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Pastimes : Let's Talk About Our Feelings!!! -- Ignore unavailable to you. Want to Upgrade?

To: epicure who wrote (41281)	6/21/1999 1:39:00 AM
From: Chuzzlewit	Read Replies (1) \| Respond to of 108807

Evolution simply means that organisms change over time. Nothing else. That is why I am saying that you have confused the observation with the explanation (theory). Other examples of evolution are the independent creation of phenotypes having the identical effect -- like beta thallasemia, Cooley's anemia and sickle-cell anemia all providing protection against the most virulent forms of malaria. But the mutations are different in each case. Various theories of evolution have been promulgated to explain the observed fact of evolution. For example, Lamarck proposed that organisms change in response to a changing environment by use. From a very simplistic view: Giraffes grew long necks because the leaves from lower hanging branches of trees were harder to reach. This is an example of post-adaptation. Darwin proposed a system of pre-adaptation -- the change (longer necks) pre-dated the need for longer necks. Then, when leaves were harder to reach natural selection favored those animals with longer necks. Non-Darwinian evolution simply means that one or more of Darwin's proposed mechanisms are unnecessary or wrong. For example, Darwin thought that all evolutionary changes were adaptive. But there is a considerable body of evidence to indicate that this is not always true, and that even when changes are adaptive they may not be of sufficient magnitude to overcome the effects of drift. That explains why evolution seems to occur much faster in small "pioneer" populations. Viruses are organisms, just like bacteria, protozoa, fungi and a host of other acellular and single celled organisms. There is no need to postulate sexual reproduction to account for evolution. There is nothing problematic about evolution in viruses or bacteria. In fact, they are ideal organisms for study because of their extremely short life cycles and genetic simplicity. The initial appeal for fruit flies in evolutionary studies was prompted by the same consideration. The toad story is well-know, but too complicated to rehash here. It can be found in many thorough texts on speciation. I suggest Ernst Mayr's Animal Speciation and Evolution as a source for this as well as a thorough going fully-documented (although dated) review of the literature on speciation in animals. CTC