Unit 4 Quiz (combined) Flashcards
1
Q
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
A
a harmful allele in an asexual, haploid population
2
Q
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.
A
This situation is an example of heterozygote advantage if tuberculosis is present in a population.
3
Q
Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to
A
maintain two phenotypes in a dynamic equilibrium in a population.
4
Q
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.
A
The mountain ants could not mate with the valley ants.
5
Q
Genetic differences between populations tend to be reduced by
A
gene flow.
6
Q
Darwin found that many of the species on the Galápagos Islands
A
resembled species on the nearest mainland.
7
Q
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.
A
If the group’s ancestors could not move across the open ocean, it is very likely that they were present on the original landmass.
8
Q
Two populations that have been separated by a river are most likely to become separate species if
A
genes controlling molecules on the surface of the sperm that bind with egg receptors are different in the two populations.
9
Q
Two species that occasionally mate and produce zygotes, but that have incompatible genes that prevent the resulting embryo from developing, are affected by
A
reduced hybrid viability.
10
Q
Most polyploid species arise from
A
the hybridization of two parent species.
11
Q
Mass extinctions
A
remove well-adapted species and groups from the Earth, so that it may take millions of years for species diversity to recover.
12
Q
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.
A
behavioral; prezygotic
13
Q
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
A
a change in the gene pool of a population from one generation to the next
14
Q
In the chiclid populations in Lake Victoria, what trait in females acted as a selection factor on which males they mated with?
A
color vision
15
Q
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
A
the appearance of the first mammals and flowering plants on land
16
Q
The example of ocean and lake stickleback fishes indicates that morphology can be altered by
A
altering the expression of a gene that is associated with development in only some parts of the body.
17
Q
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?
A
Different adaptive trends will probably be favored in the new climatic environment.
18
Q
Structures that evolved from the same structure in a common ancestor are
A
homologous.
19
Q
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.
A
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.
20
Q
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?
A
Thomas Malthus
21
Q
Sympatric speciation commonly occurs through ________ in plants but is more likely to occur through ________ in animals.
A
polyploidy; habitat differentiation and sexual selection
22
Q
Mate-attracting features such as the bright plumage of a male peacock result from
A
intersexual selection.
23
Q
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.
A
The hurricane has caused a population bottleneck and a loss of genetic diversity.
24
Q
Scientists hypothesize that a major factor promoting the adaptive radiation of mammals was probably
A
the mass extinction of most dinosaurs.
25
Scientists evaluating the Cretaceous mass extinction have concluded that
an asteroid impact was probably the triggering event for the extinction.
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
hybrid breakdown.
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?
Directional selection favored plants with notched leaves.
28
What was the probable role of oxygen gas in the early stages of life's appearance on Earth?
Oxygen gas tends to disrupt organic molecules, so its absence promoted the formation and stability of complex organic molecules on the early Earth.
29
When plants undergo allopatric speciation, an initial reproductive barrier is often
pollinator choice.
30
The findings of Pasteur and others have established that
life does not arise from nonliving matter today, but in the conditions of early Earth, such an event could have occurred.
31
Geologists have evidence that over the past 1.5 billion years
Earth's landmasses have joined into a single continent and split back apart again on three occasions.
32
Large antlers in male elk, which are used for battles between males, are a good example of a trait favored by
intrasexual selection.
33
Speciation without geographic isolation is called ________ speciation.
sympatric
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?
gametic isolation
35
The emergence of many diverse species from a common ancestor is called
adaptive radiation.
36
Miller-type experiments have shown that
complex organic molecules can be produced by physical processes from inorganic components.
37
The emergence of many diverse species from a common ancestor is called
adaptive radiation.
38
Miller-type experiments have shown that
complex organic molecules can be produced by physical processes from inorganic components.
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?
behavioral isolation
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?
Different adaptive trends will probably be favored in the new climatic environment.
