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The snake family Typhlopidae consists of small, burrowing species with vestigial eyes. They are found in Australia, sub- Saharan Africa, India and some adjacent areas, and South America. What is the most likely explanation for this distribution?


A) convergent evolution in the different regions
B) rafting to the different continents from the point of origin on one of these continents
C) origin on Gondwana followed by continental drift and some range expansion
D) all of the above

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Which of the following could be a vicariance event for species in that habitat?


A) Nonnative rats are introduced to an island by human explorers.
B) Radiation near Chernobyl increases mutation rate, causing an increase in autopolypolidy.
C) Some insects get blown in a storm to a new mountain range, where they lay eggs.
D) The level of water in a lake recedes, creating two lakes where there used to be one.

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Natural selection for traits that keep distinct populations from reproducing with each other is called reinforcement. When is reinforcement beneficial?


A) when prezygotic isolating mechanisms are in place
B) when populations would otherwise fuse over time
C) when hybrids have lower fitness than either parent population
D) when one population could be overwhelmed by the other

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Use the following information when answering the corresponding questions) . About 3 million years ago, the Isthmus of Panama a narrow strip of land connecting North and South America) formed, divid marine organisms into Pacific and Caribbean populations. Researchers have examined species of snapping shrimp on both sid isthmus. Based on the morphospecies concept, there appeared to be seven pairs of species, with one species of each pair in the Pacific and the other in the Caribbean. The different species pairs live at somewhat different depths in the ocean. Using mitochondrial DNA sequences, the researchers estimated phylogenies and found that each of these species pairs, separated by the isthmus, were indeed each other's closest relatives. The researchers investigated mating in the lab and found that many species pairs were not very interested in courting with each other, and any that did mate almost never produced fertile offspring. N. Knowlton, L. A. Weigt, L. A. Solorzano, D. K. Mills, and E. Bermingham. 1993. Divergence in proteins, mitochondrial DNA, and reproductive incompatibility across the Isthmus of Panama. Science 260:1629- 32.) -Which of the following describes the most likely order of events in speciation?


A) divergence, genetic isolation, genetic drift
B) genetic isolation, divergence, genetic drift
C) divergence, genetic drift, genetic isolation
D) genetic drift, genetic isolation, divergence
E) genetic isolation, genetic drift, divergence

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Which of the following reproductive barriers would prevent a mating attempt?


A) behavioural isolation
B) gametic isolation
C) sexual selection
D) hybrid sterility
E) mechanical isolation

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Which of the following is a disadvantage of the morphological species concept?


A) Two groups may use very similar resources, but be evolutionarily independent.
B) It is subjective in nature, with differences of opinion that cannot be resolved by data.
C) Reliable information exists only for a small number of organisms.
D) It cannot be used to evaluate fossils.

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Six potential species of seaside sparrows were genetically analyzed to determine their phylogenetic relationships. DNA analysis revealed that there were only two monophyletic groups with individuals from three subspecies making up each group. The three Atlantic coast subspecies formed one monophyletic group, while the three Gulf coast subspecies made up the other monophyletic group. If you could only save two subspecies of the seaside sparrows from extinction, would you choose two subspecies from the Atlantic coast, two from the Gulf coast, or one each from the Atlantic and Gulf coasts?


A) Save two subspecies from the Atlantic coast, as this coastline is longer and more likely to provide habitat for the birds.
B) Save one each from the Atlantic and Gulf coasts to preserve more genetic diversity.
C) Save two subspecies from the Gulf coast, as this area is much warmer and birds are more likely to survive.

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A population of earthworms lives on an island in the middle of a river. Damming of the river causes flooding on the island, and only the highest points remain above water, creating several smaller islands with Now- separate earthworm populations on them. The earthworms cannot swim. Which of the following best describes this event?


A) The earthworms have undergone speciation by sympatry.
B) The earthworm populations will still have gene flow between them.
C) The earthworm populations have been isolated by vicariance.
D) The earthworms have undergone speciation by allopatry.
E) The earthworm populations have been isolated by dispersal.

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A species of groundhog spreads through an environmentally varying region surrounding a lake; the different populations, each in their own environments, accumulate habitat- specific morphological traits. Which of the following is this an example of?


A) species cluster
B) sub- species
C) allopatric speciation
D) founder effect

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A researcher notices that in a certain moth species, some females prefer to feed and lay eggs on domesticated solanaceous plants like potatoes and tomatoes. Other females prefer to feed and lay eggs on wild solanaceous plants like Datura. Both male and female moths primarily use scent to find these plants from afar. Females tend to mate where they feed, and the researcher finds a genetic basis for scent preference in these moths. Based on the above information, what might be occurring in this moth species?


A) divergence due to vicariance
B) postzygotic isolation
C) divergence in sympatry
D) polyploidization

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Most causes of speciation are relatively slow, in that they may take many generations of organism to see changes, EXCEPT


A) colonization.
B) vicariance.
C) polyploidy.
D) natural selection.

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Two species of tree frogs that live sympatrically in the northeastern United States differ in ploidy: Hyla chrysocelis is diploid, and Hyla versicolor is tetraploid. The frogs are identical in appearance, but their mating calls, which females use to find mates, differ. Which difference most likely evolved first?


A) polyploidy
B) difference in mating calls
C) A and B must have occurred at the same time.

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How are two different species most likely to evolve from one ancestral species?


A) phylogenetically, due to heterozygote advantage in hybrids
B) allopatrically, after the ancestral species has split into two populations
C) sympatrically, by a point mutation affecting morphology or behavior

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In hybrid zones where reinforcement is occurring, you should see a decline in


A) speciation.
B) mutation rates.
C) gene flow between distinct gene pools.
D) hybrid sterility.
E) the genetic distinctness of two gene pools.

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The peppered moth has a light and dark colour morph; the light morph was common in pre- industrial England. Increased pollution during the Industrial Revolution allowed dark morph moths to camouflage effectively against the dark, sooty background. Consequently, the dark morph became more common in industrial areas while the light morph remained common elsewhere. Recently, dark morph moths have been decreasing with reductions in pollution. Should the two morphs be considered separate species?


A) No, because they are not in allopatry.
B) Yes, because the dark and light morphs have higher fitness in different habitats.
C) Yes, because natural selection has acted on the frequency of the two forms.
D) Yes, because they have very different phenotypes.
E) No, because there is no evidence that they are reproductively isolated.

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What keeps the two populations separate?


A) lack of hybrid viability
B) behavioural reproductive isolation
C) gametic barrier
D) geographic reproductive isolation
E) temporal reproductive isolation

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Three populations of crickets look very similar, but the males have courtship songs that sound different. What function would this difference in song likely serve if the populations came into contact?


A) both a prezygotic and a postzygotic isolating mechanism
B) intrasexual selection between a male of one population and males of the other two populations
C) intersexual selection between a male of one population and females of the other two populations
D) a prezygotic isolating mechanism
E) a postzygotic isolating mechanism

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Which of the following statements explains why animals are less likely than plants to speciate by polyploidy?


A) Animals are more mobile, so populations get separated far less often.
B) Animals are better at recognizing appropriate mates.
C) Animals have better mechanisms for repairing chromosomes than plants have.
D) Animals self- fertilize less often than plants, so diploid gametes are less likely to fuse.

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Which of the following evolutionary processes is not acting when two groups of organisms are identified as different species according to the Biological Species Concept?


A) mutation
B) gene flow
C) sexual selection
D) natural selection
E) genetic drift

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House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges meet, what would this situation illustrate?


A) sympatric speciation
B) vicariance
C) allopolyploidy
D) autopolyploidy
E) allopatric speciation

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