[_ Old Earth _] Asexual reproduction

[Bryce]

According to evolution, the first living thing to appear on this earth a few million years ago was a type of bacteria, correct?
It's known that Asexual reproduction is the primary form of reproduction for single-celled organisms such the archaea, bacteria, and protists. etc..

So my question is, Why did that change? And when? If the bacteria asexually reproduced and all things on this planet evolved from the bacteria, why aren't we all hermaphrodites or somthing of that sort?

The question may be silly, it just popped in my head randomly this morning.
Thanks in advance for any responses, and have a nice day. :roll:

 

[Barbarian]

According to evolution, the first living thing to appear on this earth a few million years ago was a type of bacteria, correct?

Yes.

It's known that Asexual reproduction is the primary form of reproduction for single-celled organisms such the archaea, bacteria, and protists. etc..

So my question is, Why did that change?

Selective advantage in many cases. If reproduction is entirely asexual, then the only evolution that can occur is by mutation, one at a time. On the other hand, if it's sexual, the entire population is a gene pool of slightly varying organisms, and recombination becomes a powerful and rapid source of variation for natural selection.

It should be noted that a form of this goes on with many bacteria. It is called "conjugation" and it does increase the response of a population to selective pressure.

And when?

Sometime in the first billion years. More elaborate forms than conjugation had to wait for eukaryotic cells.

If the bacteria asexually reproduced and all things on this planet evolved from the bacteria, why aren't we all hermaphrodites or somthing of that sort?

For most metazoans, the selective environment is active enough to make sexual reproduction more effective.

 

[Bryce]

Thanks, good answer; I was attempting to find a good explanation all day, figures this is the last place I check, lol.