Humans - the lone species?

Question

Why do you think that humans are the only species of our kind? Do you know of any other animals that only have one species?

Answer 1

almost all animals have one species.  the question you want to be answered is.

Are we the only ones with no coevolution within our species?

and i would have to say.  only god knows.

Answer 2

Because Allah has seperated us from the rest of creation, and has not made us like them...

so while you might see many important variations in other animal species (such as an elephant having trunks or not) you wont see those in humans

Answer 3

I'd say that it's practically human nature to eliminate our possible competition.  Our ancestors may have "taken out" any similar species, even though there has not been any evidence (that I've heard of).  Of course, it is possible that every similar species simply died out on its own course.

Answer 4

A large part of modern humans homogeneity has to do with humans ability to share genes widely.  A new species would only be able to arise when an interbreeding species has be geographically separated.  You would have to stop all the gene flow between the two separated groups and then either a large amount of mutations or genetic drift would need to occur to create a new species.  This is highly unlikely in humans because we have a propensity to be long distance travels and human history shows a lot of interbreeding between different human groups.  Basically there hasn't been the appropriate circumstances in our history.  The most plausible circumstances maybe something like interstellar colonies in the distant future (although probably not likely because there would still be transmission of genes between colonies).  Dr. Henry Harpending has recently published a paper about humans actually being more genetically different now then they have been in the last 10 to 20,000 years.

Answer 5

I have to go with the response given by Eternal. There have been additional species in the past. Here's another part to this mystery however. Humans haven't been around all that long, comparatively speaking. There have been some variations of humans in the past. But if we were like other animals, and groups were separated geographically for tens of thousands of generations, then other sub species would probably evolve based on differences in diet and environment. I really don't know. It's just a guess.

Answer 6

25,000 years ago, there were at least four types of Hominins, with which we could perhaps successfully breed with some of them!

Since then, we've probably out-competed them, which led to their extinction!

1) Homo sapiens (modern humans)

2) Homo floresiensis (13,000 ya)

3) Homo neanderthalensis (24,000 ya)

4) Homo erectus-Java (25,000 ya)