ES101 Lecture Notes - Lecture 29: Sympatric Speciation, Darwin'S Finches, Allopatric Speciation

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emeraldyellowjacket960

30 Mar 2018

School

WLU

Department

Environmental Studies

Course

ES101

Professor

Edmund Okoree

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Document Summary

Natural selection can lead to the creation of a new species. This process (called speciation ), occurs when two species arise from one. In this case, a new species is formed when some members of a population can no longer breed through sexual reproduction, with certain other members of the population. We will consider two situations in which speciation can occur: allopatric and sympatric speciation. In general, allopatric speciation is a process of speciation that occurs from long term isolation of two populations of the same species. two phases of allopatric speciation: Geographic isolation: occurs when different groups of the same population become physically isolated from one another for long periods. Example, the darwin finches of the galapagos islands are a classic example of one species" adaptations to the various habitats and resources of the many landscapes and islands of the islands.

Related Questions

Which of the following statements best explains the process of allopatric speciation?

Genetic differences accumulate between populations that are isolated by a geographic barrier, eventually leading to reproductive isolation.

Genetic differences accumulate through recombination between populations that are interbreeding, eventually leading to reproductive isolation.

Genetic differences accumulate in a population through selective mate choice, leading to two groups that breed independently, causing reproductive isolation.

Two populations in the same geographical area accumulate genetic differences by random chance, eventually leading to reproductive isolation.

Genetic changes within a population as the result of genetic drift influences traits involved with mate choice, eventually leading to reproductive isolation.

What is the basic difference between allopatric and sympatric modes of speciation?

Sympatric speciation takes place between populations that migrate away from each other.

Sympatric speciation takes place between populations in the same geographic area.

Allopatric speciation takes place between populations in the same geographic area.

Sympatric speciation takes place over long periods of time; allopatric speciation occurs within a single generation.

Allopatric speciation is thought to occur much less frequently than sympatric speciation.

sangriaswan287

QUESTION 5

The vast numbers of finch species on the Galapagos Islands arevery closely related and differ primarily by feedingspecializations. What process best explains this distribution ofspecies?

		sympatric speciation
		mass extinction
		adaptive radiation
		polyploidy

10 points

QUESTION 6

Frogs "croak" at night to lure females for mating. Females areattracted only to the song of their species. This is an exampleof

		mechanical isolation
		temporal isolation
		habitat isolation
		behavioral isolation

10 points

QUESTION 7

To prepare for a hiking trip in the Appalachian mountains, youbuy several field guides for the region from a used bookstore. Younotice that the older guides list a single species of tigerswallowtail butterfly, Papilio glaucus, and an Appalachianmorph of this species. However, the newest guide list two separatespecies, P. glaucus and P. appalachiensis. Theauthors of this guide state that the biological species concept wasused in determining their classifications. What do you think ledthem to list two separate species of tiger swallowtail?

		The discovery that P. glaucus and P.appalachiensis interbreed in the wild
		The discovery that P. glaucus and P.appalachiensis have a genomic similarity of 99%
		The discovery that P. glaucus and P.appalachiensis do not interbreed in the wild
		The discovery that P. glaucus and P.appalachiensis have distinct differences in wingcoloration

10 points

QUESTION 8

A scientist is studying a population of crickets and finds thatthere is variation in the songs used by males to call for mates.Some males call with high pitched, 3 chirp songs and some call withlow pitched, 4 chirp songs. However, offspring from the two typesof males are able to interbreed, so the scientist classifies thepopulation as a single cricket species and goes on to anotherproject. One year later, a mutation arises in a female cricket thatmakes her unable to hear high frequencies. Ten years later, agraduate student returns to the same cricket population anddiscovers that there are now two distinct cricket species in thearea, although they appear morphologically identical. What is themost likely explanation?

		Temporal isolation has led to allopatric speciation
		Sexual selection has led to sympatric speciation
		Habitat isolation has led to allopatric speciation
		Gametic isolation has led to sympatric speciation