarily, but only over many generations.

The increase in genetic diversity caused by sexual reproduction will promote evolutionary divergence over time.

Answer 19

Because the ponds are different and the populations are likely to experience different mutations, the populations will likely diverge evolutionarily, but only over many generations.

Question 20

Which of the following thinkers argued that much of human suffering was the result of human populations increasing faster than food supply, an argument that later influenced Charles Darwin’s ideas of natural selection?

Answer 20

Thomas Malthus

Question 21

Sympatric speciation commonly occurs through ________ in plants but is more likely to occur through ________ in animals.

Answer 21

polyploidy; habitat differentiation and sexual selection

Question 22

Mate-attracting features such as the bright plumage of a male peacock result from

Answer 22

intersexual selection.

Question 23

A population of 1,000 birds exists on a small Pacific island. Some of the birds are yellow, a characteristic determined by a recessive allele. The others are green, a characteristic determined by a dominant allele. A hurricane on the island kills most of the birds from this population. Only 10 remain, and those birds all have yellow feathers. Which of the following statements is true?

Assuming that no new birds come to the island and no mutations occur, future generations of this population will contain both green and yellow birds.

The hurricane has caused a population bottleneck and a loss of genetic diversity.

This situation illustrates the effect of a mutation event.

The 10 remaining birds will mate only with each other, and this will contribute to gene flow in the population.

Answer 23

The hurricane has caused a population bottleneck and a loss of genetic diversity.

Question 24

Scientists hypothesize that a major factor promoting the adaptive radiation of mammals was probably

Answer 24

the mass extinction of most dinosaurs.

Question 25

Scientists evaluating the Cretaceous mass extinction have concluded that

Answer 25

an asteroid impact was probably the triggering event for the extinction.

Question 26

Two species interbreed occasionally and produce vigorous, fertile hybrids. When the hybrids breed with each other or with either parent species, however, the offspring are feeble or sterile. These species are affected by

Answer 26

hybrid breakdown.

Question 27

In a large population of plants, notches in the leaves are caused by a dominant allele N and lack of notches by a recessive allele n. Over many generations the proportion of plants in the population with notched leaves increases. What is the most likely cause?

Answer 27

Directional selection favored plants with notched leaves.

Question 28

What was the probable role of oxygen gas in the early stages of life’s appearance on Earth?

Answer 28

Oxygen gas tends to disrupt organic molecules, so its absence promoted the formation and stability of complex organic molecules on the early Earth.

Question 29

When plants undergo allopatric speciation, an initial reproductive barrier is often

Answer 29

pollinator choice.

Question 30

The findings of Pasteur and others have established that

Answer 30

life does not arise from nonliving matter today, but in the conditions of early Earth, such an event could have occurred.

Question 31

Geologists have evidence that over the past 1.5 billion years

Answer 31

Earth’s landmasses have joined into a single continent and split back apart again on three occasions.

Question 32

Large antlers in male elk, which are used for battles between males, are a good example of a trait favored by

Answer 32

intrasexual selection.

Question 33

Speciation without geographic isolation is called ________ speciation.

Answer 33

sympatric

Question 34

Which of the following types of reproductive barriers separates two species of sea cucumbers whose sperm and eggs often bump into each other but do not cross-fertilize because of incompatible proteins on their surfaces?

Answer 34

gametic isolation

Question 35

The emergence of many diverse species from a common ancestor is called

Answer 35

adaptive radiation.

Question 36

Miller-type experiments have shown that

Answer 36

complex organic molecules can be produced by physical processes from inorganic components.

Question 37

The emergence of many diverse species from a common ancestor is called

Answer 37

adaptive radiation.

Question 38

Miller-type experiments have shown that

Answer 38

complex organic molecules can be produced by physical processes from inorganic components.

Question 39

Which of the following types of reproductive barriers separates a pair of moth species that could interbreed but for the fact that the females’ mating pheromones are not attractive to the males of the other species?

Answer 39

behavioral isolation

Question 40

Over a span of several thousand years, a number of species show adaptations to climate change: Drier, warmer conditions select for succulent vegetation and deep taproots in plants, burrowing in mammals and amphibians, and other similar adaptive changes. What could be predicted to happen if the climate shifts in the opposite direction and becomes progressively wetter and cooler?

Answer 40

Different adaptive trends will probably be favored in the new climatic environment.

Question 41

Which of the following types of reproductive barriers separates a pair of moth species that could interbreed but for the fact that the females’ mating pheromones are not attractive to the males of the other species?

