Exam 26: Speciation

A small number of birds arrive on an island from a neighboring larger island.This small population begins to adapt to the new food plants available on the island,and their beaks begin to change.About twice a year,one or two more birds from the neighboring island arrive.What effect do these new arrivals have?

If a plant species with 2n = 14 forms an allopolyploid with a plant species with 2n = 18,what would be the likely diploid (2n)number of the allopolyploid?

A population of ground squirrels is separated by a glacier.Changes in which of the following would most likely result in reproductive isolation if the two populations came into contact several generations later?

Which of the following does not tend to promote speciation?

The peppered moth provides a well-known example of natural selection.The light-colored form of the moth was predominant in England before the industrial revolution.In the mid-nineteenth century,a dark-colored form appeared.The difference is produced by a dominant allele of one gene.By about 1900,approximately 90% of the moths around industrial areas were dark colored,whereas light-colored moths were still abundant elsewhere.Apparently,birds could readily find the light moths against the soot-darkened background in industrial areas and therefore were eating more light moths.Recently,use of cleaner fuels has greatly reduced soot in the landscape,and the dark-colored moths have been disappearing.Should the two forms of moths be considered separate species?

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?

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

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?

You are studying lizards in the field.The range of the northern population,species 1,overlaps the range of the southern population,species 2.You find hybrids in the zone of overlap.What is happening?

Several stickleback species live in sympatry.These species exhibit morphological divergence as they each exploit either the benthic (bottom)or the limnetic (deeper,open-water)environment.Occasionally,the two kinds mate,resulting in hybrid offspring.Which of the following is a potential reason for maintenance of these two separate groups despite the occasional hybridization event? A)Hybrids share traits of both species,and thus are specialized and able to hunt well in either environment. B)Hybrids share traits of both species,and thus are able to attract mates of either species. C)Hybrids share traits of both species,and thus are not specialized to either environment in terms of hunting. D)Hybrids share traits of both species,and thus may not have specific traits to attract mates of either species. E)Both A and B. F)Both C and D.

Which of the following describes the most likely order of events in speciation?

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 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?

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

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 storm brings two formerly separated populations of beetles together.They look very similar.Under the biological species concept,which of the following would show that the two populations are different species?

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 Altantic 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?

Why is speciation by polyploidy more likely in plants than in animals?

You want to study divergence of populations,and you need to maximize the rate of divergence in order to see results within the period of your grant funding.You will form a new population by taking some individuals from a source population and isolating them so the two populations cannot interbreed.What combination of characteristics would maximize your chance of seeing divergence in this study? 1. Choose a random sample of individuals to form the new population. 2) Choose individuals from one extreme to form the new population. 3) Choose a species to study that produces many offspring. 4) Choose a species to study that produces a few,large offspring. 5) Place the new population in the same type of environment as the source population. 6) Place the new population in a novel environment compared to that of the source population.

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