By Carl Zimmer | June 4, 2009 5:01 pm

ladybugs.jpg“We do not even in the least know the final cause of sexuality; why new beings should be produced by the union of the two sexual elements…The whole subject is as yet hidden in darkness.”

So wrote Charles Darwin in 1862. In this week’s issue of Science, I write an essay on what we know now about this mystery. The essay is here (subscription required), and you can listen to me talking about why sex is weirder than you know on this week’s Science Podcast.

To continue this celebration of sex in all its evolutionary glory, I’ll be guest-blogging a few times this month over at Science‘s Origins blog. I’ll let you know here when each post goes up.

Image: From Robert F. on Flickr/Creative Commons Licence

CATEGORIZED UNDER: Evolution, Writing Elsewhere

Comments (8)

  1. That’s some pretty vanilla ladybird sex going on right there. Perhaps “light will be shed” on the mystery of trans-species threesomes too?

  2. Barry Roth

    My favorite variation is the Polygyrid snail with a “female penis” that GOES IN AND GETS the sperm! How about that now, R. A. Fisher?

  3. As it happens, this week The American Naturalist has a special issue all about “The Evolution Of Sex: Recent Resolutions And Remaining Riddles”. Pretty sweet.

  4. Rob

    Vanilla ladybird sex it may be, Neil, but the perps are Harmonia axyridis, the most evil ladybird species on the planet, currently tearing through the natural ladybird community in my back garden after invading the UK a couple of years ago…

    Back on subject the American Naturalist has got a supplement just out on the evolution of sex and recombination as well: for those who can access it.

  5. How did sex ever come into play with evolution? Why would it have been beneficial instead of cell division? Do you think that evolution could bring two different cells through different mutations together that would be able to mate together creating a female and male gender? What are the chances of that? I don’t understand why mating would be beneficial when cells can just divide and multiply.

  6. Norman Stone

    Looking for an early pathway toward sexual reproduction. Think about it…

    1. Multi-celled organisms can’t simply split; at some point of complexity ovulation or gestation becomes inevitable.
    a. So, should all members of a species be required to gestate? Not if I can help it!
    b. And yet, let’s face it, if I can’t get my genes reproduced, what I want will soon cease to matter.
    c. So let’s make a deal: I will go out and take the risks and kill (for) the food; you can stay at the protected site and have our kids.
    2. OK, the strategy makes sense. But that doesn’t guarantee an efficient evolutionary pathway to the strategy, so let’s look for one.
    a. Thinking outloud now. Have we ever sufficiently answered the question,”when is bigger better?”? Many answers emerge, including:”when a longer life span can take advantage of certain longer natural cycles (such as the higher tides of a lunar cycle, the year obviously, etc.)” In other words, size by itself might not be the advantage — it may be a means to the end of reaching certain “top shelf” resources.
    b. So size may actually be an intrinsic disadvantage balanced out by massive extrinsic advantages. We like this idea for the following reason: it is likely that over-the-top variations can be improved by reverting back toward an earlier form. When a powerful resource comes within reach through a relatively unsophisticated variation, the vectors that draw the variations toward that resource often lead to exaggerated variations, and the pathways back toward moderation are rich with potential for success.
    c. So within this scenario, we can hypothesize such “oversize-variations” as those in which gestation first emerges as a “mini-me”, possibly capable of shedding the aging outer shell. At the same time, another “oversize-variation” could include something like siamese twins, capable of playing with division-of-labor variations (we are talking about worms or flagellates or something equally primitive), and equally capable of trading genetic packages. In reversion back to a more moderate size, separation of the sexes could emerge.
    3. Not arguing that any of this is true — just imagining the possible.

  7. Jim from Male Enhancement Tips

    Hi Carl,

    Personally I have my own opinion I strongly believe you will disagree with: God created male and female – either humans, animals and plants. Multiplication was one of the major divine abilities God endowed living creatures with…

    This is what I eternally chosen to believe! I really don’t like to dabble into evolution as much as you shown here.

    However, the subject of sex and sexuality in humans, no doubt, is deep and somehow mysterious. This is a major reason I set up the male enhancement site.

    Take orgasm for example, it has continue to baffle men for centuries, especially as it happens to women.

    [CZ: I just had to allow this spam comment through…after I deleted the link to Jim’s male enhancement web site.]


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The Loom

A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer.

About Carl Zimmer

Carl Zimmer writes about science regularly for The New York Times and magazines such as DISCOVER, which also hosts his blog, The LoomHe is the author of 12 books, the most recent of which is Science Ink: Tattoos of the Science Obsessed.


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