Sympatric speciation in modern humans (User:Super Quantum immortal)
(fix the formating latter)
They are 2 major speciation roots. The first 1 that every one knows, is physical isolation. The second 1, sympatric speciation, is more subtle, speciation occurs with out physical segregation. They are many possibilities, but a nice example is with birds beaks. The beak mutates, in order to adapt in the consumption of a new food source, simultaneously, the mutation causes the bird to sign differently, not attracting non mutated birds and interbreeding with in its own group.
In humans, because of technological developments, only sympatric speciation is possible in the relatively near future. Its a bit hard to isolate a human population when we can go anywhere in the world in less then 2 days.
Potential speciating individuals should be able to come in to contact with each other, in order to perform strong enough assortive mating so that "hybridization" is kept low enough. As with the bird, potential sympatric speciation should start with what appears as some form of sexual aberration. The most obvious candidates to look for, is in the LGBTQI(strong evidence for genetic causes) communities. They already form communities where assortive mating can happen. From those TBQI don't provide a potential barrier to reproduction with other populations.
On the other hand, LG provide powerful potential mating barriers. They can't breed with each other, but this could be over come in the near future by technological means. The hard way would be to directly form an embryo with 2 same sex gametes. A much faster and easier way, would be to have some sort of second gender for LG.
The best potential candidates for the job, are LG fertile transsexuals, lets call them male lesbians and female Gays, since we discuss speciation in to a lesbian human species and a gay human species (i refer to there reproductive potential, not there heads). Being biologically of the right gender, all its needed, is to preserve there fertility. From the 2, the LM are the easiest to preserve fertility, they can at a minimum, just freeze loads of sperm before there transition (one healthy ejaculation could in theory impregnate all the women of Europe and more ), anecdotal evidence(i read it in a forum, i don't think there's any research on the issue) suggest that fertility in MTF comes back when HRT stops. An important note, on MTF transsexuals, is that irreversible squeletical changes occur at puberty, if HRT start before puberty, they would be totally indistinguishable from standard women(Kim Petras 12), except with there genitals. Fertility might then get more complex then with transsexuals that transitioned as adults, but its not impossible. The female L, is normally fertile female.
For the GF, that is a bit more complex, biological females don't produce much gametes (can't really bank it up), and they are supposed to do the heavy lifting by being pregnant. Preserving fertility can be harder, yet it was done, some FTM became pregnant after ceasing there hormone regime. Lactation is also an issue, bolted milk is a sub optimum solution.
Actually it seams the greatest difficulty is social discrimination, a FTM becoming pregnant, is difficult not to notice and provoke an out cry. A lesbian becoming pregnant is not a big deal, even if the father is a MTF.
LG speciation theory, illustrates nicely the messy and random way natural selection works, requiring a good enough deal of imperfection to be able to work with. We have one mutation on one hand (LG) that is rather detrimental to reproduction, we have an other (TL/TG) that is too detrimental to reproduction. The 2 meet, and the situation normalizes.
This process will probably be done only once. After speciation has occured, the new LG will simply integrate in existing LG communities. Being far less fertile combinations, they would allow some hybridization, gene flow will be reduced.
Autism!= retardation or handicapped. Autism is about social interaction problems with neurotypicals. Problems that disappear when they are put with each other.
An other potential speciating group, under important pressure. Strong social divide between autistics and NTs. Strong social taboo on autism. Contrary to the LGBQTI group, social acceptance will not bridge the social divide. Evidence of assortive mating. Autistic community is under formation, in the process of becoming politically active and advocating for it self.
Special needs schools for autistics(!= retarded) will contribute to the assortive matting. Beater screening will have the unintended effect of increasing the divide.
More long term, maybe the internet will help in a generalized rise of assortive mating, making other groups susceptible in speciating.
Contrary to what you might think. Speciation is not a disaster. Natural election actively tries to make new species. The idea is that you get more diversity, so if something really bad happens, at least some will survive by shear luck.
As a single species, a single diseases could kill millions. As multiple species, we would have at lest some immunity from the others diseases. As multiple species, we will be able to specialise in different aspects of the functioning of an advance civilization. There's going to be symbiotic interdependence.