Answer 41

behavioral isolation

Question 42

How can the success of one group of organisms promote the adaptive radiation of a second group?

Answer 42

by providing new food resources, habitats, etc. for the second group to utilize

Question 43

Microevolution, or evolution at its smallest scale, occurs when

Answer 43

a population’s allele frequencies change over a span of generations.

Question 44

Which of the following will tend to produce adaptive changes in populations?

Answer 44

natural selection

Question 45

Uplift and formation of a mountain range divide a freshwater snail species into two isolated populations. Erosion eventually lowers the mountain range and brings the two populations together again, but when they mate, the resulting hybrids all produce sterile young. This scenario is an example of

Answer 45

allopatric speciation.

Question 46

A population is

Answer 46

a group of individuals of the same species that live in the same area and interbreed.

Question 47

When plants undergo allopatric speciation, an initial reproductive barrier is often

Answer 47

pollinator choice.

Question 48

The biological species concept is

Answer 48

sometimes difficult to put into practice even for present sexual organisms and useless for asexual organisms and fossils.

Question 49

At the end of the ________ period, over 96% of marine species and many terrestrial species became extinct, possibly because intense volcanic activity warmed Earth’s climate.

Answer 49

Permian

Question 50

A spot where two continental plates are sliding past one another may be prone to

Answer 50

earthquakes.

Question 51

Darwin found that many of the species on the Galápagos Islands

Answer 51

resembled species on the nearest mainland.

Question 52

At the end of the ________ period, over 96% of marine species and many terrestrial species became extinct, possibly because intense volcanic activity warmed Earth’s climate.

Answer 52

Permian

Question 53

Which of the following statements about the Galápagos finches is false?

The Galápagos finch species differ in their feeding habitats.

Each island in the Galápagos chain has one and only one isolated, unique species of Darwin’s finch.

Most speciation events of the Galápagos finches occurred when some finches made it to another island, evolved in isolation, and accumulated enough changes to become a new species.

The evolution of the Galápagos finches is an excellent example of adaptive radiation.

Answer 53

Each island in the Galápagos chain has one and only one isolated, unique species of Darwin’s finch.

Question 54

Which of the following types of reproductive barriers separates two flowering plant species that could interbreed but for the fact that one has a deep flower tube and is pollinated by bumblebees whereas the other has a short, narrow flower tube and is pollinated by honeybees?

Answer 54

mechanical isolation

Question 55

Cave-dwelling catfish and cave-dwelling salamanders share striking similarities: Both organisms lack pigmentation, and their eyes are reduced or absent. The most recent common ancestor to these organisms had normal pigmentation and fully developed eyes. The similarities between cave catfish and cave salamanders are an example of

Answer 55

analogy.

Question 56

Which of the following descriptions best represents the gradual model of speciation?

Speciation occurs regularly as a result of the accumulation of many small changes.

An isolated population differentiates quickly from its parent stock as it adapts to its local environment.

Speciation occurs under unusual circumstances and therefore transitional fossils are hard to find.

Species undergo little change over long periods interrupted only by short periods of rapid change.

Answer 56

Speciation occurs regularly as a result of the accumulation of many small changes.

Question 57

Brown-eye genes are dominant over blue-eye genes. What is the best explanation for the fact that all the blue-eye alleles have not disappeared in the human population?

Answer 57

The population is likely in Hardy-Weinberg equilibrium for that locus.

Question 58

Over a span of several thousand years, a number of species show adaptations to climate change: Drier, warmer conditions select for succulent vegetation and deep taproots in plants, burrowing in mammals and amphibians, and other similar adaptive changes. What could be predicted to happen if the climate shifts in the opposite direction and becomes progressively wetter and cooler?

Answer 58

Different adaptive trends will probably be favored in the new climatic environment.

Question 59

In the axolotl, development is altered. Adult axolotls retain features (external gills and aquatic life) that were juvenile in its ancestors, a phenomenon known as

Answer 59

paedomorphosis.

Question 60

One of the strongest lines of evidence of a meteor or comet impact in the late Cretaceous is

Answer 60

a thin layer of iridium-enriched clay in late Cretaceous fossil strata.

Question 61

The ________ suggests that speciation occurs in brief spurts.

Answer 61

punctuated equilibrium model

Question 62

Some butterflies can ingest toxic chemicals from the milkweed plants they feed on and then can store those chemicals in their body. Because toxins stored in the butterflies are toxic to birds, the birds avoid eating the butterflies. Which of the following is the best explanation for this situation?

