Why would sexual reproduction ever have evolved?

Question

If everything evolved from a simple single celled organism that reproduced asexually (dividing) how would evolution ever favor something that had much worse odds of ever happening like sexual reproduction? How would that ability have evolved? How could it even have started --- what are the chances that 2 (not just 1) of these single celled organisms simultaneously mutated and developed the ability to reproduce sexually? And even if they did -- why would the trait be favored? -- it seems that within the first few generations the offspring would have found some difficulty in finding one another or successfully mating -- and eventually die out. How could it have happened by chance?

Answer 1

My heart is searching for love. I'm the kind of person who is always spacing, or listening to music [sometimes even slow music like Sade Lover's Rock, like right now], or always kind of out there or something. I'm the kind of person who really just wants someone to be in love with. The kind of person who can't survive without love

Answer 2

There are many existing examples of single-celled organisms that exchange genetic material before dividing asexually. The advantage is that this becomes an alternative (and more dependable) source of new genetic material that the only other method available ... mutation.

Also, note that it does not require two dedicated "sexes" (as we have) ... so it is not true that 2 (not just 1) of these single-celled organisms had to mutate simultaneously. All of the organisms both deliver and receive this exchange of genetic material.

Dedicated sexes came *much* later, and again there are many examples in nature of various gradations of sexual "specialization" ... from organisms (like most flowering plants) in which all individuals have both sex organs, to organisms that go through "male" and "female" phases at different stages in development, to organisms that can reproduce both sexually and asexually (like aphids), to organisms where dedicated sexes are determined after birth (like bees). We are just most familiar with the "specialized sexes" system because it is the system used by humans, mammals, and most other vertebrates (but not all).

> "How could it have happened by chance?"

Just like all evolution, it did NOT happen by chance. Natural selection causes slight advantages to propagate ... and this is NOT a random process.

Answer 3

a single celled organism that reproduces asexually evolves the ability to reproduce sexually, it can still probably reproduce asexually and so it does. Then you have 2 cells that can reproduce sexually or asexually. The 2 cells and their lineages will independently mutate and reproduce by either mean. The genetic diversity of the offspring of the 2 will be favorable to survival.

Answer 4

single celled organisms can reproduce both through sexual and asexual reproduction. sexual reproduction allows variety among the offsprings which increases their chance of survival in the constantly changing environment.

as to the evolution of sexual reproduction, some researchers believe that these single celled organisms just instinctively exchanged their genetic material with each other for the continuation of their "species" (although this method gave way to the production of different species of single celled organisms).

Answer 5

Primitive life forms did reproduce asexually, but they also absorbed genetic material from other like organisms.

Very likely, sexual reproduction evolved as a continutation of bacteria "eating" or absorbing genes from other bacteria.

Answer 6

Mix and match evolves much faster than playing the same dead hand every time. Compare evolutionary algoritms to Wincrap for adaptively getting the job done.

Answer 7

Generally, hybrids are healthier and stronger. They only way to get a hybrid is through the joining of two different sets of DNA.

Answer 8

The diversity obtained became a major survival factor. ~

Answer 9

you know some bacteria reproduce sexually?

Answer 10

I know, I heard.