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?
behavioral isolation
42
How can the success of one group of organisms promote the adaptive radiation of a second group?
by providing new food resources, habitats, etc. for the second group to utilize
43
Microevolution, or evolution at its smallest scale, occurs when
a population's allele frequencies change over a span of generations.
44
Which of the following will tend to produce adaptive changes in populations?
natural selection
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
allopatric speciation.
46
A population is
a group of individuals of the same species that live in the same area and interbreed.
47
When plants undergo allopatric speciation, an initial reproductive barrier is often
pollinator choice.
48
The biological species concept is
sometimes difficult to put into practice even for present sexual organisms and useless for asexual organisms and fossils.
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.
Permian
50
A spot where two continental plates are sliding past one another may be prone to
earthquakes.
51
Darwin found that many of the species on the Galápagos Islands
resembled species on the nearest mainland.
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.
Permian
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.
Each island in the Galápagos chain has one and only one isolated, unique species of Darwin's finch.
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?
mechanical isolation
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
analogy.
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.
Speciation occurs regularly as a result of the accumulation of many small changes.
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?
The population is likely in Hardy-Weinberg equilibrium for that locus.
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?
Different adaptive trends will probably be favored in the new climatic environment.
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
paedomorphosis.
60
One of the strongest lines of evidence of a meteor or comet impact in the late Cretaceous is
a thin layer of iridium-enriched clay in late Cretaceous fossil strata.
61
The ________ suggests that speciation occurs in brief spurts.
punctuated equilibrium model
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?
Any butterfly allele that allowed milkweed toxin storage would be likely to persist because butterflies that had it were more likely to survive.
63
It is estimated that the modern continents began to take shape
66 million years ago.
64
One of the strongest lines of evidence of a meteor or comet impact in the late Cretaceous is
a thin layer of iridium-enriched clay in late Cretaceous fossil strata.
65
Organisms that possess more than two complete sets of chromosomes are said to be
polyploid.
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
homology.
67
What evidence is used to determine the branching sequence of an evolutionary tree?
anatomical or molecular homologous structures
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?
punctuated equilibrium
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
convergent evolution.
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?
first prokaryotes, photosynthesis, first eukaryotes, colonization of land by plants and fungi
71
Which highly reactive gas was probably absent from the Earth's primitive atmosphere?
oxygen
72
Most polyploid species arise from
the hybridization of two parent species.
73
Which of the following assumptions or observations is not part of Darwin's idea of natural selection?
Whether an organism survives and reproduces is almost entirely a matter of random chance.
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
the gradual model of speciation.
75
Plants and fungi first became established on land during the
Paleozoic
76
Which of the following represents a pair of homologous structures?
the wing of a bird and the front legs of a horse
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?
habitat isolation
78
Scientists hypothesize that a major factor promoting the adaptive radiation of mammals was probably
the mass extinction of most dinosaurs.
79
Which of the following would tend to promote adaptive radiation?
An organism colonizes an isolated area that is habitable but relatively devoid of life.
80
Genetic drift resulting from a disaster that drastically reduces population size is called
the bottleneck effect.
81
Which of the following statements regarding fins on fishes is true?
Fins are an adaptation that aid in swimming.
82
Geologists have evidence that over the past 1.5 billion years
Earth's landmasses have joined into a single continent and split back apart again on three occasions.
83
Blue-footed boobies have webbed feet and are comically clumsy when they walk on land. Evolutionary scientists view these feet as
the outcome of a trade-off: Webbed feet perform poorly on land but are very helpful in diving for food.
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
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
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?
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.
86
One of the key contributions of the punctuated equilibrium model is that it helps explain
why transitional fossils tend to be rare and certain common fossil species remain unchanged for long time spans.
87
The fossil record shows that for many plant and animal groups, the time between speciation events
varies greatly, but averages 6.5 million years.
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
convergent evolution.
89
Under the biological species concept, a species is a group of organisms that
have the potential to interbreed in nature and produce fertile offspring.
