Prior to 1800 in England, the typical moth of the species Biston betularia (peppered moth) had a light pattern. Dark colored moths were rare. By the late 19th century, the light-colored moths were rare, and the moths with dark patterns were abundant.
The cause of this change was hypothesized to be selective predation by birds (J.W. Tutt, 1896). During the industrial revolution, soot and other wastes from industrial processes killed tree lichens and darkened tree trunks. Thus, prior to the pollution of the industrial revolution, dark moths stood out on light-colored trees and were vulnerable to predators. With the rise of pollution, however, the coloring of moths vulnerable to predators changed to light.
Which of the following aspects of Darwin’s theory of evolution does the story of the peppered moth most clearly illustrate?
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There is competition for resources in an overbred population.
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There is great variability among members of a population.
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There is differential reproduction of individuals with favorable traits.
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The majority of characteristics of organisms are inherited.
Prior to 1800 in England, the typical moth of the species Biston betularia (peppered moth) had a light pattern. Dark colored moths were rare. By the late 19th century, the light-colored moths were rare, and the moths with dark patterns were abundant.
The cause of this change was hypothesized to be selective predation by birds (J.W. Tutt, 1896). During the industrial revolution, soot and other wastes from industrial processes killed tree lichens and darkened tree trunks. Thus, prior to the pollution of the industrial revolution, dark moths stood out on light-colored trees and were vulnerable to predators. With the rise of pollution, however, the coloring of moths vulnerable to predators changed to light.
In the late 1900s, England cleaned up its air, and pollution decreased. The bark of trees went from dark to light.
Which of the following outcomes to the populations of peppered moth would you expect given this environmental change?
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An increase in the number of dark moths and a decrease in the number of light moths
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an increase in the number of moths overall
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an approximately equal number of light moths and dark moths
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an increase in the number of light moths and a decrease in the number of dark moths
Prior to 1800 in England, the typical moth of the species Biston betularia (peppered moth) had a light pattern. Dark colored moths were rare. By the late 19th century, the light-colored moths were rare, and the moths with dark patterns were abundant.
The cause of this change was hypothesized to be selective predation by birds (J.W. Tutt, 1896). During the industrial revolution, soot and other wastes from industrial processes killed tree lichens and darkened tree trunks. Thus, prior to the pollution of the industrial revolution, dark moths stood out on light-colored trees and were vulnerable to predators. With the rise of pollution, however, the coloring of moths vulnerable to predators changed to light.
Commonly used in biology textbooks, the peppered moth is a classic example of evolutionary change in action. The example describes changes in a population’s allele frequencies-a small-scale change, evolutionarily speaking. The presence of both light and dark forms within the gene pool is demonstrated by the story, but the peppered moth stays a peppered moth.
Which scenario, if it were to occur, would be a model for large-scale evolutionary change?
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Conditions change such that the dark form of the moth is favored and the light form is diminished in the population due to predation. Conditions change again, the dark form is vulnerable, and the light form returns to prevalence.
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Conditions change such that the dark form of the moth is favored and the light form is eradicated in the population due to predation. Conditions change again, the dark form is vulnerable, and the dark form is eradicated due to predation.
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Conditions change such that dark form of the moth is favored and the light form is diminished in the population due to predation. Conditions change again, and both forms have equal prevalence.
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Conditions change such that dark form of the moth is favored and the light form is eradicated in the population due to predation. Conditions change again, the dark form is vulnerable. It develops an adaptation that shields it from predation.
The image compares the genes on human chromosome 7 with genes found on the mouse genome.
What is a conclusion we can draw from this comparison?
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All the genes in human chromosome 7 can be found in the mouse genome.
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Humans and mice share some genes.
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Human chromosome 7 and mouse chromosome 7 are homologous.
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The human genome is larger than the mouse genome.
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Geologists provide evidence that earthquakes reshape life by causing mass extinctions.
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Botanists provide evidence that South American temperate plants have more in common with South American tropical plants than temperate plants from Europe.
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Zoologists provide evidence that fewer animal species live on islands than on nearby mainlands.
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Ecologists provide evidence that species diversity increases closer to the equator.
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Modern species are distinct natural entities.
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Modern species are not currently evolving.
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Modern species share a common ancestor.
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Modern species have both convergent and divergent traits.
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Some genes from the bacterium E. coli have sequences that are similar to genes found in humans.
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Marsupial mammals live in just a few places in the world today-Australia, South America, and part of North America.
