Exam 22: Speciation

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

Before transferring sperm to the female during mating, the males of some species of beetles use their copulatory organs to remove the sperm of other males.In cases in which a female mated first with a male of a different species, the male of her own species is particularly adept at removing the other male's sperm.This is an example of _______ isolation.

Evolutionary radiation

Which of the following does not appear to result in increased speciation rates?

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

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

In the eastern United States, populations of the white-footed mouse, Peromyscus leucopus, can be found almost continuously from Maine to Georgia.Suppose the mice were indeed one single species under the biological species concept.Individuals are collected from across the range and are crossed in the lab.Graph the relationship between viability of hybrids and geographic distance.

Two species of narrowmouth frogs in the United States have mating calls that differ more in their region of sympatry than in those parts of their ranges that do not overlap.If this difference in their vocalizations has the function of preventing hybridization between the two species, it is an example of

Some species of wheat have four sets of chromosomes.This makes them

Refer to the figure. In each of the species of columbine shown, the orientation of the flowers and the length of flower spurs are associated with a particular type of pollinator (hummingbirds or hawkmoths).Columbine flowers vary in other ways as well; for example, they differ in color, and probably in odor.What experiments could you design to determine the traits that various pollinators use to distinguish among the flowers of different columbine species?

Reproductive isolation means that

Which is least likely to evolve via reinforcement?

A field contains two related species of flowering plants.Species A has a diploid chromosome number of 22, and species B has a diploid chromosome number of 26.If a third species arises as a result of hybridization between A and B, how many chromosomes will it have?

Which scenario is least likely to lead to allopatric isolation?

An evolutionary biologist makes decisions about whether to consider different populations of lacewings as separate species, based on observations of the individuals with which these lacewings will mate.This biologist is most likely employing Mayr's _______ species concept, which asserts that reproductive isolation is the most important criterion for identifying species.

Which conclusion is best supported by results of the studies of apple maggot flies?

Which statement about hybrid zones is false?

Which statement about the Dobzhansky-Muller model of speciation is true?

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

Suppose that the natural ranges of horses and donkeys were to overlap.Which statement best describes what is likely to happen to the populations over time?