90
Darwin was the first person to draw an evolutionary tree, a diagram that represents
evidence-based hypotheses regarding our understanding of patterns of evolutionary descent.
91
Allopatric speciation is not likely to occur when
there is no disruption in gene flow between two populations.
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?
They evolve through genetic drift and other chance processes.
93
Which of the following statements regarding the currently available fossil record is false?
The currently available fossil record shows that the first life-forms were eukaryotes.
94
How is the merging of continents to form Pangaea believed to have altered Earth's environments at the end of the Paleozoic era?
Shallow coastal areas were drained, leading to the extinction of many marine species.
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.
Natural selection starts with the creation of new alleles that are directed toward improving an organism's fitness.
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.
The population is not in Hardy-Weinberg equilibrium because the genotype frequency of bb is greater than it would be in equilibrium.
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?
There are many intermediate stages of eye complexity, such as those in molluscs, that fulfill different adaptive functions.
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
natural selection favored different heritable variations in different parts of the lake.
99
Frequency-dependent selection, as seen in the case of the scale-eating fish in Lake Tanganyika, tends to
maintain two phenotypes in a dynamic equilibrium in a population.
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
the gradual model of speciation.
101
The technique called radiometric dating is based on
the steady, clocklike decay of certain radioactive isotopes over time.
102
When a tetraploid flower pollinates a diploid flower of the parental species, the resulting offspring will be
triploid and sterile.
103
Which of the following assumptions or observations is not part of Darwin's idea of natural selection?
Whether an organism survives and reproduces is almost entirely a matter of random chance.
104
Mate-attracting features such as the bright plumage of a male peacock result from
intersexual selection.
105
Two populations of organisms belong to the same biological species when they
encounter each other, mate, and produce viable, fertile offspring under natural conditions.
106
Aristotle believed that
species are fixed (permanent) and perfect.
107
The sickle-cell allele produces a serious blood disease in homozygotes. Why doesn't natural selection eliminate this allele from all human populations?
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.
108
The Himalayas are an example of a mountain range that formed as a result of
the collision of two continental plates.
109
Under the biological species concept, a species is a group of organisms that
have the potential to interbreed in nature and produce fertile offspring.
110
The example of ocean and lake stickleback fishes indicates that morphology can be altered by
altering the expression of a gene that is associated with development in only some parts of the body.
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
sympatric speciation.
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?
There does not seem to be any genetic variation in sense of smell.
113
How is the merging of continents to form Pangaea believed to have altered Earth's environments at the end of the Paleozoic era?
Shallow coastal areas were drained, leading to the extinction of many marine species.
114
Earth's continents and seafloors together form a thin outer layer of the planet called the
crust.
115
Speciation, or the formation of new species, is
responsible for the diversity of life.
116
Which of the following would prevent an organism from becoming part of the fossil record when it dies?
It is fully decomposed by bacteria and fungi.
117
In populations of the greater prairie chicken in Illinois, genetic diversity was lost through
genetic drift and restored by gene flow.
118
The similarities in function of hummingbird wings and the wings of a butterfly reflect
analogy but not homology.
119
How can the success of one group of organisms promote the adaptive radiation of a second group?
by providing new food resources, habitats, etc. for the second group to utilize
120
The Mesozoic era is often called the age of reptiles. Which of the following also occurred during this era?
the appearance of the first mammals and flowering plants on land
121
how does microevolution differ from speciation?
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.
122
What is the idea that living species are descendants of ancestral species that were different from present day ones?
Theory of evolution
123
____explains the diversity of life
evolution
124
Many of darwins obsevations indicated that _______ is a better predictor of relationships among orgs than similiarity in environment
georgraphic proximity
125
What was darwins phrase for evolution?
descent with modification,”
126
What is the theory of natural selection
individuals with certain traits are more likely to survive and reproduce than are individuals who do not have those traits.