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The fossil record shows that Rodhocetus, an aquatic mammal related to whales, had a type of ankle bone that is otherwise unique to a group of land animals.
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In the 1940s, infections by the bacterium Staphylococcus aureus could be treated with penicillin; today populations exist that are completely resistant.
Humans have 46 chromosomes. Great apes, including orangutans, gorillas and chimpanzees have 48 chromosomes. The image compares the human chromosomes 1 to 4 with great ape chromosomes 1 to 5.
Make a hypothesıs based on this image.
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The common ancestor of great apes and humans had 46 chromosomes.
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The common ancestor of great apes and humans had 48 chromosomes.
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Of the three great apes, humans are most closely related to gorillas.
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Of the three great apes, humans are most closely related to orangutans.
The image shows the migration of marsupials.
Make a hypothesis based on this image.
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Antarctica has fossils of marsupials that are more similar to modern ones.
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Marsupials first evolved in Africa.
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The earliest marsupial fossils would be found in Australia.
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Modern marsupials exist in all continents.
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Changes in the genes that are important to embryonic development have been relatively minor because there are no selective pressures on an individual before it is born
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Changes in the genes that are important to embryonic development have been relatively minor because not much time has elapsed since the divergence of the various animal taxa.
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Changes in the genes that are important to embryonic development have been relatively minor because early embryos are very fragile and even small mutations can result in death
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Changes in the genes that are important to embryonic development have been relatively minor because mutational tweaking in the embryo has magnified consequences in the adult
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Cats and humans are more closely related to each other than either are to whales.
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The shape of the whale forelimb arose a result of disadvantageous mutations
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The whale flipper is an adaptive characteristic unique to its water environment.
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The whale flipper is a vestigial structure.
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broad because dinosaurs originated before the breakup of Pangaea
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broad because some dinosaurs could fly between continents
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narrow because they went extinct too quickly to disperse very far
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narrow because they lived so long ago that the fossils have mostly broken down or disappeared
The term microevolution describes evolution on its smallest scale: the change in allele frequencies in a population over generations. DDT is a pesticide that was widely in use in the United States from the 1940s until 1972. The table below summarizes a particular allele frequency in laboratory strains of the common fruit fly, Drosophila melanogaster
Strains collected from flies in the wild in the 1930s | Strains collected from flies in the wild in the 1960s | |
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Frequency of allele conferring DDT resistance | 0% | 40% |
Using this information, describe a model in which natural selection improved the match between D. mealanogaster and its environment through microevolution.
- DDT killed off a large proportion of the population, and the alleles present in the surviving fruit flies differed from those in the original population
- Mutations from the application of DDT caused the allele conferring DDT resistance to appear in the population.
- Female mosquitoes chose to mate with male mosquitoes that had the allele conferring DDT resistance because it would make their offspring more fit.
- The wide use of DDT meant that fruit flies with DDT resistance were more evolutionarily fit than their counterparts without DDT resistance.
The ulna and radius are two bones found in the forearms of most mammals. In some mammals, including humans, these bones allow rotation of the forearm. In some mammal species, the ulna has become vestigial. The images show the human arm bones and the skeletons of species where this bone has become vestigial. The first two animal images are from bats and the last animal image is from a bison. Ulna is shown with the label "u".
What is a conclusion we can draw from these images?
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In most mammals, the ulna is a vestigial structure.
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In bats and bison, forearm rotation is done by some other means.
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Mammals that walk, instead of fly, have a non-vestigial ulna.
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The mammals shown here and humans share a common ancestor which had an ulna.
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The resistant viruses passed their genes to the non-resistant viruses so that 100% of the viruses became resistant. This illustrates evolution as an ongoing process because the genes of the population changed in real time.
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The non-resistant viruses died, and the resistant ones survived and rapidly reproduced. This illustrates evolution as an ongoing process because the change in the HIV population is the result of natural selection.
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The viruses developed resistance to the drug after repeated exposure to it. This illustrates evolution as an ongoing process because the viruses were able to adapt to changing conditions.
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The drug-resistant viruses were more fit than their non-resistant counterparts to begin with, and over time they dominated the population. This illustrates evolution as an ongoing process because natural selection favored one phenotype over another.
A friend says: “Natural selection is about the survival of the very fittest in a population. The fittest are those that are strongest, largest, fastest.”
