Friday, April 2, 2010
Homosexuality in the animal kingdom
As Coyne describes on page 152-151, animals desperately desire to pass on their genetic information, which seems to be a large facet of evolution. Why then do certain animals of certain species ,such as black swans or amazon dolphins,display homosexual behavior if it does not yield any offspring?
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Some species may, like humans, engage in recreational sex - sex for the sake of having sex. Certain hormones may trigger a response in organisms (Campbell 46.5) such as the black swan or the amazon dolphin that they become sexually frustrated enough to simply go at it with whichever member of their species is at hand. Another possibility is that certain members of species may have certain characteristics that make them more desirable. Yet another is genetics - on page 228 Mr. Coyne quotes other scientific studies that suggest "homosexual males stayed home and helped their mothers produce other offspring," and these "'gayness' genes" were passed along by helping their brothers and sisters survive. Another possibility we could consider is that of emotional attachments. Interspecies bonds are not uncommon - we form friendships with our dogs, our cats, and all manner of pets. It's not that far of a leap within a species. Perhaps we underestimate the capacity of animal minds in looking for companionship - for example, the gay penguins in Central Park Zoo, Roy and Silo, who had no other available female penguins with which to mate.
ReplyDeleteSources:
Campbell
http://articles.sfgate.com/2004-02-07/news/17414549_1_bruce-bagemihl-homosexual-gay-penguins
http://cats.about.com/cs/felinehumanbond/a/bonding_bubba.htm?iam=metaresults&terms=shannon+swallow
I believe homosexual behavior can be argued to have a purpose in some animals and are sometimes simply a random mutation in genes that causes a change in sexual preference. In regards to black swans, homosexual males will either steal a nest or form a temporary threesome and then force the female out. However, this homosexual behavior most likely still exists because the homosexual males' capability of defending the eggs are much higher. This is somewhat an altruistic behavior in that these homosexual couples cannot reproduce themselves, so they protect the female's egg. In the case of Amazon dolphins, they tend to mate in groups without much regard to whether the dolphin is mating a male or a female, so this is more of a bisexual behavior. Homosexual behavior should not be able to be passed unless there is a purpose like for black swans because of the fact that this behavior is not possible to be passed on in generation. Without the some form of altruistic behavior demonstrated by homosexual couples like black swans, as Jerry Coyne states on page 248, this homosexual behavior will quickly die off. I can understand if bisexual behavior exists because it does not eliminate reproduction or survival. However, with mutation in genes occurring at random intervals, homosexual behavior may show up again in different organisms.
ReplyDeleteHomosexual behavior is 2 organisms of the same species of the same gender displaying sexual behaviors. I agree with Andrew that a mutation in the organism's genes can cause homosexual behavior. According to the theory of evolution the purpose of an organism is to reproduce and enhance the survival or your species. Homosexuality behavior may not produce offspring but it can enhance the survival of the species. If there are too many new organisms being born, there wouldn't be enough resources for all of them to live on. Homosexual behavior can benefit the species by helping family members ensure that their offspring live long enough to produce offspring (http://www.newscientist.com/article/dn13674-evolution-myths-natural-selection-cannot-explain-homosexuality.html). For example the male red-winged black bird that doesn't mate with any female invades established territories (Coyne 150). Even though the male isn't producing offspring, the male is still helping the survival of its species.
ReplyDeleteI also agree with Jolyn that homosexual behavior can be caused because of the need to have a companion. Sometimes the right opposite sex isn't around due to behavior differences and body differences, organisms have to fine a new way to please themselves sexually (Coyne 229). As long as the homosexual behavior isn't harming the survival of the organism's species, homosexual behavior isn't destroying evolution.