Re: Evolution of Separate Genders in Animals

On Mar 6, 10:29 am, "hersheyh" <hershe...@xxxxxxxxx> wrote:
On Mar 5, 9:53 pm, "derdag" <der...@xxxxxxxxxxxxxxxxxxxx> wrote:





On Mar 5, 8:45 pm, "Perplexed in Peoria" <jimmene...@xxxxxxxxxxxxx>
wrote:

"rmj" <gle...@xxxxxxx> wrote in messagenews:uy2Hh.6944$PL.1839@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

"Perplexed in Peoria" <jimmene...@xxxxxxxxxxxxx> wrote in message
news:FO0Hh.463$yW.438@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx

"r norman" <r_s_norman@xxxxxxxxxxxx> wrote in message
news:e85pu2h8hhqoosdk1fpfcl0leddcn8cj6s@xxxxxxxxxx
On 5 Mar 2007 12:09:35 -0800, "hersheyh" <hershe...@xxxxxxxxx> wrote:

On Mar 5, 12:35 pm, "derdag" <der...@xxxxxxxxxxxxxxxxxxxx> wrote:
On Mar 5, 5:46 am, "SJAB1958" <balf...@xxxxxxxxxxx> wrote:

Can anyone help me out with a query? I know that the swapping of
genetic material between organisms arose before the formation of
separate genders, but did separate genders come before
hermaphrodites
or was it the other way round? Any website links that would help
here
would be greatly appreciated.

When evolution decided ...

"Evolution" does not 'decide' anything. That would be ignorant
anthorpomorphism. Unlike our dear Prez, evolution is not the
'decider' of anything. Local environmental conditions, OTOH, are the
the dumb, unintelligent decider between variants based on how well
those variants reproduce.
<snip>

When normal people say that evolution "decides" or "chooses", it is
simple anthropomorhic shorthand, a common practice among the
cognoscenti. When derdag says it, it is plain ignorance, not
specifically anthropomorphic ignorance.

And, lest derdag think we are picking on him, notice that he did
write: 'A couple of them had the same idea at the same time.' A couple
of what? A couple of species? No evidence that it would have been
at the same time. A couple of individuals? Individuals don't 'decide'
in any sense in the ToE.

How about suicide?

Well, OK. Or the decision to have a large family. Or the decision to
migrate. Individual decisions can influence the direction in which
population gene frequencies go. However, they cannot result in heritable
genetic mutations.

Well, OK. The decision to become a worker in a nuclear plant or an
airline pilot. But individuals in a population of asexual reproducers
don't 'decide' to reproduce sexually instead and pass that trait on to
their children. Which is what I think derdag was suggesting.- Hide quoted text -

- Show quoted text -

derdag did suggest that there was a problem at the time some and I
mean (one) cell underwent meosis instead of mitosis, needing a proper
(irreducibly complex) structure present for combining with another
haploid cell (and there must have been only (one other one) to become
a diploid cell. It could do it several times and there would still
only be one cell. God Bless you for putting up with this stupidity.
lol I realize that if this occured in a sex cell of a multicelled
organism, that the problem would be somewhat less complex in that
way. However, if that were the case we would need two organisms to
develope the lock and key mechanism and find eachother.

Lets just assume that the other poster is right and that mitosis
became meosis in a single celled organism. The other problems are
even more complex. (1+1) becomes (1) and (1); and then (1) and (1)
combine to become (1+1) again.

Man, that works out pretty sweet.

Actually, I would envision early eucaryotes as having something akin
to the macronucleus of Tetrahymena. This large nucleus contains
*many* copies of each gene and does not divide by mitosis. Rather it
simply splits in two and relies on chance to ensure that, most of the
time, both nuclei have all the required genes it needs. Mitosis,
then, is a mechanism that *regularizes* the distribution of genes in a
nuclear division. Such a process becomes more useful as the number of
'genes' (not copies of genes) becomes larger, thus increasing the
chance that mere nuclear fission will produce a 'defective' nucleus
missing some useful gene. One way of restoring function and of
gaining novel functions that other organisms have developed is to
undergo genomic fusion. The *initial* steps in developing a system of
regularizing the distribution of genetic information between daughter
cells (the process, once perfected, we call mitosis) need not be
perfect, merely better at producing surviving daughter cells than
simple fission of nuclei that have reached a certain size.

Meiosis, then, is merely a way to regularize the reduction of nuclear
size and genomic complexity that occurs as a result of nuclear
fusions. Initially, I would suspect that it was not designed to go
from a diploid genome to a haploid one, but from an n-ploid (with n
being fairly large, but not necessarily even) to a roughly 1/2 n-ploid
state. In organisms where efficiency wrt the size of the genome
matters (think unicellular in competition with bacteria), the n-ploid
state is inefficient, and improvements and regularization in the
efficiency of mitosis, meiosis, and cell fusion would allow cells to
be more efficient. Eucaryotic sex involving diploid to haploid
followed by fusion, then, is the *end result* of a process of becoming
more efficient, not a magical poofing into existence.- Hide quoted text -

- Show quoted text -


.

Relevant Pages

  • Re: Evolution of Separate Genders in Animals
    ... mean cell underwent meosis instead of mitosis, ... if that were the case we would need two organisms to ... Lets just assume that the other poster is right and that mitosis ... both nuclei have all the required genes it needs. ...
    (talk.origins)
  • Re: Evolution of Separate Genders in Animals
    ... mean cell underwent meosis instead of mitosis, ... if that were the case we would need two organisms to ... Meiosis is more complicated than you seem to think. ...
    (talk.origins)
  • Re: Evolution of Separate Genders in Animals
    ... mean cell underwent meosis instead of mitosis, ... if that were the case we would need two organisms to ... Meiosis is more complicated than you seem to think. ...
    (talk.origins)
  • Re: Evolution of Separate Genders in Animals
    ... separate genders, but did separate genders come before ... mean cell underwent meosis instead of mitosis, ... if that were the case we would need two organisms to ... for crossing-over during meiosis. ...
    (talk.origins)
  • Re: new creationist argument? cortical inheritance
    ... Dr Jones moves onto the subject of DNA and Inheritance. ... some part of the membrane of cellular organisms. ... This must be universal to all cells, not just ciliates, because the ... Each new cell gets half the ...
    (talk.origins)