Would you agree with that statement? Explain. What evidence from scientific disciplines can you offer to support your agreement or your disagreement?
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The statement is true. If an organism is not strong and fast, it will not survive long enough to reproduce and pass on its genes, and if it is not large and fitter than the other individuals around it then it will not be able to compete for a mate. Many seal species, for example, have only a single male who gets to mate. He must be the very fittest seal to win all the females.
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The very fittest organisms are not necessarily the ones that survive. Sometimes it is the least fit organisms that survive and reproduce. For example, in one generation the mice who are bad at foraging for seeds may reproduce prolifically and dominate the mice who are good at foraging. In this case, natural selection will select for the less-fit phenotype and spread it in the population.
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The definition of fitness is not correct. The strongest and fastest organisms are more fit than the weaker and slower ones, but large individuals are often at a disadvantage to smaller ones because they are easily spotted by predators. For example, a large rabbit will stick out on a field more than a small one and will get eaten by a hawk.
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What is meant by “fittest” is not necessarily strong, large, and fast. Fitness, as defined in evolutionary terms, has to do with survival and the reproduction of genetic material. For example, a small but showy male bird may be selected by female birds to reproduce, while a large but less colorful one is not.
A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained:
Which of the following best supports the hypothesis that the difference in leaf color is genetically controlled?
- the number of yellow-leaved seedlings in dish A on day 7
- the number of germinated seeds in dish A on days 7 and 14
- the death of all the yellow-leaved seedings
- the existence of yellow-leaved seedlings as well as green-leaved ones on day 14 in dish B
Use the data from Figure 18.27 to answer the question. Which best describes the usefulness of the yellow-leaved phenotype as a variation subject to natural selection?
- the yellow-leaved phenotype can germinate in environments without light
- the germination of the yellow-leaved phenotype is unaffected by light intensity
- the germination of the yellow-leaved phenotype is accelerated as compared to the green-leaved phenotype
- the yellow-leaved phenotype cannot germinate in environments with light
Use the data from Figure 18.27 to answer the question. Yellow-leaved seedlings are unable to convert light energy to chemical energy. Which observation is most likely to be made on day 21?
- a few yellow-leaved seedlings alive in dish A, but none in dish B
- a few yellow-leaved seedlings alive in dish B, but none in dish A
- no yellow-leaved seedlings alive in dish A or dish B
- a few yellow-leaved seedlings alive in dish A and dish B
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The populations of toads on the other side of the banded territory are not completely nocturnal.
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Fertile hybrid populations of toads are found between the two other populations.
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There appear to be some hybrid toads between the two populations, but they are few and frail.
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The two populations of toads enact very different mating behaviors.
A group of students summarized information on five great extinction events. The students are sampling a site in search of fossils from the Devonian period. Based on the chart, what would be the most reasonable plan for the students to follow?
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searching horizontal rock layers in any class of rock and trying to find those that contain the greatest number of fossils
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collecting fossils from rock layers deposited prior to the Permian period that contain some early vertebrate bones
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looking in sedimentary layers next to bodies of water in order to find marine fossils of bivalves and trilobites
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using relative dating techniques to determine the geological ages of the fossils found so they can calculate the rate of speciation of early organisms
Populations of a plant species have been found growing in the mountains at altitudes above 2,500 meters. Populations of a plant that appears similar, with slight differences, have been found in the same mountains at altitudes below 2,300 meters.
Describe a plan for collecting two kinds of data that could provide a direct answer to the question: do the populations growing above 2,500 meters and the populations growing below 2,300 meters represent a single species?
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Scientists could take the genetic code of a plant from each altitude and determine whether the two sets of DNA are identical. They could also insert genes from one plant into the cells from the other and see if the cells survive
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Scientists could look in the fossil record to find the plants’ most recent common ancestor. They could also check the surrounding mountains to determine if the most recent common ancestor is still living.
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Scientists could breed the two groups in the same environment and observe whether, over several generations, they begin to look more similar. They could also switch the groups, growing the high-altitude plants at low altitude and the low-altitude plants at high altitude, and observe whether the former begin to look like low-altitude plants and the latter begin to look like high-altitude plants.
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Scientists could collect seeds and test whether they might be cross-pollinated to produce fertile offspring. They could also investigate the area between 2,500 meters and 2,300 meters to see if fertile hybrid populations might be found living between the two other populations of plants.
