Re: First life form on earth

Guy Hoelzer <[EMAIL PROTECTED]> wrote:

> in article [EMAIL PROTECTED], Red Dragon at
> [EMAIL PROTECTED] wrote on 11/20/03 8:53 AM:
> 
> > Does anybody  know the first life form on earth,
> 
> Not precisely.
> 
> > was it a plant or an animal
> > in Charles Darwin 's origin of Species?
> 
> Darwin did not address this issue, but there is no question that the first
> organism was neither a plant nor an animal.  It took billions of years of
> evolution before either plants or animals arose.  The first organism would
> clearly have been a single-celled, bacterium-like beast.

Darwin suggested that in a still warm pond filled with salts, life would
arise. I am sure he would not have tried to make it either a plant or an
animal - knowing better.
> 
> > I am inclined to think it is a plant
> > and  I read from somewhere that it was   green algae.   But  I also came
> > across somewhere that it was  sponges.   That leads to the next question
> > namely,  how did the plant become an animal?
> 
> You knowledge base must not include much about evolutionary biology to think
> that the first organism could have been anything like a plant or animal
> (including sponges).  The notion that it could have been a multicellular
> animal, like a sponge, is inconsistent with all the information we have on
> the subject.
> 
> Note that the evidence is pretty clear that animals did not evolve from
> plants, or vice versa.  I am not sure what you are asking when you write
> "how did the plant become an animal?", but changes of this sort are
> generally called evolution.  Taxa evolve and become different than their
> ancestors.
> 
Plants are eukaryotes (like animals) and these formed rather late from
the merging of an algal cell with a prokaryotic cell. Plants evolved, I
believe, *after* animal and fungal cells. After all this happened,
multicellular organisms evolved.
-- 
John Wilkins wilkins.id.au
For long you live and high you fly, 
and smiles you'll give and tears you'll cry
and all you touch and all you see is all your life will ever be