Tuesday, November 3, 2009

Homosexuality: Was Darwin Wrong On Sexual Selection?

The article "The effeminate sheep and other problems with Darwinian sexual selection" by Jonah Lehrer was published in the June/July 2006 issue of SEED magazine. It's been circulating around the internet this past week after news broke that a high school teacher from Piasa, Illinois was suspended for giving his students this article to read as an optional class discussion. Soon, a Facebook group was created by students from Southwestern High School in support of their beloved teacher, Dan DeLong. The author of the article, Jonah Lehrer, also showed his support on his blog The Frontal Cortex. DeLong had since been given his job back after he publicly apologize for handing out an age inappropriate article. This whole outburst just screams homophobia to me. It is a disgrace to the country's education system because a thought provoking and queer-friendly curriculum resulted in someone being suspended. I bet none of the parents would even complain if their kids were given an article explaining the extinction of dinosaurs were due to them being late to Noah's ark.


Dinosaurs, Left Behind. Illustration from CartoonStock.

Anyway, back to the article. Joan Roughgarden, a Biology professor from Stanford University thinks that Darwin got it wrong about sexual selection. She also thinks that sexual theory is still stuck in the 19th century.


 Joan Roughgarden's book Evolution's Rainbow.


Two female bonobos having sex. Bonobos are fully bisexual, they don't really care which gender they are having sex with.

Sexual selection cannot explain homosexuality in over 450 different vertebrate species, said Roughgarden. Homosexuality, long thought to be deviant and serves no purpose biologically, is actually normal and a necessary fact of life.. Her book, Evolution's Rainbow, is an attack on Darwin's theory of sexual selection citing that the pervasiveness of homosexuality in the animal kingdom is actually adaptive and had not been weeded out by natural selection. She also said that homosexuality is a necessary side effect for getting along: a necessary feature of advanced animal communities that require communal bonds to function.


 Gay mallards Anas platyrhynchos. Photo from Wikipedia.

An example of this in the primate societies are the Japanese macaques (Macaca fuscata).

Japanese macaques, an old world primate, illustrate this principle perfectly. Macaque society revolves around females, who form intricate dominance hierarchies within a given group. Males are transient. To help maintain the necessary social networks, female macaques engage in rampant lesbianism. These friendly copulations, which can last up to four days, form the bedrock of macaque society, preventing unnecessary violence and aggression. Females that sleep together will even defend each other from the unwanted advances of male macaques. In fact, behavioral scientist Paul Vasey has found that females will choose to mate with another female, as opposed to a horny male, 92.5% of the time. While this lesbianism probably decreases reproductive success for macaques in the short term, in the long run it is clearly beneficial for the species, since it fosters social stability. “Same-sex sexuality is just another way of maintaining physical intimacy,” Roughgarden says. “It’s like grooming, except we have lots of pleasure neurons in our genitals. When animals exhibit homosexual behavior, they are just using their genitals for a socially significant purpose.

Read more about Jonah Lehrer's "The effeminate sheep and other problems with Darwinian sexual selection" here.



"And Tango Makes Three". A storybook based on the real story of Silo and Roy, two gay chinstrap penguins from Central Park.

I think homosexuality in primates is an interesting yet often times a taboo topic. There should be more studies on the effect of homosexuality in primate societies. Are there differences and similarities between primate and human societies when it comes to homosexuality? I also think its about time to regard homosexuality as adaptive as opposed to maladaptive and start coming up with research to see how societies benefit from homosexuality. We already have the "Grandmother Hypothesis" so what about the "Gay, Lesbian and Transgender Family Member Hypothesis"?


Actor Rosario Dawson and her gay uncle, Frank. Poster from PFLAG.

What struck a cord for me was Roughgarden's explanation of homosexuality, “Same-sex sexuality is just another way of maintaining physical intimacy ... It’s like grooming, except we have lots of pleasure neurons in our genitals. When animals exhibit homosexual behavior, they are just using their genitals for a socially significant purpose".

Reference:

Lehrer, J. 2006. The effeminate sheep and other problems with Darwinian sexual selection. SEED Retrieved November 3, 2009, from http://seedmagazine.com/content/article/the_gay_animal_kingdom/

3 comments:

zacharoo said...

Interesting topics. I don't know the arguments at all, but I don't think sexual selection has to be invoked (or necessarily criticized) when it comes to homosexuality. Whatever happened to the null hypothesis of neutrality--perhaps homosexuality is neither adaptive nor maladaptive?

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Sheri said...

I came across this blog when I searched for "grandmother hypothesis and homosexuality". It seems obvious to me that there is a long term benefit to having homosexual people in the population. If some members of the family are not reproducing on their own, they are in a position to help raise children that already exist by providing time and resources that would otherwise be spread out among more children. This gives a clear advantage to any gene pool that has homosexual members, not in terms of number of offspring but in terms of how many of those offspring reach maturity and then reproduce on their own. If families with gay relatives outbreed families without gay relatives over time, natural selection will favour those families that carry genes for homosexuality. Homosexuality has historically had a positive effect on human reproduction, to the point that homosexuality in some members of the community is actually a BETTER genetic strategy than everyone being straight.