Populations of a plant species have been found growing in the mountains at altitudes above 2,500 meters. Populations of a plant that appears similar, with slight differences, have been found in the same mountains at altitudes below 2,300 meters.
How can you test if speciation has taken place?
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Test if the slight differences in phenotype are eliminated when the two plants are grown in the same environment.
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If the seeds from the plants can be cross fertilized and developed into fertile offspring, the two populations are not yet reproductively isolated and remain one species.
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If genes transplanted between the plants function successfully, then the plants must be similar enough to each other to belong to the same species.
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If scientists are able to find the common ancestor of the two groups in the fossil record or in neighboring communities, then they can determine whether the plants have diverged into separate species or remain a single species.
Assuming a population that has genetic variation and is under the influence of natural selection, place the following events in the order in which they would occur:
- Genetic frequencies within the population change.
- A change occurs in the population’s environment.
- Phenotypic variations shift.
- Individuals who are well-adapted leave more offspring than individuals who are poorly adapted.
- Individuals who are poorly adapted do not survive at the same rate as individuals who are well adapted.
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- A change occurs in the population’s environment.
- Individuals who are poorly adapted do not survive at the same rate as individuals who are well adapted.
- Individuals who are well-adapted leave more offspring than individuals who are poorly adapted.
- Genetic frequencies within the population change.
- Phenotypic variations shift.
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- A change occurs in the population’s environment.
- Genetic frequencies within the population change.
- Phenotypic variations shift.
- Individuals who are poorly adapted do not survive at the same rate as individuals who are well adapted.
- Individuals who are well-adapted leave more offspring than individuals who are poorly adapted.
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- Phenotypic variations shift.
- A change occurs in the population’s environment.
- Genetic frequencies within the population change.
- Individuals who are poorly adapted do not survive at the same rate as individuals who are well adapted.
- Individuals who are well-adapted leave more offspring than individuals who are poorly adapted.
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- Individuals who are well-adapted leave more offspring than individuals who are poorly adapted.
- Individuals who are poorly adapted do not survive at the same rate as individuals who are well adapted.
- Phenotypic variations shift.
- Genetic frequencies within the population change.
- A change occurs in the population’s environment.
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Either there was fewer food available or the degree of predation increased. The future generations of this group of voles should evidence fewer genetic variation.
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Either there was fewer food available or the degree of predation increased. The future generations of this group of voles should evidence greater genetic variation.
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Either there was more food available or the degree of predation decreased. The future generations of this group of voles should evidence less genetic variation.
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Either there was more food available or the degree of predation decreased. The future generations of this group of voles should evidence greater genetic variation.
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The birds with small, thin beaks will grow larger, broader beaks to be able to eat the larger seeds. This will result in subsequent generations having a higher percentage of birds with large, broad beaks.
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There will be more birds with small, thin beaks dying and more birds with large, broad beaks surviving. Differential reproduction of birds with large, broad beaks will result in subsequent generations having a higher percentage of birds with large, broad beaks.
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The species will diverge into two species, one with small, thin beaks and one with large, broad beaks. The two species will then compete for resources.
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There will be neither phenotypic nor genotypic changes in the population.
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The populations have become dependent on the island food sources.
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The populations have become morphologically distinct from the mainland species.
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The populations have become adapted to the island habitat.
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The populations have become reproductively isolated from the mainland species.
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In the case of gradual speciation, the fossil record would show only a few hybrid individuals, followed by individuals of the two distinct species. For the case of punctuated equilibrium, the fossil record would show many hybrid individuals persisting through several geological layers.
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In the case of gradual speciation, the fossil record would show the parent species in a single location, such that the newly diverged species remained in contact with each other. For the case of punctuated equilibrium, the fossil record would show a geographic divide within the parent species that caused it to diverge into multiple new species.
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In the case of gradual speciation, the fossil record would show many intermediate forms. For the case of punctuated equilibrium, the fossil record would show new forms that persist essentially unchanged through several geological layers, then disappear just as a new form appears.
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Gradual speciation would be undetectable in the fossil record. For the case of punctuated equilibrium, the fossil record would show a steady progression of distinct forms.
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divergent evolution
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sympatric speciation
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allopatric speciation
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variation
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Natural selection would cause prezygotic barriers to reproduction between the parent species to strengthen over time.
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The production of unfit hybrids would increase and the speciation process would complete.
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The extensive mating between the species would continue to produce large numbers of hybrids.
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The gene pools of the parent species would fuse over time, reversing the speciation process.