| [ freeeXpression ] in KIDS 글 쓴 이(By): typhoon (♥한윤수♥() 날 짜 (Date): 1996년04월21일(일) 20시17분18초 KST 제 목(Title): Merrit FAQ : 왜 아메바는 진화안해요? ---------------------------------------------------------------------------- The failure of some organisms to evolve at all. If it passes the selection filter, no change required. These organisms are excellently adapted to their particular niche in their environment. (like sharks: the "perfect eating machine", right?) Like the brachiopod Lingula, and the cockroach, identifiable through most of the phanerazoic and still with us. If an organism is well adapted to a niche it can readily occupy, then why should it evolve? ---------------------------------------------------------------------------- Many species have remained absolutely fixed throughout geologic time. There are no known examples of organisms that have not evolved over a period of time and this includes cockroaches, lungfish, lampreys, sharks, bacteria, and all other organisms that some people claim are "frozen in time". Some of these species appear to be morphologically similar to ancestors that lived in the past but evolution is much more than external appearance. When the structure of their genes and proteins are examined it becomes obvious that they have evolved at the molecular level. In fact the rate of evolution of these species is similar to that of species whose external appearance has changed more drastically. It is incorrect to claim that some organisms have not evolved simply because their external morphology has not changed. The problem here is that the fossil record only preserves some parts of an organism. The fact that these parts have not changed very much doesn't mean that the species has not evolved. -. .-. .-. .-. .-. .- | Yoonsoo Hahn (한 윤 수) ||X|||\ /|||X|||\ /|||X|| | Mol. Genet. Lab, Dept. of Biol. Sci., KAIST |/ \|||X|||/ \|||X|||/ \| | (EMAIL) yshan@sorak.kaist.ac.kr (T) 042-869-5261 ' `-' `-' `-' `-' ` | http://bioneer.kaist.ac.kr/~yshan (P) 015-427-6466 |