Answer 62

Any butterfly allele that allowed milkweed toxin storage would be likely to persist because butterflies that had it were more likely to survive.

Question 63

It is estimated that the modern continents began to take shape

Answer 63

66 million years ago.

Question 64

One of the strongest lines of evidence of a meteor or comet impact in the late Cretaceous is

Answer 64

a thin layer of iridium-enriched clay in late Cretaceous fossil strata.

Question 65

Organisms that possess more than two complete sets of chromosomes are said to be

Answer 65

polyploid.

Question 66

Humans share several features with salamanders. Certain genes and proteins are nearly identical between the two species; both species have four limbs with a similar skeletal structure; the species’ early embryos are similar; and where the salamander has a functional tail, humans have a vestigial tailbone. In evolutionary terms, these are examples of

Answer 66

homology.

Question 67

What evidence is used to determine the branching sequence of an evolutionary tree?

Answer 67

anatomical or molecular homologous structures

Question 68

The emergence of a new plant species over a brief period of time followed by a long period of little change is consistent with which of the following theories?

Answer 68

punctuated equilibrium

Question 69

The process through which species not closely related may come to resemble one another if they live in a similar environment is known as

Answer 69

convergent evolution.

Question 70

Which of the following options lists major events in the history of life on Earth in the proper order, from earliest to most recent?

Answer 70

first prokaryotes, photosynthesis, first eukaryotes, colonization of land by plants and fungi

Question 71

Which highly reactive gas was probably absent from the Earth’s primitive atmosphere?

Answer 71

oxygen

Question 72

Most polyploid species arise from

Answer 72

the hybridization of two parent species.

Question 73

Which of the following assumptions or observations is not part of Darwin’s idea of natural selection?

Answer 73

Whether an organism survives and reproduces is almost entirely a matter of random chance.

Question 74

One of the finest available sequences of fossils shows how horses have changed slowly and by subtle steps from small, shrub-browsing ancestors to the large, grass-grazing modern horse. A large number of fossil species have been named, and it is often difficult to decide on the identity of a fossil horse because transitional forms are common. This record of evolution best fits the idea of

Answer 74

the gradual model of speciation.

Question 75

Plants and fungi first became established on land during the

Answer 75

Paleozoic

Question 76

Which of the following represents a pair of homologous structures?

Answer 76

the wing of a bird and the front legs of a horse

Question 77

Which of the following types of reproductive barriers separates a pair of insect species that could interbreed but for the fact that one lives on goldenrod plants and the other on autumn daisies in the same general area?

Answer 77

habitat isolation

Question 78

Scientists hypothesize that a major factor promoting the adaptive radiation of mammals was probably

Answer 78

the mass extinction of most dinosaurs.

Question 79

Which of the following would tend to promote adaptive radiation?

Answer 79

An organism colonizes an isolated area that is habitable but relatively devoid of life.

Question 80

Genetic drift resulting from a disaster that drastically reduces population size is called

Answer 80

the bottleneck effect.

Question 81

Which of the following statements regarding fins on fishes is true?

Answer 81

Fins are an adaptation that aid in swimming.

Question 82

Geologists have evidence that over the past 1.5 billion years

Answer 82

Earth’s landmasses have joined into a single continent and split back apart again on three occasions.

Question 83

Blue-footed boobies have webbed feet and are comically clumsy when they walk on land. Evolutionary scientists view these feet as

Answer 83

the outcome of a trade-off: Webbed feet perform poorly on land but are very helpful in diving for food.

Question 84

In which of the following situations would speciation be most likely to occur?

A population of juniper shrubs is split in two by a canyon. Every year, strong winds carry a small amount of the shrubs’ pollen across the canyon.

A Japanese mollusk species whose larvae are often carried from port to port in ship bilge (waste) water now flourishes in San Francisco Bay, a busy commercial port.

Bighorn sheep occupy mountains from Canada to Death Valley in Southern California, interbreeding all the way. The populations at the two ends of the range live in very different environments.

Seven monkeys escape from an enclosure. To everyone’s surprise, they establish a small but viable population, coexisting successfully with humans in a partly suburban environment very different from their native African habitat

Answer 84

Seven monkeys escape from an enclosure. To everyone’s surprise, they establish a small but viable population, coexisting successfully with humans in a partly suburban environment very different from their native African habitat

Question 85

A woman struggling with a bacterial illness is prescribed a month’s supply of a potent antibiotic. She takes the antibiotic for about two weeks and feels much better. Should she save the remaining two-week supply, or should she continue taking the drug?

