by Gibbous Moon on Mon May 19, 2008 2:57 pm
In order for natural selection to work two things have to happen.
Firstly, there has to a replicator. Something that is capable of being replicated usually but always perfectly. If replication were perfect there would be no variation for nature to select against. This the genotype.
Secondly, the variations produced must have an impact on the ability of the replicator to be replicated. They must increase (or decrease) the replicators chance of being copied. This is the phenotype.
Genes are the replicators. The get themselves copied (with occasional mutations) and through their effect on the development of the embryo they produce a body that interacts with the environment successfully or not. Success determined by whether that underpin become more common or not and not success as determined by whether the individual actually has offspring themselves or not.
Survival of the fittest by natural selection means that those most fitted (best adapted) to the environment survive. Survival of the fittest works at the level of genes (not individuals – who are merely carriers of genes, or species – which are merely groups of individuals with similar genes).
Therefore the fact that homosexuality in humans exists means either one of two things. Either there is a gene (or a group of genes) for homosexuality and that those genes continue to be passed on and are therefore fit (adapted) to their environment or there is no gene for homosexuality and it’s learned or random behaviour.
Conversely, those replicators that are persistent must have a degree of fitness. By definition, if they have consistently made it into the next generation they must have some adaptive advantage.
My personal view is that genes that work well with genes that code for homosexuality gain a Dutch Uncle benefit. Of ten offspring with similar genes (say for blue eyes) one will tend not to have offspring themselves and will pour resources into supporting blue eyed nieces and thus crowd out resources from their brown eyed rivals.
Or you could argue that you get a better expression of the phenotype for some useful specialisms when you combine the genotype for that specialism with the genotype for homosexuality. It’s a special case of the Dutch Uncle and I don’t buy it myself.
GM
Last edited by
Gibbous Moon on Mon May 19, 2008 4:00 pm, edited 1 time in total.