natural selection

[Starboy]

Quote by: Agent007 Pooeypants, do not belittle me. Behavior is instinctive,

Don't you mean 'some' behavior is instinctive?

Starboy

[LogicaLunatic]

Hi!

Read!

http://www.talkorigins.org/faqs/faq-speciation.html

[Pooeypants]

Quote by: Agent007 Pooeypants, do not belittle me. Behavior is instinctive, but you did not understand what I wrote in my post. Truly, if a twig-eating population's environment changed from a place with only twigs to one with twigs and caterpillars, then it is possible for a mutated organism to adapt in order to eat both twigs and caterpillars. If its offspring get the trait to eat both foods through heredity and they live in the same environment, then their food would be both as well. However, if a mutation occurred so that the organism can eat only mushrooms, and there were no mushrooms in the environment, then it would die, and all other organims mutated like so would perish as well in that environment. Heredity does not necessarily ensue in organisms' offspring from eating twigs and leaves because environments change over time. Populations that do not adapt properly are those that are wiped out like the organisms that eat only mushrooms.

Okay, so where does this lead us? You've pretty much mention stuff that I have no quarry with.

[jeafl]

Quote by: Starboy I think you are playing semantics here. A change in a "detrimental" trait that benefits a species is still a change.

When have I said otherwise? I'm simply trying to figure out exactly what natural selection does. As far as I have been able to determine ns works to both perpetuate traits that increase fitness and eliminate trates that reduce fitness. To this I would add nature's ability to preserve as much genetic diversity as it can even when that diversity is at a disadvantage so the offspring of current populations will have a large gene pool to draw on in order to meet future environmental conditions. This preservation may not what Darwin expected, but it may be what God designed.

So you think that Darwin’s theory represents the current understand of evolution?

What has this to do with the topic at hand? I find it utterly amazing that Darwinists seldmon wish to called Darwinists. Is modern evolutionary theory not based on natural selection- which is what Darwin proposed?

[jeafl]

Quote by: Pooeypants Sickle cell anaemia occurs in West Africa and India. However, the mutations which causes the same phenotype in both set of populations is identical but the replacement mutation is at a different location. Although we're talking about same species, I'm pretty confident these two populations don't readily interbreed and even if they did, it wouldn't explain why two genotypes of HbS exists. What links them together though, is the threat of Malaria and I'm sure you're well aware that heterozygous HbS have increase resistance to the Plasmodium parasite.

I have never been aware that the concept of convergent evolution has ever been applied to the same species.

But anyway, is it not possible that the Africans and Indians share a common ancestor that originated the sickle cell trait, but then over time the location of the sickle cell gene was moved due to a chromosomal recombination event? I don't know right off how common recombination is in humans, but could it explain sickle cell?

[Starboy]

Quote by: jeafl When have I said otherwise? I'm simply trying to figure out exactly what natural selection does. As far as I have been able to determine ns works to both perpetuate traits that increase fitness and eliminate trates that reduce fitness. To this I would add nature's ability to preserve as much genetic diversity as it can even when that diversity is at a disadvantage so the offspring of current populations will have a large gene pool to draw on in order to meet future environmental conditions. This preservation may not what Darwin expected, but it may be what God designed.

Perhaps there is a god and perhaps it did design something but before that idea has any credibility one would have to produce god and produce its plans and show that what currently exists is what is in those plans. Anything else is just an act of faith. But if you are interested in evolution then perhaps you should read the modern versions of ToE.

What has this to do with the topic at hand? I find it utterly amazing that Darwinists seldmon wish to called Darwinists. Is modern evolutionary theory not based on natural selection- which is what Darwin proposed?

Because science has moved on but apparently you have not.

Quote by: Wilipedia One of the first coherent theories of biological evolution was proposed in the early 19th century by Jean-Baptiste Lamarck, though it did not meet with widespread approval. With the publication of Charles Darwin and Alfred Russel Wallace's joint paper in 1858 followed by Darwin's book Origin of Species in 1859, the theory of evolution by natural selection became firmly established within the scientific community and rapidly caught the public imagination. In the 1930s, work by a number of scientists combined Darwinian natural selection with the re-discovered theory of heredity proposed by Gregor Mendel to create the modern evolutionary synthesis. In the modern synthesis, "evolution" means a change in the frequency of an allele within a gene pool. This change may be caused by a number of different mechanisms: natural selection, genetic drift or changes in population structure (gene flow).

However it is not as if the whole thing is settled. The explanation has moved to the molecular biophysics level. Scientists are trying to account for just exactly how the alleles change. There is now more to evolution than just natural selection.

Starboy

[jeafl]

Quote by: Agent007 Pooeypants, do not belittle me. Behavior is instinctive, but you did not understand what I wrote in my post. Truly, if a twig-eating population's environment changed from a place with only twigs to one with twigs and caterpillars, then it is possible for a mutated organism to adapt in order to eat both twigs and caterpillars. If its offspring get the trait to eat both foods through heredity and they live in the same environment, then their food would be both as well. However, if a mutation occurred so that the organism can eat only mushrooms, and there were no mushrooms in the environment, then it would die, and all other organims mutated like so would perish as well in that environment. Heredity does not necessarily ensue in organisms' offspring from eating twigs and leaves because environments change over time. Populations that do not adapt properly are those that are wiped out like the organisms that eat only mushrooms.

Would eating habits be totally instinctive, that is gene based? Consider what happens in human populations that face famine. During the Union siege of Vicksburg, Mississippi food was so scarce that it has been said no rat survived. Since humans (at least in the U.S. and possibly Europe) do not generally eat rats, what kind of genetic input determined the Vicksburgers diet?

[Pooeypants]

Quote by: jeafl I have never been aware that the concept of convergent evolution has ever been applied to the same species. But anyway, is it not possible that the Africans and Indians share a common ancestor that originated the sickle cell trait, but then over time the location of the sickle cell gene was moved due to a chromosomal recombination event? I don't know right off how common recombination is in humans, but could it explain sickle cell?

Or maybe there's an easier explanation. Both populations are subjected to the same selection pressure; Malaria and the resistance conferred from being a heterozygote of HbS.

Anyway, how exactly does a recombination event change the point mutation location? I'm not familiar with how that works...