Unformatted text preview: eloped a strain of turkeys whose eggs developed without fertilization about 40 percent of the
time. No one expected that animals as complex and modern as turkeys
could so easily be pushed into a single-sex way of life. By the criteria of
sheer mass and numbers, most of these animals are much more successful than we are. So why do so many animals and so many plants devote
so much time and energy to sex? Put most simply, we don’t know. No
one has ever unequivocally established why we have sex instead of just
splitting in two every once in a while like bacteria.
The Selfish Gene and the Red Queen
The explanation of the purpose of sex offered most frequently is a theory
called the “Red Queen” hypothesis, which is a simple corollary of the
“selfish gene” hypothesis first proposed by Richard Dawkins.1 Dawkins’s
hypothesis suggests that humans, as well as plants and other animals,
are no more than containers built by evolution to move genes from
place to place and to deliver those genes into spaces where they can
make more copies of themselves.
At first that might seem absurd, but it has some merit. Imagine
the beginnings of life in the warm seas of Earth. As the camera pans
back, we see steamy seas surrounded by nothing but bare rock, some
of it still molten. This is a bleak place and will remain so for billions
of years. The camera then zooms in on the seawater and slips beneath
the surface. Here the picture is only slightly different—a few dissolved
chemicals and a lot more rock. But as we watch, a few of the chemicals
snap themselves together like pop-beads and make long strings of mol- Sex Versus Reproduction 37 ecules like DNA, molecules that look a little like genes. Once the pieces
have strung themselves together, they acquire a most remarkable ability: from pieces floating in the nearby sea water these long molecules
can make more like themselves, or very nearly like themselves. They
Abruptly, this chemical reaction spreads across the Earth’s seas.
Molecules are zipping themselves up everywhere, until only a few free
pieces still float in the open water. Then, only the fastest of the big
molecules can make more like themselves. The fastest molecules soon
outrace the slower ones and dominate the early seas. But the raw materials continue to dwindle until even the fastest of these pre-genes have
trouble making more copies of themselves. For a while, things nearly
stop. Then one newly assembled large molecule discovers it can disassemble other large molecules and use the recycled materials for its own
The process all starts over again, with the whole molecular world
ripping away at itself until one molecule figures out how to wrap itself
in an oil droplet to protect itself from the surrounding destruction.
At that instant, the first cell is born. And all the rest spirals out from
there—archaea, bacteria, plants, jellyfish, fish, lizards, humans—all
simply more and more diverse vessels for the genes, vessels driven by
genes, to protect genes, to transport genes, and to deliver genes into
places where they can, just as they have for billions of years, make more
copies of themselves. Selfish genes.
From time beyond recollection, genes have run everything. And,
at least according to Dawkins, every act a human being has ever performed was dictated by one of those selfish genes. Writing poetry, for
The wind was a torrent of darkness upon the gusty trees,
The moon was a ghostly galleon tossed upon cloudy seas,
The road was a ribbon of moonlight looping the purple moor,
And the highwayman came riding—
from “The Highwayman” by Alfred Noyes, 1907 38 Between XX and XY Alfred Noyes may have seen his composition as a simple act of love
for words and sounds, a little lust for the lyrical. To Richard Dawkins,
though, Noyes was merely the pawn of his selfish genes, which manipulated Noyes for their own ends—reproduction. Noyes’s intellectual
intentions had nothing to do with the outcome of his work; his genes
were just hoping to get him laid. Later that same year, Noyes married
Garnett Daniels. Over the next few years, they had three children. And
in 1925, Noyes converted to Catholicism, a calling known for its reproductive prowess.
Hard to argue with that—Alfred and Garnett and their visions of
ghostly galleons, Richard Dawkins and his selfish genes—a DNA-driven
plot to make more DNA. Better poetry through chemistry. The seductive selfish gene.
But if the selfish-gene theory is true, why bother with Alfred at all?
Ms. Daniels, all on her own, could have produced many more children
in the same amount of time had she been capable of parthenogenesis—asexual reproduction. If she could have done that, all the energy
that Alfred poured into his poetry, all the food he consumed, the fires
he burned, and the spaces he occupied would have been available to
Ms. Daniels for making more women, who would make more women,
and so on. Not only that, the fact remains that life forms that write terrible poetry (bacteria) and w...
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This document was uploaded on 02/04/2014.
- Spring '14