Re: Why did eukaryotes evolve?
- From: "Reason" <pjohnj@xxxxxxxxxxx>
- Date: Fri, 3 Jun 2005 13:39:03 -0400 (EDT)
"James Michael Howard" <jmhoward@xxxxxxxxxxxxxxxx> wrote in message
news:d7obdg$j0v$1@xxxxxxxxxxxxxxxxxxxxxx
> On Thu, 24 Mar 2005 18:00:48 -0500 (EST), hronkko@xxxxxxxxxxxx (Henkka)
> wrote:
>
>>Hi,
>>
>>Would anyone happen to have speculations as to why eukaryotes evolved?
>>In short, what can single-celled eukaryotes (with all of that
>>complicated machinery) do that prokaryotes can't? Engulfing other
>>microbes is one such often-mentioned thing. Any other possibilities?
>>Many protoctists do their living differently - the single-celled
>>algae, for instance. Possibly they are doing something differently
>>from prokaryotes, with whose reproductive efficiency eukaryotes can't
>>compete.
Yes, evolution is much more rapid when genetic traits can recombine from
different individuals. Any short-term benefits derived from efficient
reproduction are eventually nullified by the lack of genetic diversity.
Eukaryotes are able to combine the best assortment of beneficial traits for
survival. A unisexual organism can only evolve very slowly along a single
genetic line, unless it employs an invasive DNA transfer to other organisms
such as with transduction.
Aphids are parthogenic (non-sexual) for most of their life cycle, in order
to keep their numbers high enough to withstand predators, but revert to
sexual reproduction at the end of the cycle. It's likely that any aphid
species that had become totally parthogenic in the past, have become extinct
due to the inability to adapt to their environment quickly enough.
.
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