Posted on 01/26/2006 11:47:13 AM PST by PatrickHenry
They could eventually through interbreeding.
What if a particular species were separated by great distances?
That would be a barrier to interbreeding.
If they were in close proximity to one another, would genetic drift affect all of them at the same time?
Genetic drift is not an "effect", it's a result. Nor is it something that can be coherently described as happening "at the same time". It's what happens when differential reproductive sampling occurs across generations.
I can make a strong argument that evolution is not driven randomly...
there would be sudden emergences on all time scales.
Now you lost me.
in some ways physics is less empirical than biology.
Nope. The point eh authro is making is that sudden changes, even sppeciation, comes about as a result of selective (or environmental) pressure... Nothing at all to do with ID or creationism.
http://www.freerepublic.com/~patrickhenry/#herd
Very well-written, clear, and persuasive.
Well done!
Nope. The point the author is making is that sudden changes, even speciation, comes about as a result of selective (or environmental) pressure... Nothing at all to do with ID or creationism.
mutation rates not only climb, but the such mutations (non-lethal) can also accumulate in the gene pool over successive generations.
All of which actually dovetails nicely with punctuated equilibrium. It appears the theory is about sudden phenotypical appearance of relatively small changes which still have to accumulate to get anywhere.
Schwartz's choice of characterizations of his theory will feed a new generation of Luddites, though. Some are already saying it works well with ID. Others will mock it as more "Hopeful Monster" nonsense. (It sounded overly saltational to me at first, but I think I see what he's saying now.)
"Would all of the particular species acquire legs?
Because the original allele is recessive, as drift causes more and more of the population to include that particular allele in their genome, individuals within the population will occasionally 'pop' up wearing a brand new set of 'legs'. (the legs may just be modification or slight addition). The 'legs' would occur in roughly 25% of the offspring of parents where each parent had at least one 'leg' allele.
"What if a particular species were separated by great distances? "
If they were unable to breed with the 'mutated' population they would be considered a different species. As long as there is very little or no gene flow between the two populations the mutation would affect only the one population. However this really depends on the amount of gene transfer between the populations.
"If they were in close proximity to one another, would genetic drift affect all of them at the same time?
Genetic drift depends on quite a number of factors, but the gene flow between populations, and the population size are very important to the speed and success of the allele fixing in a population. A small population with little injection of alleles from an outside population is the best scenario for drift to occur. As soon as a few critters are born with both recessive alleles and they start having their own little critters, selection takes effect and determines the survivability of the mutation.
Thanks. I think. :)
It can be reduced to simple mathematical models based on population size. If I remember correctly.
As in, "to jump?" Can you pronnounce that word? lol!
Yeah, I agree, the word, "Origin," alone will bring undiscerning readers who are also "luddites" to believe they've found a new champion.
"Jumpy" would be more idiomatic, I suppose.
There are two simple equations for the frequency of two alleles of a given gene (see Hardy-Weinberg principle):
Equation 1:p2 + 2pq + q2 = 1
Equation 2: p + q = 1
Where p is the frequency of one allele and q is the frequency of the other allele. p2 is the population fraction that is homozygous for the p allele, pq is the frequency of heterozygotes and q2 is the population fraction that is homozygous for the q allele. Natural selection can act on p and q in Equation 1, and obviously affect the frequency of genes seen in Equation 2. It should be noted that the second equation can be derived from the first (or vice versa) since p2 + 2pq + q2 = 1 implies (p + q)2 = 1 and p and q are positive numbers.
Thank you.
What parts need expanding?
After many years teaching neurophysiology, I got used to the pronnounciation of saltatory and when I tried to use the same syllabic emphasis on saltational and I had a brain fart...I'm going out for some fresh air.
Very good.
However the H-W equation will only give you the probable percentages of the combinations. What else do we need to do?
Nothing yet. lol Just let me absorb a little at a time.
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