Answer 85

She should continue taking the drug until her immune system can completely eliminate the infection. Otherwise, some bacteria may remain in her system, and they will probably be resistant.

Question 86

One of the key contributions of the punctuated equilibrium model is that it helps explain

Answer 86

why transitional fossils tend to be rare and certain common fossil species remain unchanged for long time spans.

Question 87

The fossil record shows that for many plant and animal groups, the time between speciation events

Answer 87

varies greatly, but averages 6.5 million years.

Question 88

The process through which species not closely related may come to resemble one another if they live in a similar environment is known as

Answer 88

convergent evolution.

Question 89

Under the biological species concept, a species is a group of organisms that

Answer 89

have the potential to interbreed in nature and produce fertile offspring.

Question 90

Darwin was the first person to draw an evolutionary tree, a diagram that represents

Answer 90

evidence-based hypotheses regarding our understanding of patterns of evolutionary descent.

Question 91

Allopatric speciation is not likely to occur when

Answer 91

there is no disruption in gene flow between two populations.

Question 92

Some of your DNA may not code for any protein and has no known function in gene regulation; it is sometimes referred to as noncoding DNA. How do nucleotide sequences of “noncoding DNA” evolve?

Answer 92

They evolve through genetic drift and other chance processes.

Question 93

Which of the following statements regarding the currently available fossil record is false?

Answer 93

The currently available fossil record shows that the first life-forms were eukaryotes.

Question 94

How is the merging of continents to form Pangaea believed to have altered Earth’s environments at the end of the Paleozoic era?

Answer 94

Shallow coastal areas were drained, leading to the extinction of many marine species.

Question 95

Which of the following statements regarding natural selection is false?

Natural selection depends on the local environment at the current time.

Natural selection starts with the creation of new alleles that are directed toward improving an organism’s fitness.

Natural selection and evolutionary change can occur in a short period of time (a few generations).

Natural selection can be observed working in organisms alive today.

Answer 95

Natural selection starts with the creation of new alleles that are directed toward improving an organism’s fitness.

Question 96

A population of butterflies has an allele B for big spots on the wings and b for small spots on the wings. The table below provides data about this population.

Genotype BB Bb bb
Number of butterflies 300 400 300
Genotype frequency 0.3 0.4 0.3

Regarding these data about the butterfly population, which of the following statements is correct?

The population is in Hardy-Weinberg equilibrium because the number of B alleles is equal to the number of b alleles.

The population is in Hardy-Weinberg equilibrium because half of the heterozygotes are B and half are b.

The population is not in Hardy-Weinberg equilibrium because p2 and 2pq are different.

The population is not in Hardy-Weinberg equilibrium because the genotype frequency of bb is greater than it would be in equilibrium.

Answer 96

The population is not in Hardy-Weinberg equilibrium because the genotype frequency of bb is greater than it would be in equilibrium.

Question 97

Anti-evolutionary thinkers sometimes argue that natural selection could not produce a complex structure like the vertebrate eye. They claim that all of the parts of the eye must have arisen at once, asking why natural selection would favor the development of part of an eye that is not yet capable of forming a focused image. Which of the statements about the molluscan eye rejects the claim of anti-evolutionary thinkers?

Answer 97

There are many intermediate stages of eye complexity, such as those in molluscs, that fulfill different adaptive functions.

Question 98

Speciation often occurs when a habitat becomes more heterogeneous. In Lake Victoria different species of cichlids are found in different areas of the lake. The best explanation for this speciation is that

Answer 98

natural selection favored different heritable variations in different parts of the lake.

Question 99

Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to

Answer 99

maintain two phenotypes in a dynamic equilibrium in a population.

Question 100

One of the finest available sequences of fossils shows how horses have changed slowly and by subtle steps from small, shrub-browsing ancestors to the large, grass-grazing modern horse. A large number of fossil species have been named, and it is often difficult to decide on the identity of a fossil horse because transitional forms are common. This record of evolution best fits the idea of

Answer 100

the gradual model of speciation.

Question 101

The technique called radiometric dating is based on

Answer 101

the steady, clocklike decay of certain radioactive isotopes over time.

Question 102

When a tetraploid flower pollinates a diploid flower of the parental species, the resulting offspring will be

Answer 102

triploid and sterile.

