Please Help: Speciation?

Question

1. Why does allopolyploidy pobably produce more variation than autopolyploidy?

2. How can disruptive selection lead to speciation in sympatric populations of the same species?

3. How may a hybrid zone eventually lead to the extinction of species?
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1. ? I think it's because allopolyploidy is more common, whereas autopolyploidy is rare. Also something to do with the fact that autopolyploidy happens within a species but allopolyploidy happens withing different species interbreeding.

2. ???
3. ???
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Please help explain these to me, I don't really understand the concepts so I'm having trouble answering these. My book isn't helpful either, it's vague, and doesn't go in depth with any of these. It's also confusing.
I would really appreciate the help. Thank You! = )

Answer 1

Autopolyploidy is doubling of the same chromosome set, while allopolyploidy is interbreeding and variant chromosome sets are introduced into the 'ploidy. So, you can see why allopolyploidy produces more variation and you deduced the answer correctly.

Answer 2

Question 3: When populations are separated and begin to speciate, there is a time during which they can continue to interbreed, but the offspring are infertile hybrids. If there is too high a percentage of these hybrids, the species can go extinct.

Answer 3

Micro-evolution is defined as the change of allele frequencies within a population over time and can include speciation within the kind. Even a mutation creating a new allele falls within this definition since the organism remains in the same kind. Macro-evolution requires the formation of new genetic information and changes beyond the boundaries of the kind. If you are after Creationist justification for these definitions it is that God created all things to reproduce after their kind. Even Linnaeus recognised that kind did not correspond exactly with his taxonomic divisions. Yes I have looked at the TO list of speciation and they are all within the existing kind and are examples of micro-evolution. Biologists have trouble precisely defining species and creationists have trouble determining the boundaries of kind. That doesn't make either concept unusable. Evolutionists are also adept at changing the definitions of their terms (such as vestigial) so Creationists need not apologise for refining their definitions where necessary as biological knowledge improves.

Answer 4

I'm not sure on your answer to number 1, and I'm not sure of number 3 either. I'm sure I learned these, and I can look them up for you in my texts on Tuesday. As far as #2 goes, though, if you're taking two species and hybridizing them (like with whitetail deer and mule deer) it could come to the situation where they're so interbred they become one interbreeding population, with no pure whitetail deer left and no pure mule deer left. All would be hybrids, in which case you went from 2 separate species down to 1 hybrid species. Make sense?
Feel free to email me at
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about the other 2 questions and I can look them up for you on Tuesday.
Best of luck! - kevin