Study Questions 3-3

Study Questions 3-3 - Thread: Question 1 Post:...

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Unformatted text preview: Thread: Question 1 Post: RE:RE:Question 1 Author: David Schultz Date: Thursday, May 3, 2007 Status: Published Overall rating: Not rated Perfect! Grade: 5 Thread: Question 1 Post: RE:Question 1 Author: Shane Prejean Date: Wednesday, May 2, 2007 Status: Published Overall rating: Not rated The biological species concept has been and continues to be the species concept most frequently used by evolutionary biologists who are concerned with processes of evolution. It was defined by Ernst Mayr in 1942 when he stated, "Species are groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups." Thread: Question 1 Post: Question 1 Author: David Schultz Date: Monday, April 30, 2007 Status: Published Overall rating: Not rated What is a biological species? Thread: Question 2 Post: RE:RE:Question 2 Author: David Schultz Date: Friday, May 4, 2007 Status: Published Overall rating: Not rated OK. Grade: 3 Thread: Question 2 Post: RE:Question 2 Author: Ashley Webre Date: Thursday, May 3, 2007 Status: Published Overall rating: Not rated Reproductive isolation is defined as the restriction of genetic exchange between groups even when those groups are sympatric. The restriction is often not absolute but sufficiently restrictive so that each group maintains a seperate genetic identity because of barriers in gene flow. This means that two different species will either not be able to reproduce because of prezygotic barriers, or they will be able to mate but not produce a healthy fertile hybrid - postzygotic barriers. An example of a prezygotic barrier is mechanical isolation, which is when reproductive structures fail to fit. An example of a postzygotic barriers is hybrid sterility. Horses and donkeys remain reproductivly isolated because when they mate they produce a sterile mule with reduced fitness. A hybrid with reduced fitness will not be selected for, keeping the two species seperate. Thread: Question 2 Post: RE:RE:Question 2 Author: David Schultz Date: Thursday, May 3, 2007 Status: Published Overall rating: Not rated Reproductive isolation does not require a lack of reproduction. It also does not require a lack of hybrids. Grade: 2 Thread: Question 2 Post: RE:Question 2 Author: Lindsay Mayet Date: Thursday, May 3, 2007 Status: Published Overall rating: Not rated Reproductive isolation means that two groups of organisms are unable to exchange genetic information (reproduce). This can occur even when to organisms are not geographically isolated and are sympatric (live in the same area). The restrictions that do not allow for the two groups to reproduce allow each group to maintain its separate genetic makeup without creating hybrids. Reproductive isolations is also the criteria in which separate species are identified. A single species can have a variety of forms, but if two groups are not reproductively isolated, they are considered the same species....
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This note was uploaded on 04/21/2008 for the course BIOL 101 taught by Professor Kilgen during the Spring '08 term at Nicholls State.

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Study Questions 3-3 - Thread: Question 1 Post:...

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