Question 103

Which of the following assumptions or observations is not part of Darwin’s idea of natural selection?

Answer 103

Whether an organism survives and reproduces is almost entirely a matter of random chance.

Question 104

Mate-attracting features such as the bright plumage of a male peacock result from

Answer 104

intersexual selection.

Question 105

Two populations of organisms belong to the same biological species when they

Answer 105

encounter each other, mate, and produce viable, fertile offspring under natural conditions.

Question 106

Aristotle believed that

Answer 106

species are fixed (permanent) and perfect.

Question 107

The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn’t natural selection eliminate this allele from all human populations?

Answer 107

In populations where endemic malaria is present, heterozygotes have an important advantage: They are resistant to malaria and therefore are more likely to survive and produce offspring that carry the allele.

Question 108

The Himalayas are an example of a mountain range that formed as a result of

Answer 108

the collision of two continental plates.

Question 109

Under the biological species concept, a species is a group of organisms that

Answer 109

have the potential to interbreed in nature and produce fertile offspring.

Question 110

The example of ocean and lake stickleback fishes indicates that morphology can be altered by

Answer 110

altering the expression of a gene that is associated with development in only some parts of the body.

Question 111

In a population of plants with a diploid number of 12, a new individual appeared with a chromosome number of 24. If this organism could self-fertilize, forming offspring with the same number of chromosomes (24), scientists would consider this an example of

Answer 111

sympatric speciation.

Question 112

A group of dog breeders is trying to design and develop an ideal dog. They want a dog with a gentle disposition, black fur, long ears, short legs, and a strong sense of smell. Which of the following comments from fellow dog breeders represents the biggest challenge they are likely to face?

Answer 112

There does not seem to be any genetic variation in sense of smell.

Question 113

How is the merging of continents to form Pangaea believed to have altered Earth’s environments at the end of the Paleozoic era?

Answer 113

Shallow coastal areas were drained, leading to the extinction of many marine species.

Question 114

Earth’s continents and seafloors together form a thin outer layer of the planet called the

Answer 114

crust.

Question 115

Speciation, or the formation of new species, is

Answer 115

responsible for the diversity of life.

Question 116

Which of the following would prevent an organism from becoming part of the fossil record when it dies?

Answer 116

It is fully decomposed by bacteria and fungi.

Question 117

In populations of the greater prairie chicken in Illinois, genetic diversity was lost through

Answer 117

genetic drift and restored by gene flow.

Question 118

The similarities in function of hummingbird wings and the wings of a butterfly reflect

Answer 118

analogy but not homology.

Question 119

How can the success of one group of organisms promote the adaptive radiation of a second group?

Answer 119

by providing new food resources, habitats, etc. for the second group to utilize

Question 120

The Mesozoic era is often called the age of reptiles. Which of the following also occurred during this era?

Answer 120

the appearance of the first mammals and flowering plants on land

Question 121

how does microevolution differ from speciation?

Answer 121

Microevolution involves evolutionary changes within a population; speciation occurs when a population changes enough that it diverges from its parent species and becomes a new species.

Question 122

What is the idea that living species are descendants of ancestral species that were different from present day ones?

Answer 122

Theory of evolution

Question 123

____explains the diversity of life

Answer 123

evolution

Question 124

Many of darwins obsevations indicated that _______ is a better predictor of relationships among orgs than similiarity in environment

Answer 124

georgraphic proximity

Question 125

What was darwins phrase for evolution?

Answer 125

descent with modification,”

Question 126

What is the theory of natural selection

Answer 126

individuals with certain traits are more likely to survive and reproduce than are individuals who do not have those traits.

Question 127

the idea that living species are descendants of ancestral species that were different from present-day ones.

Answer 127

evolution

Question 128

New layers of sediment cover older ones and compress them into layers of rock called

Answer 128

strata

Question 129

the chronicle of evolution over millions of years of geologic time engraved in the order in which fossils appear in rock strata—

Answer 129

the fossil record

Question 130

Similarity resulting from common ancestry is known as

Answer 130

homology

Question 131

features that often have different functions but are structurally similar because of common ancestry.

the arms, forelegs, flippers, and wings of different mammals

Answer 131

homologous structures

Question 132

Some of the most interesting homologies are “leftover” structures that are of marginal or perhaps no importance to the organism. These ________ are remnants of features that served important functions in the organism’s ancestors

Answer 132

vestigial structures

Question 133

In this diagram, each branch point represents the common ancestor of all species that descended from it

Answer 133

evolutionary tree

Question 134

e selective breeding of domesticated plants and animals to promote the occurrence of desirable traits in the offspring—

Answer 134

artificial selection—

Question 135

artificial selection has two essential components, what are they

Answer 135

variation and heritability.

