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/sci/ - Science & Math

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8327712 No.8327712 [Reply] [Original]

>mfw I realize that sexual reproduction evolved only once (1ce) in ~3.7 billion (3,700,000,000) years of life.

Holy moly! Does this mean sex was a fluke? If we meet aliums, will they be asexual, or will they not exist because sex is a pre-req for long-term multicellular evolution? For that matter, is multicellularity a fluke? Is life in general a fluke? Are flukes asexual?

>> No.8327720

>>8327712
Plants evolved sexual reproduction too.
And bacteria don't need sexual reproduction since they can exchange genetic information directly.

So that's two cases of sexual reproduction evolving, and one case of something similarly effective evolving.

>> No.8327730

>>8327720
>Plants evolved sexual reproduction too.
I thought so too but then I was watching a lecture and the professor said that it's now believed that plants, fungi (which can also reproduce sexually), animals, and various sexually-reproducing protists all descend from a common ancestor that had specialized mating types.

From wikipedia:
>Many protists reproduce sexually, as do the multicellular plants, animals, and fungi. In the eukaryotic fossil record, sexual reproduction first appeared by 1.2 billion years ago in the Proterozoic Eon.[59] All sexually reproducing eukaryotic organisms derive from a single-celled common ancestor.[1][51][60][61]

>> No.8327731

alll.you.girls.safety.counts

>> No.8327743

>>8327712
Isn't sexual reproduction actually pretty inefficient? With each child, half the total genetic information doesn't get passed on, so it's a pretty big gamble and a huge slog to fix good mutations. Why don't we just reproduce parthenogenically and exchange DNA directly, like bacteria? Doesn't seem too difficult to implement (e.g. bringing reproductive organs together and exchanging ova).
Is it really that advantageous to discard 50% from each parent? If only a limited number of genes were to be exchanged, then good mutations would be pretty much fixed by default.

>> No.8327755

>>8327743
Sexual reproduction is inefficient but it's a safer bet in the long run. In multi-cellular organisms that revert to asexuality, the population eventually accumulates mutational load due to a phenomenon known as Muller's Ratchet. Eventually they accumulate too much mutational load and they go extinct. The only seeming exception to this are the Bdelloid rotifers, which reverted to asexuality ~25 MYA and are still going strong.

>> No.8327775

HOW CAN SINGLE CELLED ORGANISMS EVEN COMPETE?

>> No.8329082

>>8327712

my nigga, sexual reproduction is not a pre-req for multicellular life. im not sure why you think that.

however the two-fold cost of meiosis is a trade off, there are not absolutes; under some conditions asexual reproduction is a godsend. under others it means you dont get the genetic diversity needed to withstand future conditions.

sexual reproduction was as much a fluke as it was an inevitability. some kind of genetic recombination had to exist in order to colonize a dynamic environment.

>> No.8329084

>>8329082
If it wasn't a fluke and was truly inevitable you'd expect it to evolve more than once, like wings or fins.

>> No.8329087

>>8327755

also medwars theory anon