127
the idea that living species are descendants of ancestral species that were different from present-day ones.
evolution
128
New layers of sediment cover older ones and compress them into layers of rock called
strata
129
the chronicle of evolution over millions of years of geologic time engraved in the order in which fossils appear in rock strata—
the fossil record
130
Similarity resulting from common ancestry is known as
homology
131
features that often have different functions but are structurally similar because of common ancestry.
the arms, forelegs, flippers, and wings of different mammals
homologous structures
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
vestigial structures
133
In this diagram, each branch point represents the common ancestor of all species that descended from it
evolutionary tree
134
e selective breeding of domesticated plants and animals to promote the occurrence of desirable traits in the offspring—
artificial selection—
135
artificial selection has two essential components, what are they
variation and heritability.
136
allows the breeder to select the animals or plants with the most desirable combination of characters as breeding stock for the next generation
varition
137
refers to the transmission of a trait from parent to offspring
Heritability
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
The essence of natural selection
139
responsible for the tremendous diversity of life on Earth, including the extraordinary variety of unique species on the Galápagos Islands.
speciation
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
microevolution
141
he process by which one species splits into two or more species
speciation,
142
how does microevolution differ from speciation?
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.
143
a group of populations whose members have the potential to interbreed in nature and produce fertile offspring (offspring that themselves can reproduce).
species a
144
The existence of barriers that stop members of two species from producing viable, fertile offspring with each other is called
reproductive isolation.
145
Many pairs of species are distinct and yet are capable of interbreeding. The offspring of pairs of clearly distinct species are called
hybrids.
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)
morphological species concept
147
dentifies species in terms of their ecological niches, focusing on unique adaptations to particular roles in a biological community.
ecological species concept,
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
phylogenetic species concept
149
The various types of reproductive barriers that isolate the gene pools of species can be categorized as either
prezygotic or postzygotic,
150
_____ barriers prevent mating or fertilization between species
Prezygotic
151
____ barriers operate after hybrid zygotes have formed.
Postzygotic
152
Haitat, temporal, behavioral, gametic, and mechanical are all types of ____ barriers
Prezygotic
153
A key event in the origin of a new species is the interruption of ____ between populations of the same species.
gene flow
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.
n allopatric speciation
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?
The environment of an isolated population may include different food sources, different types of pollinators, and different predators.
156
in _____ speciation a new species arises within the same geographic area as its parent species
sympatric
157
Polyploidy, habitat differentiation, and sexual selection are factors that can
reduce gene flow in sympatric populations.
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
chromosomes.... polyploid
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.
sexual selection
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
adaptive radiation.
161
regions in which members of different species meet and mate, producing at least some hybrid offspring.
hybrid zones
162
reproductive barriers are _____ when populations of these two species overlap.
reinforced
163
What happens when the reproductive barriers between species are weak and the species come into contact in a hybrid zone?
so much gene flow may occur that the speciation process reverses, causing the two hybridizing species to fuse into one.
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
interbreeding
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.
stable
166
long periods of little apparent morphological change (equilibria) interrupted (punctuated) by relatively brief periods of sudden change
punctuated equilibria
167
The origin of birds from a lineage of reptiles is an example of ________ evolutionary change above the species level
macroevolution
168
earth formed about ____ years ago from a vast swirling cloud of dust that surrounded the young sun.
4.6 billin
169
layered rock that results from the activites of prokaryotes that bind thin films of sediment together
stromatolite
170
all life arises only by the reproduction of preexisting ____
life
171
Why do 3.5-billion-year-old stromatolites suggest that life originated before 3.5 billion years ago?
If photosynthetic prokaryotes existed by 3.5 billion years ago, a simpler, nonphotosynthetic cell probably originated well before that time
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 _______ ________
inorganic precursors
173
What are the 4 eons of earths history?
The Hadean, Archaean, Proterozoic , Phanerozoic.