Question 136

allows the breeder to select the animals or plants with the most desirable combination of characters as breeding stock for the next generation

Answer 136

varition

Question 137

refers to the transmission of a trait from parent to offspring

Answer 137

Heritability

Question 138

Individuals whose traits better enable them to obtain food or escape predators or tolerate physical conditions will survive and reproduce more successfully, passing these adaptive traits to their offspring

Answer 138

The essence of natural selection

Question 139

responsible for the tremendous diversity of life on Earth, including the extraordinary variety of unique species on the Galápagos Islands.

Answer 139

speciation

Question 140

the role of natural selection in the gradual adaptation of a population to its environment. changes in the gene pool of a population from one generation to the next

Answer 140

microevolution

Question 141

he process by which one species splits into two or more species

Answer 141

speciation,

Question 142

how does microevolution differ from speciation?

Answer 142

Microevolution involves evolutionary changes within a population; speciation occurs when a population changes enough that it diverges from its parent species and becomes a new species.

Question 143

a group of populations whose members have the potential to interbreed in nature and produce fertile offspring (offspring that themselves can reproduce).

Answer 143

species a

Question 144

The existence of barriers that stop members of two species from producing viable, fertile offspring with each other is called

Answer 144

reproductive isolation.

Question 145

Many pairs of species are distinct and yet are capable of interbreeding. The offspring of pairs of clearly distinct species are called

Answer 145

hybrids.

Question 146

For most organisms—sexual, asexual, and fossils alike—classification is based mainly on physical traits such as shape, size, and other features of (form)

Answer 146

morphological species concept

Question 147

dentifies species in terms of their ecological niches, focusing on unique adaptations to particular roles in a biological community.

Answer 147

ecological species concept,

Question 148

efines a species as the smallest group of individuals that share a common ancestor and thus form one branch on the tree of life

Answer 148

phylogenetic species concept

Question 149

The various types of reproductive barriers that isolate the gene pools of species can be categorized as either

Answer 149

prezygotic or postzygotic,

Question 150

_____ barriers prevent mating or fertilization between species

Answer 150

Prezygotic

Question 151

____ barriers operate after hybrid zygotes have formed.

Answer 151

Postzygotic

Question 152

Haitat, temporal, behavioral, gametic, and mechanical are all types of ____ barriers

Answer 152

Prezygotic

Question 153

A key event in the origin of a new species is the interruption of ____ between populations of the same species.

Answer 153

gene flow

Question 154

In _______ speciation a population is divided into geographically isolated subpopulations. With its gene pool isolated, a splinter population can follow its own evolutionary course.

Answer 154

n allopatric speciation

Question 155

Geographic isolation creates opportunities for speciation, but it does not necessarily lead to new species. speciation occurs only when the gene pool undergoes changes that establish reproductive barriers. what might cause such barriers to arise?

Answer 155

The environment of an isolated population may include different food sources, different types of pollinators, and different predators.

Question 156

in _____ speciation a new species arises within the same geographic area as its parent species

Answer 156

sympatric

Question 157

Polyploidy, habitat differentiation, and sexual selection are factors that can

Answer 157

reduce gene flow in sympatric populations.

Question 158

Many plant species have originated from sympatric speciation that occurs when accidents during cell division result in extra sets of _________. new species formed in this way are _____, meaning that their cells have more than two complete sets of chromosomes

Answer 158

chromosomes…. polyploid

Question 159

____ is a form of natural selection in which individuals with certain traits are more likely to obtain mates. it can interrupt gene flow within a population and may therefore be an important factor in sympatric speciation.

Answer 159

sexual selection

Question 160

The evolution of many diverse species from a common ancestor is known as… period of ev. change in which groups of orgs form many new species whose adaptations allow them to fill new or vacant ecologocial roles in their communites

Answer 160

adaptive radiation.

Question 161

regions in which members of different species meet and mate, producing at least some hybrid offspring.

Answer 161

hybrid zones

Question 162

reproductive barriers are _____ when populations of these two species overlap.

Answer 162

reinforced

Question 163

What happens when the reproductive barriers between species are weak and the species come into contact in a hybrid zone?

Answer 163

so much gene flow may occur that the speciation process reverses, causing the two hybridizing species to fuse into one.

