Originally posted by Wumpus
……At what point did sexual reproduction evolve? ..…
As a Christian (and one with an open mind), I find it very difficult to take the Genesis account literally, word-for-word. My understanding is that the 7-day account is the author’s experience as God showed him in a vision or a dream how everything was created (why does an almighty god need to rest on the 7th day anyway. It makes far more sense to me that H ...[text shortened]... another human to reproduce)? A virus is a far more “fitter” organism than we humans are anyway.
knowbody knows for sure but there are plenty of theories.
But it is generally thought that it probably didn’t evolve until more advances cells evolved than simple bacterial cells -that would mean that for most of the history of life on Earth (about ¾ of it) there was no sexual reproduction which implies that the evolutionary step from asexual reproduction to sexual reproduction was a difficult one.
…This would require two organisms (regardless of complexity) to evolve sexual reproductive organs at EXACTLY the same time. ..…
It would just requires ONE organism (say a single cell of an amoeba-like organism) to mutate so that, although it still maintains the ability for asexual reproduction (probably through the usual simple cell division) it has the potential
of sexual reproduction (by exchanging genes -but not necessarily involving meiosis -a simpler form of gene exchange may have evolved first) of another organism of the SAME species that carries the SAME mutation. That would mean that, initially, it would only be able to reproduce asexually but then its offspring would be able to reproduce sexually with each other. Note that would mean that the mutation wouldn’t give any immediate
benefit to the organism which is why this evolutionary step was probably a difficult one.
There are many living example of organisms that can reproduce sexually AND asexually but will always reproduce asexually if there is no current opportunity to reproduce sexually (e.g. strawberry plants).
Also note that the first organisms that could reproduce sexually probably didn’t consist of separate male and female individuals but, rather, consisted only of individuals that where both male and female as this is more likely to evolve first if the sexual reproduction consists of only the simplest possible kind of gene exchange.
There are many living example of organisms that consisted only of individuals that are both male and female -Earthworms are a good example.
Separate male individuals and female individuals probably evolved later.
…Furthermore, why would a virus (that simply splits to reproduce) ...…
Err -A virus does not “split” to reproduce. A virus first enters a host cell and then releases its genes into the host cell (and OUTSIDE the virus) which then express themselves by creating new virus particles outside
from the original virus particle that entered that cell.
A virus that has “split” is generally a dead virus!
…ever WANT to evolve in a human to begin with (that needs to seek out another human to reproduce)?
-ever “WANT ” to evolve in a human?
-nothing evolves anywhere it does or to do anything it does because it “WANTS” to.
It evolves in a human being because some virus particles by chance ended up in a human and mutations and then natural selection made it evolved.