If there is only One species of humans, Why is there only one?

Question

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Answer 1

Well the simple answer to your question is that another species of human would not technically be a human. The term human relates only to the species of humans that exist at the present. It is possible that humans might further evolve into new species in the future but at the present humans are extremely biologically fit in their present state and any further evolution if it is even possible would take thousands of years.

Answer 2

For speciation to occur, populations have to be isolated, usually for very long periods of time.

For instance, let's say that humans never discovered the ability to travel by boat or plane. The Australian aborigines, for instance, would have been cut off from other human populations and their gene pool would have been isolated. Over many, many generations, they may have become so different that they'd no longer be able to interbreed with any other populations, even if those populations had come into contact with them. They would, in effect, be a new species of the genus Homo.

I use the aborigines as an example just because they were isolated on an island. Islands are great places for new species to develop.

As it turns out, modern methods of travel allow humans to cover every inch of the globe. Therefore, the necessary isolation to produce a new species is not there. Never will be, unless we colonize space and some colony gets isolated somehow.

Answer 3

In the past there have definitely been other human species. In some areas, peoples such as Homo erectus and Homo sapiens may have co-existed for certain periods of time. If Homo floriensis (the Flores hobbit mentioned earlier) turns out to be a valid new species, these may also have existed at the same time as Homo sapiens.

Neandertal is generally considered to be a subspecies of Homo sapiens, and so may or may not count as a different group for your purposes.

As to why there's only one now, it's mostly just a matter of luck and timing. It just so happens that at the current time there is only one existing species of man. It wasn't always true, and there could definitely be speciation events in the future that will bring about new and different species of man again.

There doesn't appear to be any specific reason why writing, technology and civilization happened to develop at a time when only Homo sapiens was around. It would be interesting to speculate as to what our cultures and civilizations, let alone our religions, would look like if there was in fact a separate, sentient race on the planet.

Answer 4

The term human seems to imply one species. Is a Neanderthal human - I don't know. If your definition of human is broad enough then, I guess there are more species. If your definition of human is very specific (species), then of course it is one species (sorry for the redundancy). I am way out of the mainstream but I might broaden the definition to include possible creatures such as Bigfoot, Almasti, Yeti and Orang Pendek any one of which might survive to present and each would be a different species.

Answer 5

Have you heard of the Flores Hobbit? It's another species of Human that may have been living side by side with Indonesian natives until only a few hundred years ago. If discoveries like this are still being made, who knows!!! There may even still be a small population of them on the less accessible parts of the island.

Answer 6

If the "human" spectrum was widened, all primates would be a part of it. It's selectively narrow of our unique consciousness.

Several species of Homo Sapien predacessors existed before us, until eventually the similar species formed a common genetic pool, as is illustrated by the last thousand years of human creed and warfare.

Well-documented modern examples of how earlier species may have mixed are illustrated by such events as the Spanish invasion of the Aztecs, or the Aboriginal holocaust depicted in Australian cave paintings. They aren't physical proof of interspecies mating, but they indicate its likelihood.

Answer 7

Actually, there were several species of "humans" running around different parts of the world. Over the thousands of years, we met, evolved, and have become one "likeness".

Answer 8

Who said there is only one? There are several groups of homo sapiens running around with profound differences between them in terms of body structure and aclimation to the the environment in which they live.

Just one trait which might fascinate you is teeth.

The next time you are talking to someone check out his or her eye-teeth. Some people have flat eye teeth. Some people have sharp eye-teeth, like small fangs.

By that, I know that their ancestors have been agrarian (for the flats) or more hunter gatherer(with the fangs).

Other traits are present as well, bone density, ribcage size, muscle strength to muscle size, etc.

Answer 9

According to the fossil record, Out of all the different beginnings of homonym's.Our species is the only one that made it this far.Survival of the fittest or and luck.

Answer 10

It's a "self-defining" thing; if there was a different species, by definition they wouldn't be human.