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Posted by Muzzy on January 16, 1999 at 23:48:07:
In Reply to: macroevolution posted by JP on January 16, 1999 at 18:31:10:
: : You said:
: : "As usual, you still fail to comprehend the
: : difference between microevolution which is
: : caused by natural selection, and macroevolution
: : (speciation) which has no known mechanism."
: : Like many other creationists, you acknowledge that microevolution occurs but not macroevolution. Yet all of us supporting evolution say that macroevolution is just a long series of microevolutionary events.
: : Why can't a 10 million- or 20 million-year sequence of microevolution involving millions of generations produce macroevolutionary change?
: Because you have not explained the mechanism for
: this change to occur. MIcroevolution works on
: all ready present genes and changes in the
: frequencies of such and cannot be extrapolated
: to macroevolution. If you think it can, let me
: ask you this question: If we started out with
: a population of bacteria all of which have 1
: chromosome as there entire genetic makeup, how
: can simple variations in these genes and selection,
: after any amount of time, cause organisms with
: say, 8, 20, or 46 chromosomes to appear? These
: genes were never present, how then does natural
: selection work on what is not there?
The mechanism is natural selection. You have already acknowledged that natural selection is responsible for microevolution. The question is why can't a 10 million- or 20 million-year sequence of microevolution involving millions of generations produce macroevolutionary change?