174
how long ago did oxygen begin to appear in the atomosphere
2.7 bill ion yrs ago
175
The most widespread and diverse land animals are ______(particularly insects and ______ spiders) and(vertebrates with four appendages).
arthropods, tetrapods
176
What is the order of earth periods? big to small
Eons, Era, Period
177
What are the 3 eras the phanerozoiz eon is divided into
Paleozoic, Mesozoic, and Cenozoic
178
As mentioned earlier, the oldest-known fossils, dating from ____years ago, are of _____
3.5 bill, prokaryotes
179
he oldest fossils of _____ cells are from _____years ago
eukaryotic , 1.8 bill
180
during the early ___ virtually all life was aquatic,
Paleozoic,
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
Mesozoic
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
Cenozoic
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
3
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 _____
crust, mantle
185
according to the theory of ____ ______ Earth’s crust is divided into giant, irregularly shaped plates) that essentially float on the underlying mantle
plate tectonics
186
two plates are sliding past each other, forming regions where ____ are common.
eathquake
187
two plates are colliding. Massive upheavals may occur, forming ____ along the plate boundaries.
mountains
188
During the ____ era, Pangaea started to break apart, causing a geographic isolation of colossal proportions
Mesozoic
189
grind together and gradually slide past each other in what geologists call a ____ fault
strike slip
190
____are often found where tectonic plates are diverging or converging, as opposed to sliding past each other.
volcanoes
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.
mass extinston
192
___ are studying how slight genetic changes can become magnified into major morphological differences between species
“evo-devo”— scientist
193
e retention in the adult body of structures that were juvenile features in an ancestral species.
paedomorphosis
194
____ genes, the master control genes, determine such basic features as where a pair of wing
Homeotic
195
structures that evolve in one context but become co-opted for another function are called _____
exaptations.
196
the branch of biology concerned with identifying, naming, and classifying species
taxonomy
197
order if classicication of orgs
domains-kingdom-phyla-classes-orders-family-genus-species
198
biologists traditionally use ____ trees to depict hypotheses about the evolutionary history of species. T
phylogenetic
199
hen similar environments and natural selection produce similar adaptations in organisms from different evolutionary lineages.
Convergent evolution
200
similarity due to convergent evolution is called
analogy.
201
new alleles originate by _____ a change in the genetic info encoded in the nucleotide sequcne of dna
mutation
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.
mutation, mutations
203
a group of individuals of the same species that live in the same area and can potentially interbreed.
population
204
consists of all copies of every type of allele at every locus in all members of the population
gene pool
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 _______
microevolution.
206
he three main causes of evolutionary change are
natural selection, genetic drift, and gene flow.
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
genetic drift
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
bottleneck effect.
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
gene flow
210
mutation and sex reproduction are random but nat sel is not. T/F
True
211
the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals.
relative fitness:
212
_____selection shifts the overall makeup of the pop by acting against indiviudals at one of the phenotype extrems
directional selection
213
_________selection favors intermediate phenotypes and acts against the extrems
stabilizing selection
214
_____occurs when environmental conditions vary in a way that favors individuals at both ends of a phenotypic range over individuals with intermediate phentopyes
disruptive selection
215
form of natural selection in which individuals with certain traits are more likely than other individuals to obtain mates
sexual selection
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
sexual dimorphism,
217
n some species, individuals compete directly with members of the same sex for mates. this type of sexual selection is called _____ selection
intrasexual
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
intersexual
219
In a ______, a recessive allele is, in effect, protected from natural selection.
heterozygote
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
Heterozygote advantage
221
natural selection acts on the phenotype, and recessive alleles only influence the phenotype of a______ ______ individual.
homozygous recessive
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
prezyotic barrier
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.
postzygotic barier
224
reduced hybrid viability is when the
the hybrid embryo dies.
225
reduced hybrid fertility is when
the offspring is healthy but usually sterile.
