Chapter 27: speciation

Which of the following have operated to increase divergence between mosquitofish on Andros ?

(3 and 5) sexual and natural selection

Which of these habitats is likely to harbor the most recently diverged species ?

A1

In spring species A goes to east coast and B goes to west coast what can you say about the isolating mechanisms of these two species ?

Their winter habitat has no bearing on their degree of reproductive isolation

D. Santomea _____

Descended from an original colony of D. Yakuba

These two juniper species are kept separate by ____

Gametic isolation

Should the two forms of moths be considered separate species ?

No

Both male and female hybrids exist, but when they mate among themselves they are rarely successful in producing offspring. What can you infer from this information ?

Postzygotic isolation exists between the two frogs species

Based on these results if this type of tetraploid fromed in the wild, what would be the result ?

The tetrapods would be reproductively isolated from both parent species

The diploid number for species C would probably be ___

28

Rank the following in order from most general to most specific

2,4,1,3

What would be the likely diploid number (2n) of the allopolyploid ?

32

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

A behavioral reproductive isolating mechanism

The largest unit within a gene flow can easily occur is ___

A species

The Panama Canal was completed in 1914, after 1914 snapping shrimp species from which habitats should be most likely to form hybrids as a result of the Canal ?

A1 and B1

Which habitats should harbor snapping shrimp with the greatest degree of genetic divergence from each other ?

A5 and B5

If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ______

Allopatric speciation

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

Allopatrically, after the ancestral species has split into two populations

A hybrid zone is properly defined as ___

An area where mating occurs between members of two closely related species producing viable offspring

The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and ____

An increasing number of viable fertile hybrids is produced over the course of the next one hundred generations

Which of the following statements explain why animals are less likely to speciate by polyploidy ?

Animals self-fertilize less often than plants

In which habitat should one find snapping shrimp closely related to shrimp that live in habitat A4 ?

B4

Fighting other males and making stylized movements that attract females, what type of reproductive isolation does this represent ?

Behavioral isolation

Which type of isolation operated to keep mosquito fish isolated even when fish from diff ponds are reunited in the same body of water ?

Behavioral isolation

Which of the following statements about species as defined by the biological species concept is correct ?

Biological species are defined by reproductive isolation and all members of a species can potentially interbreed (I and III)

what is the best way to promote fusion between two related mosquitofish, one of which lives in a predator-rich pond and the other of which lives in a predator-poor pond ?

Build a canal linking the two ponds that permits free movement of mosquitofish but not of predators.

Myrtle warbler and Audubon warbler recently have been classified as eastern and western forms of a single specie, what would cause this reclassification ?

The two forms interbreed often in nature and their offspring have good survival and reproduction

If reinforcement is occurring what would you expect if you compare the calls of the two species in zones of sympathy versus zones of allopathy ?

Calls would be more different in areas of sympatry

The two populations are ___

Different subspecies, under the morphological species concept

Females tend to mate where they feed, the researcher finds a genetic basis for scent preference in these moths. What might be occuring in the moth specie ?

Divergence in sympatry

Refer to the figure above, which of the following forms a monophyletic group ?

E, F and G

What does the biological species concept use as the primary criterion for determine species boundaries ?

Gene flow

Which of the following does not tend to promote speciation ?

Gene flow

In hybrid zones where reinforcement is occurring we should see a decline in ____

Gene flow between distinct gene pools

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

Genetic isolation, genetic drift, divergence

If snapping shrimp avoid swimming at night and avoid swimming under shadows, then what do these bridges represent ?

Geographic barriers

If the isthmus formed gradually rather than suddenly what pattern of genetic divergence would you expect to find ?

Greater percentage of DNA sequence between species that inhibit deep water than between species that inhabit shallow water

Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms ?

Habitat isolation

What keeps the two separate ?

Habitat isolation

Which of the following reduces gene flow between the gene pools of the two species on sao tomè

Hybrid sterility

Reinforcement is most likely to occur when ____

Hybrids have lower fitness than either parent population

If no species can hybridize, then which of the following statements about species W and Y are true ?

I, II and III

What outcomes could possibly occur where the ranges of two species overlap?

I, II and III

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

Plant gametes can be produced by meiosis from somatic cells that have undergone many rounds of mitosis

Most causes of speciation are relatively slow, in that they may take many generations to see changes with the exception of _____

Polyploidy

The frogs are identical in appearance but their mating calls differ. Which difference most likely evolved first ?

Polyploidy

The difference between geographic isolation and habitat isolation is the ____

Relative locations of two populations as speciation occurs

The origin of a new plant species by hybridizing two existing species, coupled with accidents during cell division is an example of ____.

Sympathetic speciation and allopolyploidy

Among known plant species which of these have been the two most commonly occurring phenomena that have led to the origin of new species ?

Sympathetic speciation and polyploidy

The host mammal can be considered as the fleas habitat. If this situation persists and new species evolve this would be an example of _____

Sympatric speciation and habitat isolation

A particular variant of the beetle prefers the red flowers to the orange. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible

Sympatric speciation, habitat differentiation

About twice a year, one or two more birds from the neighboring island arrive. These new arrivals ____

Tend to retard adaptation to the new food plants

Suppose that a group of male pied flycatchers from a region where there were no collared flycatchers to a region where both species were present. Assuming events like this are very rare, which of the following scenarios is least likely?

The frequency of hybrid offspring would decrease

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

The level of water in a lake recedes, creating two lakes where there used to be one

The sister populations on opposite sides of the isthmus are true species under which species concept ?

The morphological species, biological species and phylogenetic species concept

Which factor is most important for explaining why there are equal numbers of snapping shrimp species on either side of the isthmus ?

The relative shortness of time they have been seperated

What should deep water shrimp on different sides of the isthmus have diverged from each other earlier than shallow water shrimp ?

They have been geographically isolated from each other for a longer time

The ants can not swim so now they are in multiple isolated populations. Which of the following best describes this event ?

This situation represents isolation by vicariance

If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are porrly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, these conditions will most likely lead to ____

reinforcement

The data in the previous graphs indicate that ____

two-way migration of squirrels occurred across the bridge, but without hybridization