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Which of the following statements describe what all members of a population share?. They are temporally isolated from each other. They are geographically isolated from each other. They are members of the same species. They have identical genes.
In a population of finches in which one group of birds has a short, parrotlike beak and another group has a long, narrow beak, what process has probably occurred?
If a mutation introduces a new skin color in a lizard population, which factor might determine whether the frequency of the new allele will increase?
What situation might develop in a population having some plants whose flowers open at midday and other plants whose flowers open late in the day?
Although they often live in the same habitat, the American toad breeds earlier in the spring than the Fowler’s toad does. What can be inferred from this information?
In a gene pool, as the relative frequency of one allele for a trait increases, the relative frequencies of other alleles for that trait decrease. _________________________
Mutations do not always affect an organism’s genotype—its physical, behavioral, and biochemical characteristics. _________________________
In a population of snakes with a range of body lengths, if the longest individuals have the highest fitness, disruptive selection is likely to occur. _________________________
In a population of birds, if females prefer males with long tails, the population violates the condition of directional selection described by the Hardy-Weinberg principle. _________________________
In the type of reproductive isolation called behavioral isolation, two populations are separated by barriers such as rivers or mountains. _________________________
Two populations that have overlapping ranges can remain reproductively isolated through behavioral isolation or temporal isolation from each other. _________________________
The first step of the speciation of the Galápagos finches likely was the arrival of founders from South America. _________________________
Most inherited differences in the appearances of two brothers are due to the _________________________ that occurred during the production of gametes in their parents.
The pattern of natural selection that acts most strongly against gray individuals in a population that ranges from black through gray to white is ____________________ selection.
When the phenotypes of polygenic traits are represented by a bell curve, the ____________________ of individuals close together on the curve is not very different.
In genetic drift, ____________________, not natural selection, plays a primary role in determining the number of descendants an organism has.
According to the _________________________ principle, allele frequencies in a population will remain constant unless one or more of five specific factors cause those frequencies to change.
If two populations have been reproductively isolated and can no longer breed and produce fertile offspring, the process of _________________________ has occurred.
In the Galápagos finches that Rosemary and Peter Grant studied, a pattern of natural selection called ____________________ selection favored individuals with larger, heavier beaks during a drought.
In a particular environment, populations that are very different from each other are less likely to ____________________ with each other for resources.
What does a bell-shaped curve showing the phenotypes for human height indicate about the relative number of very short and very tall people?
How does the size of a population affect the likelihood that its genetic crosses will produce the ratio of alleles predicted by the laws of probability?
Which population, one of nearly identical organisms or one of phenotypically varied organisms, would be more likely to remain in genetic equilibrium?
What are three mechanisms for reproductive isolation? Which mechanism isolates two populations of similar frogs with different mating calls?
For a trait that has many different alleles, would an individual in the population be more likely to have that allele if it has a low relative frequency or a high relative frequency? Why?
If the relative frequency of a single allele for a particular trait declines over time, what would happen to the relative frequencies of some or all other alleles for that trait? Explain
Explain how shuffling a deck of playing cards can be a good model for the effect of sexual reproduction on the relative frequency of alleles in a population and the possible combinations of alleles.
Define mutation and describe one situation in which a point mutation—the alteration of a single nucleotide—would affect an organism’s phenotype and another situation in which a point mutation would not affect phenotype.
For a population, are the frequencies of phenotypes for a single-gene trait best expressed by a bar graph or a curve? Are the frequencies of phenotypes for a polygenic trait best expressed by a bar graph or a curve? Explain
The Hardy-Weinberg principle describes the conditions needed for the frequency of alleles in a population to remain unchanged. Explain why that stability occurs.
Assume that a geographic barrier that results in two very different ecosystems splits a single population. What would likely happen to the two separate populations? Would this process occur more quickly, less quickly, or at the same rate as it would if the two populations lived in similar ecosystems?
If each of the Galápagos Islands had contained an identical assortment and abundance of vegetation, would the impact of natural selection have been as pronounced as it was? Explain