Sunday, April 4, 2010

Allopolyploid and Autopolyploid Speciation

Allopolyploid speciation and autopolyploid speciation are described by Coyne as two special forms of sympatric speciation that can give rise to new species in our lifetimes (p.186). Distinguish between and explain the two forms of sympatric speciation and compare/contrast polyploidy with other types of speciation. Creationists use the point that evolution cannot be true because it cannot be observed. Explain how polyploidy can be used to refute creationist arguments. Describe what implications you think this may have in terms of natural selection. Also comment on the use of polyploidy plants, such as wheat and bananas, as food products. Don’t forget to provide some examples.

3 comments:

  1. Sympatric speciation is the process by which new species arise from a common ancestor while in the same general area. They are not separated by a geographic structure that keeps them from mating. The idea that different species can arise from a common ancestor in the same place is still up for debate because it is unlikely that species will diverge because they will often interbreed, undoing speciation.
    However, sympatric speciation can be observed in plants. There are two types: allopolyploid speciation and autopolyploid speciation. Allopolyploid speciation is the "hybridization of two different species that live in the same area" (Coyne, 186). This means that two different species end up mating, producing a hybrid. However, in order for this to be actual speciation, the hybrid must be infertile with the two species that gave rise to it. If plant A mates with plant B to produce hybrid plant C, then in order for it to be true speciation, plant C must not be able to reproduce with plant A or plant B. This most likely occurs when the two parent plants have different numbers of chromosomes. Therefore, in order to be able to produce viable, nonsterile offspring, the number of chromosomes in the hybrid would have to double. Then, this hybrid would be fertile, but unable to reproduce with the two species of plants that gave rise to it. This is allopolyploid speciation. An example of this is in species of plants in the genus Arabidopsis. Also, wheat is a common example of allopolyploid speciation, arising from three separate species.
    http://www.epidna.com/showabstract.php?pmid=10999418

    The other type of sympatric speciation is autopolyploid speciation. Autopolyploid speciation is a process in which a new species arises when the number of chromosomes in a single species is doubled. The offspring has twice the chromosomes and thus cannot mate with the original species, however, it can still reproduce with other autopolyploid plants. Potatoes are an example of autopolyploids.
    http://en.wikipedia.org/wiki/Polyploidy

    In the case that creationists and ID proponents make that evolution cannot be observed, therefore, cannot be true. I say have faith...
    Or, you could just observe simple sympatric speciation in plants. New species of plants arise due to mutations in the number of chromosomes. This can be tested for and observed. New species arise, sounds like evolution to me.

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  2. I believe that God created everything.
    My problem with evolution is not that speciation can't be observed...rather that all things are under the control of Almighty God, including speciation.

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    1. "all things are under the control of almighty god", if that is true, your god is a real jerk!

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