Mutations, bad not good (Introduction)

by dhw, Tuesday, July 19, 2011, 08:21 (4876 days ago) @ Balance_Maintained

TONY: While I can appreciate that Darwin himself did not try to make a clear demarcation between one species and another, I think that it does affect the discussion. If we have no clear delineation between one species and the next, then how can we even begin to discuss evolution proper as a progressive movement from common ancestor to our current state of variety. At some point, there has to be a cut off between the ability to breed between one group and the next, and the point is critical, and I would say central, to the case of Evolution vs. ID. -Before we go any further, I think we need to agree on what we mean by ID. This has become so tainted with Creationism that the words Intelligent Design have lost their meaning. (I've rightly been taken to task over references to this in the "Brief Guide", which is in need of a second revision.) If you mean that life is the product of design, I don't see speciation or evolution as a problem. If you mean that each species was created separately by God, then all species came into being originally without parenthood, and despite the vast range of similarities there is no connection between any of them. Clearly that is in conflict with evolution, and we dive into murky waters. -As I see it, the key to all this is change. If we suppose that every so often changes take place in existing forms of life and continue to take place over millions of years in those forms existing at the time, through adaptations and innovations perhaps stimulated by different environments, it seems reasonable to infer that the process will lead to a wide variety of different creatures. Some will go extinct, some remain the same, some become unrecognizably different. "Species", "sub-species", "varieties" are words we use to categorize, but as Darwin made clear, there are no firm borderlines. If we decide that the borderline is formed by the inability to interbreed, we can argue that eventually ... perhaps over thousands/millions of years ... the changes simply become too radical to allow for interbreeding. It's difficult to imagine a tabby having sex with a tiger, even though they're both felids. In the case of Neanderthals and Homo Sapiens, since apparently they did interbreed, clearly the changes were not so radical, and whether we call them species, sub-species or variations doesn't make any difference to the overall argument. If current scientific findings are to be trusted, early forms of life did not reproduce sexually, did not have wings or legs or eyes or ears or teeth. These innovations could have accumulated over millions of years in many different shapes, sizes and combinations. Atheists may say they came about through adaptations or random mutations, theists may say they came about through God's direct intervention or through a creative mechanism devised by God. And so the choice is not between evolution and design, which are perfectly compatible, but between evolution and the separate creation of species, and maybe of sub-species and varieties. I'd say that a "cut-off " point for interbreeding (ouch, that sounds painful!), when changes have become too radical, would be far less difficult to believe in than creatures which appear fully formed without any act of breeding at all. Wouldn't you?-Dhw: [...] How fast is "fast"? However, if there is a sudden event like, say, a massive eruption or a collision with a meteorite, I would have thought changes would be extremely rapid. Adaptation would certainly need to be swift, but adaptation need not lead to innovations and new species.-TONY: If a organism took a million years, a thousand years, or even a century, to adapt to an environment suddenly turned hostile, I can not conceive how the species would survive long enough to adapt. To slightly altar your question above, "How fast is fast enough?"-We agree that adaptation has to be fast enough to ensure survival, which as I said may = "extremely rapid". Our problem is to account not for species that survive but for the emergence of NEW species. Innovations, even in their most primitive form, would probably need to work immediately, but these and adaptations might be refined, varied, improved over thousands/millions of years and generations, leading to the radical changes described above.