JLT
Posts: 740
Joined: Jan. 2008
|
| Quote (inquiry @ Dec. 07 2009,15:05) | | Quote (JLT @ Dec. 05 2009,17:03) | I accept current evolutionary theory if that is what you're asking. That's more than just natural selection. You do realise that Darwin published his theory 150 years ago and science moved on a bit since then? Actually, for speciation to occur, natural selection wouldn’t even be strictly necessary. Genetic drift alone could, over time, lead to a build up of genetic and/or behavioural incompatibilities in geographically separated populations of a species that might result in reproductive isolation, i.e. they’d become two separate species. Of course, natural selection can contribute to or accelerate this process (once there is a geographical separation).
In plants, speciation frequently involves neo- or allopolyploidy (change in chromosome number), which can result in “instant speciation” |
I could see where this may be possible. Two populations that are isolated from one another could/would go through genetic changes as they adapt to their environment. This could possibly lead to an inability for these populations to interbreed (because of geographical and genetic separation). Also smaller populations tend to genetically drift from the original genetic traits they possessed. And there is more potential in smaller populations for random genetic events. While this is okay in theory there are no known facts to support this theory. |
LOL. So, you agree that this is hypothetically possible but for you it is still more likely that a supernatural entity( for which we don't have any evidence) brings new species into being (for whic we don't have any evidence) by an unknown mechanism?
But I'm sure that you'll rethink your position after you realise that we of course DO have facts to support this theory. Go to Pubmed and search for "drosophila reproductive isolation". On the right hand site you can filter your results for free full text articles.
Unfortunately I'm at work and I've got a visitor this week, so not much time to look trough the articles and do your work for you, but I skimmed a few articles and found this one that is available for free in fulltext: Sexual conflict and reproductive isolation in flies.
They found reproductive isolation after only 41 generations of Sepsid flies. But that wasn't actually the point of the article. They tested the hypothesis whether sexual conflict increases the reproductive isolation between larger populations (of flies). It is not a question anymore that reproductive isolation occurs after few generations, that is an often shown fact, the question has already shifted to the factors that might accelerate or slow down this process.
Btw, Jerry Coyne (the author of Why evolution is true) researches speciation of Drosophila in the wild. In his book he has a chapter about speciation and not surprisingly he talkes mainly about Drosophila in it. With the search terms I mentioned you can also find this article (unfortunately not open access):
INTRINSIC REPRODUCTIVE ISOLATION BETWEEN TWO SISTER SPECIES OF DROSOPHILA.
Matute DR, Coyne JA.
Evolution. 2009 Nov 5. [Epub ahead of print]
The theory of allopatric speciation generates a lot of predictions that can be tested and have been tested successfully both in the lab and in the wild.
IMO it's disingenuous to assert that there aren't any supporting facts if you've never bothered to look for them. I suggested that you go to Pubmed and search for reproductive isolation in the post you quote. Why didn't you do it if you're honestly interested in "where the evidence leads"? How do you think you'll get to know the evidence for the evolutionary theories if you never try to learn anything about it?
| Quote | | Granted the example of plants is an example of speciation. But this type of speciation does not result in a new species. In order for the current evolutionary theory to hold there has to be evidence that a species came to be by splitting off from previous species. |
Where else do these new plant species come from if not from pre-existing plant species?
Interesting article in PNAS: http://www.pnas.org/content/early/2009/08/05/0811575106.abstract
| Quote | | By combining information from the botanical community's vast cytogenetic and phylogenetic databases, we establish that 15% of angiosperm and 31% of fern speciation events are accompanied by ploidy increase. These frequency estimates are higher by a factor of four than earlier estimates and lead to a standing incidence of polyploid species within genera of 35% (n = 1,506). |
So, probably one of the most important speciation mechanism in plants doesn't count because you don't like and/or understand it?
--------------
"Random mutations, if they are truly random, will affect, and potentially damage, any aspect of the organism, [...]
Thus, a realistic [computer] simulation [of evolution] would allow the program, OS, and hardware to be affected in a random fashion." GilDodgen, Frilly shirt owner
|
