Wednesday, December 20, 2006

Philadelphia Inquirer Tackles How We Evolved Into Male and Female

It's actually a very well done article. And I suspect it is good because the author was being honest from a Darwinian perspective, without considering the implication with regards to Intelligent Design.
The first sexual beings to emerge perhaps 2.5 billion years ago were what biologists call isogamous - which is a little like being gay, except everyone is somewhere between male and female.

Many organisms, including some fungi, algae and single-celled pond-swimmers, still practice isogamy. In doing so they offer clues to the mystery of why and how the sexes ever evolved.

To understand life before the advent of males and females, you need a universal definition of each: Males produce a smaller sex cell (sperm or pollen) than their female counterparts.

Isogamous algae, on the other hand, still have sex but instead of mixing sperm and eggs they mingle sex cells of roughly the same size - generically known as gametes.

Good summary.
What scientists find puzzling is that most of them still use a system of two sexes - in their case plus and minus rather than male and female. Though plus and minus create the equal-sized sex cells, plus mates only with minus and minus with plus.

Such pickiness is an enormous paradox, says Laurence Hurst, a biologist at the University of Bath. Without sexes, you wouldn't have to limit your choice of a mate to half the population. Anyone else would be fair game.

Well that be a paradox, but I see another problem. I'll just print out the email I sent the author and then try to clarify what is bouncing around in my head:
I thought your article was very good.

However, there is a bigger problem you should have gone over (maybe for a later article): how sexual reproduction (of any type) gets off the ground in the first place.

Assume you start with reproduction by self-replication. If that's the starting point, the finish line is some sort of sexual reproduction that involves two cells creating another cell.

You start with one becoming two and you go to two forming one. I don't see how the steps in between can work.

Not only is the flow reversed, but for reproduction to work you need two mutually compatible organisms to arise at the same time.

If you can make this the subject of an article, I would appreciate it.

I am not a biologist, but I do build software for a living. I just don't see a bridge between a program copying itself and two separate executables creating one new executable program.

Does that make sense? That's a chasm that no step-by-step bridge can cross.

But if you are willing to give it a shot, feel free to leave a comment.

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If you start by viewing as software, of course you're going to conclude it's intelligently designed (because software is).

Aside from that, there are plenty of intermediates. Bacteria exchange genetic information on plasmids for their mutual benefit. Earthworms are hemaphrotitic. Some animals can self-fertilize in the absense of a male.

IMO, the development of sex is far less difficult to imagine than the origins of the genetic code or self-replication.
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