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Unformatted text preview: ho know nothing about either sex or death
remain the most successful of all living things on this planet.
So the question remains. Why do so many of us devote so much
time and energy to sexual interaction?
In Lewis Carroll’s Through the Looking Glass and What Alice Found
There, Alice finds herself racing across a giant chessboard with the Red
Queen. After a bit, Alice notices that even though she and the Queen
are running as fast as they possibly can, everything around them is
stationary. The trees, the flowers, the checkerboard—all appear to be
standing still. The Queen finally tells Alice she can rest a while and
props her against a tree. As Alice recovers her breath, she notices that
this is the same tree where it all began. Speaking to the Queen, Alice
says, “Why, I do believe we’ve been under this tree for the whole time!
Everything is just as it was!” Sex Versus Reproduction 39 To which the Red Queen replies, “Of course it is. What would you
“Well, in our country,” says Alice, “you’d generally get to somewhere
else—if you run very fast for a long time, as we’ve been doing.”
“A slow sort of country!” says the Queen. “Now, here, you see, it
takes all the running you can do, to keep in the same place. If you want
to get somewhere else, you must run at least twice as fast as that!”
Our world is much like the world of the Red Queen. Every day of
our lives, there are at least ten billion other living things that would like
to eat us for lunch and claim the space that we currently occupy. The
same is true for every other animal and plant on Earth. The proof of that
appears whenever our defenses drop, for example, when an HIV infection strips one of us of an immune system and raises that thin curtain
that stands between us and the rest of the world.
Then, in a relatively short period of time, where an individual had
just stood, there is suddenly a community of living things—bacteria,
viruses, fungi, and parasites. We exist only so long as we can defend
our claims to our individuality and a small piece of the planet. Life is
hard and tenuous.
To make matters even worse, our competitors—the microbes—
never stand still. Every time our immune systems conjure up a new
way to save us from one of them, the microbes come up with a new
diversion of their own, a new way of fooling our defenses and slipping
into our blood, or our brains, or our livers. The Red Queen hypothesis
proposes that the only thing that saves us from this horrible fate is sex.
Bacteria divide once every twenty minutes or so, and at every division there is the opportunity for genetic change. In humans, it takes
roughly twenty years. Clearly, bacteria evolve much faster than humans
do. So our immune systems are always shooting at moving targets.
Because of that, we must, as Alice and the Red Queen did, run as fast
as we can just to stay in place. We must evolve as quickly as possible just to stay alive. If we didn’t do that—if we didn’t continuously
reshuffle our genetic decks—human diversity would stagnate. If that
happened, when one bacterium finally figured out a way around one
human immune system, that bacterium might be able to get around all 40 Between XX and XY human immune systems. Then, if an infectious disease killed one man
or woman, it might just as easily kill all of us.
The Red Queen theory says that our salvation is reproduction—
the mixing of the genes that occurs every time sperm and ovum come
together to start a new life. The more often we shuffle our genetic deck
and deal ourselves new hands, the less likely it is that any microbial
body will guess just which hand it must play to beat us. Without sex,
our similarities would kill us.
The Red Queen theory seems sensible, but two rather large problems still remain. First, if sex is so critical to survival, why do we still
have sponges and starfish and worms and insects and turkeys? It’s not
like these animals are struggling to make it; they outnumber us dramatically (except for turkeys). Then there are also all of those asexually
reproducing plants that are doing just fine out there, thank you. Second,
as discussed earlier, human sex seems in no particular way to focus on
the act of reproduction. People have sex all of the time. What is that
Clearly reproduction requires sex. But maybe that is only one of
many functions of this wondrous act. Is it possible that our views about
sexuality and reproduction are merely a consequence of how we are
brought up, the things we are taught to believe, an impact crater left by
a religious meteorite? One way to answer that question is to take a look
at our closest living relatives—relatives not burdened with our traditions, our mythologies, or our guilt, and see if they share our attitudes
Bonobos at Play
Because of our fascination with sex and our hubris about being the
pinnacle of evolution, we have come to regard human sex as something
sacred and unlike anything found elsewhere in the animal kingdom.
In his landmark b...
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This document was uploaded on 02/04/2014.
- Spring '14