Question 164

producing many viable hybrid offspring, and the once isolated gene pools of the parent species are combining—two species fusing into a single hybrid specie

Answer 164

interbreeding

Question 165

many hybrid zones are fairly _____and hybrids continue to be produced. Although these hybrids allow for some gene flow between populations, each species maintains its own integrity.

Answer 165

stable

Question 166

long periods of little apparent morphological change (equilibria) interrupted (punctuated) by relatively brief periods of sudden change

Answer 166

punctuated equilibria

Question 167

The origin of birds from a lineage of reptiles is an example of ________ evolutionary change above the species level

Answer 167

macroevolution

Question 168

earth formed about ____ years ago from a vast swirling cloud of dust that surrounded the young sun.

Answer 168

4.6 billin

Question 169

layered rock that results from the activites of prokaryotes that bind thin films of sediment together

Answer 169

stromatolite

Question 170

all life arises only by the reproduction of preexisting ____

Answer 170

life

Question 171

Why do 3.5-billion-year-old stromatolites suggest that life originated before 3.5 billion years ago?

Answer 171

If photosynthetic prokaryotes existed by 3.5 billion years ago, a simpler, nonphotosynthetic cell probably originated well before that time

Question 172

Miller identified a variety of organic molecules that are common in organisms, and some of the amino acids that make up proteins. His results—the first evidence that the molecules of life could have arisen spontaneously from _______ ________

Answer 172

inorganic precursors

Question 173

What are the 4 eons of earths history?

Answer 173

The Hadean, Archaean, Proterozoic , Phanerozoic.

Question 174

how long ago did oxygen begin to appear in the atomosphere

Answer 174

2.7 bill ion yrs ago

Question 175

The most widespread and diverse land animals are ______(particularly insects and ______ spiders) and(vertebrates with four appendages).

Answer 175

arthropods, tetrapods

Question 176

What is the order of earth periods? big to small

Answer 176

Eons, Era, Period

Question 177

What are the 3 eras the phanerozoiz eon is divided into

Answer 177

Paleozoic, Mesozoic, and Cenozoic

Question 178

As mentioned earlier, the oldest-known fossils, dating from ____years ago, are of _____

Answer 178

3.5 bill, prokaryotes

Question 179

he oldest fossils of _____ cells are from _____years ago

Answer 179

eukaryotic , 1.8 bill

Question 180

during the early ___ virtually all life was aquatic,

Answer 180

Paleozoic,

Question 181

The ___ (“middle animal”) era is also known as the age of reptiles because of its abundance of reptilian fossils, including those of the dinosaurs

Answer 181

Mesozoic

Question 182

An explosive period of evolution of mammals, birds, insects, and angiosperms began at the dawn of the _____(“recent animal”) era, about 66 million years ag

Answer 182

Cenozoic

Question 183

since the origin of multicellular eukaryotes there have been ____occasions—in which the landmasses of Earth came together to form a supercontinent, and later broke apart

Answer 183

3

Question 184

The continents and seafloors form a thin outer layer of planet Earth, called the _____ which covers a mass of hot, viscous material called the _____

Answer 184

crust, mantle

Question 185

according to the theory of ____ ______ Earth’s crust is divided into giant, irregularly shaped plates) that essentially float on the underlying mantle

Answer 185

plate tectonics

Question 186

two plates are sliding past each other, forming regions where ____ are common.

Answer 186

eathquake

Question 187

two plates are colliding. Massive upheavals may occur, forming ____ along the plate boundaries.

Answer 187

mountains

Question 188

During the ____ era, Pangaea started to break apart, causing a geographic isolation of colossal proportions

Answer 188

Mesozoic

Question 189

grind together and gradually slide past each other in what geologists call a ____ fault

Answer 189

strike slip

Question 190

____are often found where tectonic plates are diverging or converging, as opposed to sliding past each other.

Answer 190

volcanoes

Question 191

____ can cause the collapse of an ecological community by disrupting the complex web of relationships that form its infrastructure. And once an evolutionary lineage disappears, it cannot reappear.

Answer 191

mass extinston

Question 192

___ are studying how slight genetic changes can become magnified into major morphological differences between species

Answer 192

“evo-devo”— scientist

Question 193

e retention in the adult body of structures that were juvenile features in an ancestral species.

Answer 193

paedomorphosis

Question 194

____ genes, the master control genes, determine such basic features as where a pair of wing

Answer 194

Homeotic

Question 195

structures that evolve in one context but become co-opted for another function are called _____

Answer 195

exaptations.

