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why has Casandra not evolved for such a long time ?..have the oceans really not changed that much in such a long time ?
Are there any other examples of non-evolution over such a great expanse of time ? flora ? fauna ? other ?
Quote from: neilep on 26/08/2008 22:45:49why has Casandra not evolved for such a long time ?..have the oceans really not changed that much in such a long time ?Deep ocean conditions have not changed for eons, and the laws of hydrodynamics which shaped Casandra are constant.QuoteAre there any other examples of non-evolution over such a great expanse of time ? flora ? fauna ? other ? In this thread our not-so-tame creationist Asyncritus has been claiming coelacanths (another deep ocean fish) have not changed in 418Myr.The phrase "non-evolution" is incorrect: evolution never stops. The form of some creatures who have become ideally adapted to a constant niche may have changed little over millions of years, but evolution has still changed them during this period, e.g. new pathogens will exert an evolutionary pressure on their immune systems. New pathogens are constantly being created by evolution. Those creatures whose immune system can defeat the new virus survive and pass on this immunity to their progeny. Those whose immune system cannot defeat the new virus perish and are an evolutionary dead-end.So Cassandra's immune system, and possibly brain/behaviour and other systems (e.g. olfaction) will not be the same as her look-a-like fossilized ancestors: evolution has never stopped in her case, or any other species.
Sharks do get cancer .As our resident creationist Asyncritus has correctly pointed out, most genetic mutations are either destructive or neutral, only a tiny minority are beneficial.Cancer is one of those destructive genetic mutations, which can affect all creatures, (including sharks).