So the other day I was reading around on the Internet and I found this amazing exchange:
OK, so this is probably not as scintillating a question as the topic heading suggests.
I’ve heard a few biologists – Prof. Dawkins included – state that one of the big remaining questions in their field is why so many species reproduce sexually, and what the advantages are. I’ve read a few theories on the subject – that beneficial mutations can be expressed more strongly and therefore more benefit their own survival through sexual reproduction than through asexual reproduction, that it can help weed out rubbish genes, that it can protect the species from parasites etc – but what I can’t get a feel for is whether this question is one of the “genuine unknowns” that are still wide open, or whether the top boffs basically know the answer/s but are arguing over the fine detail.
Can anyone enlighten me on this one?
(SoggyMoggy@ The Richard Dawkins Foundation for Reason and Science)
Now the first answer to this question is from Richard Dawkins himself:
Here’s a brief reading list, beginning with the seminal books that started the modern effort to understand the natural selection of sex.
G C Williams (1975) Sex and Evolution
J Maynard Smith (1978) The Evolution of Sex
G Bell (1982) The Masterpiece of Nature
W D Hamilton devoted much of the latter part of his career to the question. You can read his papers in the later volumes of Narrow Roads of Gene Land, and there is a good popular account in Matt Ridley’s (1995) The Red Queen. Rick Michod’s rather different book is Eros and Evolution.
The Wikipedia article on ‘Evolution of sexual reproduction’ is quite good.
(Richard Dawkins @ The Richard Dawkins Foundation for Reason and Science)
To me this is an absolutely fascinating response from the worlds most vocal proponent of atheism and evolution. Why? Because I believe that sexual reproduction represents one of the strongest pieces of evidence for the God of the Bible. The simple fact of the matter is that Darwin’s theory predicts that biological organisms should reproduce asexually. The fact that they reproduce sexually is one of the greatest mysteries in biology and, while many hypotheses have been offered, no general explanation has been found satisfactory enough to consider the problem closed. This is why Richard Dawkins has to answer the simple question of how to understand sexual reproduction by suggesting almost one thousand pages of reading that describes the different theories.
Biblical creation, on the other hand, explains sexual reproduction easily and simply. This is because the reason that sexual reproduction is such a big mystery to biologists is that it slows down the rate of evolution enormously. If evolution is responsible for eyes and ears and the examples of what Richard Dawkins calls “apparent design”, why would you want to slow this process down? On the other hand, if biological organisms were created perfect by God and random mutation is a destructive process, then slowing evolution down slows down the destruction caused by random mutation and gives species greater fitness in a geological time frame. (This effect is called Muller’s Ratchet in the scientific journals.)
The bottom line is that Darwin’s Theory predicts that organisms should reproduce asexually and having a theory of life that predicts that living organisms should reproduce asexually is like having a theory of gravity that predicts that we should all float off into space.
A coworker read this post and pointed out that evolution does not have a hard time explaining the persistence of sex, merely its origin. He wrote a quick simulation of sexual verses asexual reproduction that demonstrated the Muller’s Ratchet effect and seemed to show that sexual reproduction was more effective at propagating favourable mutations. Regardless, the origin of sexual reproduction is tremendously difficult to explain from an evolutionary perspective as described by Graham Bell in his book, The Masterpiece of Nature: The Evolution of Genetics and Sexuality:
Sex is the queen of problems in evolutionary biology. Perhaps no other natural phenomenon has aroused so much interest; certainly none has sowed as much confusion. The insights of Darwin and Mendel, which have illuminated so many mysteries, have so far failed to shed more than a dim and wavering light on the central mystery of sexuality, emphasizing its obscurity by its very isolation.