Question 196

the branch of biology concerned with identifying, naming, and classifying species

Answer 196

taxonomy

Question 197

order if classicication of orgs

Answer 197

domains-kingdom-phyla-classes-orders-family-genus-species

Question 198

biologists traditionally use ____ trees to depict hypotheses about the evolutionary history of species. T

Answer 198

phylogenetic

Question 199

hen similar environments and natural selection produce similar adaptations in organisms from different evolutionary lineages.

Answer 199

Convergent evolution

Question 200

similarity due to convergent evolution is called

Answer 200

analogy.

Question 201

new alleles originate by _____ a change in the genetic info encoded in the nucleotide sequcne of dna

Answer 201

mutation

Question 202

_____ is the ultimate source of the genetic variation that serves as raw material for evolution. In multicellular organisms, however, only _____ in cells that produce gametes can be passed to offspring and affect a population’s genetic variability.

Answer 202

mutation, mutations

Question 203

a group of individuals of the same species that live in the same area and can potentially interbreed.

Answer 203

population

Question 204

consists of all copies of every type of allele at every locus in all members of the population

Answer 204

gene pool

Question 205

When the relative frequencies of alleles in a population change like this over a number of generations, evolution is occurring on its smallest scale. Such a change in a gene pool is often called _______

Answer 205

microevolution.

Question 206

he three main causes of evolutionary change are

Answer 206

natural selection, genetic drift, and gene flow.

Question 207

chance events can cause allele frequencies to fluctuate unpredictably from one generation to the next. what is this process called? the smaller the pop, the more impact this will have

Answer 207

genetic drift

Question 208

Catastrophes such as hurricanes, floods, or fires may kill large numbers of individuals, leaving a small surviving population that is unlikely to have the same genetic makeup as the original population.. Such a drastic reduction in population size is called

Answer 208

bottleneck effect.

Question 209

Allele frequencies in a population can also change as a result of ______ by which a population may gain or lose alleles when fertile individuals move into or out of a population or when gametes (such as plant pollen) are transferred between population

Answer 209

gene flow

Question 210

mutation and sex reproduction are random but nat sel is not. T/F

Answer 210

True

Question 211

the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals.

Answer 211

relative fitness:

Question 212

_____selection shifts the overall makeup of the pop by acting against indiviudals at one of the phenotype extrems

Answer 212

directional selection

Question 213

_________selection favors intermediate phenotypes and acts against the extrems

Answer 213

stabilizing selection

Question 214

_____occurs when environmental conditions vary in a way that favors individuals at both ends of a phenotypic range over individuals with intermediate phentopyes

Answer 214

disruptive selection

Question 215

form of natural selection in which individuals with certain traits are more likely than other individuals to obtain mates

Answer 215

sexual selection

Question 216

distinction in appearance, called__________ is often manifested in a size difference, but it can also include forms of adornment, such as manes on lions

Answer 216

sexual dimorphism,

Question 217

n some species, individuals compete directly with members of the same sex for mates. this type of sexual selection is called _____ selection

Answer 217

intrasexual

Question 218

In a more common type of sexual selection, called______ selection (between sexes) or mate choice, individuals of one sex (usually females) are choosy in selecting their mates. Males with the largest or most colorful adornments are often the most attractive to females

Answer 218

intersexual

Question 219

In a ______, a recessive allele is, in effect, protected from natural selection.

Answer 219

heterozygote

Question 220

type of balancing selection in which heterozygous individuals have greater reproductive success than either type of homozygote, with the result that two or more alleles for a gene are maintained in the population

Answer 220

Heterozygote advantage

Question 221

natural selection acts on the phenotype, and recessive alleles only influence the phenotype of a______ ______ individual.

Answer 221

homozygous recessive

Question 222

a reproductive barrier that impedes mating between species or hinders fertilization if mating between 2 species is attempted. includes temporal, habitat, mechanical, behavioral, and gametic isolation

Answer 222

prezyotic barrier

Question 223

prevents hybrid zygotes produced by 2 different species from developing into viable fertile adults. includes reduced hybrid viability., reduced hybrid fertility, and hybrid breakdown.

Answer 223

postzygotic barier

Question 224

reduced hybrid viability is when the

Answer 224

the hybrid embryo dies.

Question 225

reduced hybrid fertility is when

Answer 225

the offspring is healthy but usually sterile.