There are many different species of mostly the same animal… That differ only in the slightest details…
But humans despite evolving separately for a very long time are still the same species regardless of the race.
In: Biology
A simple definition is the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring. But it’s really useless in some cases, for example Polar and Grizzly bears can and do produce fertile offspring but they are very different in habit and appearance and it’s far more sensible to name them as separate species.
Generally speaking a population with significant enough genetic, physical or habitual differences that normally breeds independently is regarded as a separate species even if they have no trouble interbreeding with another species.
Humans are very genetically similar and almost no populations have really had enough time to evolve seperately. The whole of Afro-Eurasia is connected and there has always been at least some flow of genes so even relatively isolated peoples like the Khoisan have some cosmopolitan genes.
Australia was probably always connected to the mainland a little bit by the Torres Straight Islanders. The first Americans arrived about 13,500 years ago and were cut off by the seas rising at the end of the ice age, but there was another large prehistoric influx of Inuits from Siberia about 5,000 years ago and some evidence of contact thereafter so for both native Australians and Americans the separation wasn’t perfect and since humans are slow growing animals 13,000 years or even 50,000 years aren’t so long as they might be: Evolution is measured in generations rather than time which is about 26.9 years for a human, whereas it would be 12 weeks or so for a house mouse.
Latest Answers