Today at 03:56 PM NebraskaMan said this in Post #17
Really? I thought macroevolution was change from potentially one species or "kind" of animal (i.e. dog) to another (i.e. cat); while, microevolution was change within a kind (i.e. siamese cat evolving to a tiger)
First, science doesn't use the word "kind". Creationist alone use it. But they don't have any consistent definition or concept of it. And they have no way to tell whether two organisms are different kinds or not.
Some definitions from evolutionary biologists:
Microevolution is "changes within populations and species".
Macroevolution is "the origin and diversification of higher taxa". Douglas Futuyma, Evolutionary Biology, pg 447, 1998
However, both micro and macroevolution are part of the same process:
"But we must ask, what exactly are these genera, families, orders, and so on? It was clear to Darwin, and it should be obvious to all today, that they are simply ever larger categories used to give names to ever larger clusters of related species. That's all these clusters, these higher taxa, really are: simply clusters of related species.
Thus, in priniciple the evolution of a family should be no different in its basic nature, and should involve no different processes, from the evolution of a genus, since a family is nothing more than a collection of related genera. And genera are just collections of related species. The triumph of evolutionary biology in the 1930s and 1940s was the conclusion that the same principles of adaptive divergence just described -- primarily the processes of mutation and natural selection -- going on within species, accumulate to produce the differences we see between closely related species -- i.e., within genera. Q.E.D.:
If adaptive modification within species explains the evolutionary differences between species within a genus, logically it must explain all the evolutionary change we see between families, orders, classes, phyla, and the kingdoms of life. Niles Eldredge, The Triumph of Evolution and the Failure of Creationism. pgs 76-77.
The site outlines a symbiotic relationship? How does evolution theory account for such a thing?
Quite easily. Evolution of parasitic relationships are easy to explain: one organism gains benefit from letting another organism do part of its work. However, there is a cost: decreased vitality of the host. And when the host dies, so does the parasite. So any variation in the parasite or host that lessens the virulence of the parasite is advantageous. If the parasite assumes part of the burden of keeping
both alive, that variation is going to be selectively advantageous.
Nebraska, you need to
think about what you read and what you are saying. Think about what you read on creationist websites, read what evolution really is, and then think your way through various claims. Is the claim really true? Is there no way for evolution to explain symbiotic relationships? If you
think it thru, you will find the pathway for evolution and natural selection yourself.