Posted by: zyxo | July 15, 2008

Are men and women different species ?

The missionary position of human sexual interc...Image via WikipediaSometimes I see that people arrive on my blog by typing the above question in a search engine.
Are men and women different species ?

First of all : what is a species? This is not so simple. According to wikipedia, a species is “a group of organisms capable of interbreeding and producing fertile offspring“. It is clear that this definition only holds for organisms which reproduce sexually. For the others, there are apparently other words.
Moreover, in an interesting paper, Ernst Mayr points out that a species is not just a man-made unit of classification of animals, but a concrete phenomenon of nature : a species is “… principal unit of evolution and it is impossible to write about evolution, and indeed about almost any aspect of the philosophy of biology, without having a sound understanding of the meaning of biological species“.

The fact that men and women can have fertile children make them one and the same species. No doubt about it.

And what about all the differences between them ? This is nothing special in the animal world. Look at the birds : a lot of species have dull-coloured females and brightly coloured males.
The praying mantid female is much bigger than the male, she even bites his head off right before copulation !

But what if with all the technology, women will not require a man any more to have children ? No big deal. It is not because they do not interbreed that they can not ! If John has no relation whatsoever with Mary and consequently they do not have any children together, does that mean that they are different species? No, it is not that because they do not that they can not !

Did you enjoy this post ? Then you might be interested by the following :
Human procreation strategies
are men and women different ?
Imbalance of cheating

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  1. Sexual reproduction isn’t a given. Just when in our evolution history we picked up this quoit trait is still to be determined, why we kept it doesn’t make sense. Asexual reproduction is by far more economical.

    Why we use sexual reproduction as a defining attribute for a species seems arbitrary at best. Its just another evolutionary trait.

    Much more relevant would be how well do organisms communicate between members of the group. Organisms that communicate well together would belong to the same species.

    Do they look alike? Do they eat salads or meats? Do they have the same basic needs?This list of relevant attributes can go on and on.

  2. Val,
    1. I think “we” picked up sexual reproduction way before there was “we”. It seems as it only appeared once and thereafter was the source of all sexual reproducing species.
    2. Asexual reproduction is more economical, but the sexual reproduction and the “manipulation” of chromosomes it uses makes way for things like crossing-overs which are a mechanism of evolution much faster then mutation.
    3. I do not agree with you for the arbitrary definition of species. I think E.Mayr has a point with his “… principal unit of evolution” (with or without sexual reproduction).
    4. Communication as a relevant attribute for determining of two individuals belong to the same species ? Howmany people would’nt be dogs in stead of humans ? 🙂

  3. Two males cannot reproduce so does that mean that any two males don’t belong to the same species?

    • Hi Harshit, thanks for visiting my blog.
      Sharp reasoning by the way.
      But look at it the following way: if male A can reproduce with female X, A and X are the same species. And if male B can reproduce with female X, then X and B are the same species.
      Conclusion: A and B are the same species, right?

  4. Totally false. A homogenous gene pool cannot diverge into morphs. Therefore no species ever diverged into male and female morphs. Instead two different species came together in cooperation and after a lot of time spent evolving with each other came to be able to swap genes before reproduction. Male and female are two species that evolved to work together

  5. Males and females are of same species but can be considered to be from two separate “subspecies”.

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