The species definition is that a species is composed of animals that will breed in the wild and produce fertile offspring. All groups of humans known fit that definition. My guess is that your taruntulas either don't interbreed in the wild, or the spider taxonomists made a mistake.
So if two beings from territory where they would never ordinarily come into contract with another procreate, say through artificially making it so they share the same environs, then their offspring are what... a non species?
Lions and tigers do coexist in parts of Asia. They do not interbreed in the wild. Where groups of different looking humans coexist, they do interbreed, and very readily. - - - Updated - - - Just shows you haven't been around many black people. I used to say the same until I worked in a 95% black high school in Georgia. Now, I can recognize differences in blacks much more than I could before that.
Probably behavioral differences or differences in their mating season. Regardless, that is some of the evidence for them being separate species. Humans are definitely not separate species under that criteria.
Lions have a definite social structure and live in prides. Tigers are solitary. Lionesses rarely are alone. Lions keep pretty good control over their lionesses, and especially when they are in heat, would never let a male tiger close. I can't easily think of why a prideless lion wouldn't mate with a tigress, except that maybe his mating style wouldn't work. The other thing is that from what I've read, very few ligers or tigons are fertile, and most pregnancies between lions and tigers result in miscarriage. Different groups of humans rarely have those problems.
Could it perhaps be better said that the reason they would not do so, notwithstanding the fact that those things ^^ may be true, that they are naturally wired not to, since doing so would eventually destroy the unique genetic line of both?
Another example is different breeds of dogs, or different types of roses. They may all be within the same species group but no one questions that there are different types with completely different genetic traits. It is also possible to breed cherry blossom trees with sweet cherries to produce fertile offspring. Both of these types of cherries have 16 chromosomes, and it is not entirely clear to taxonomists whether they should be categorized in the same species. Sweet cherries can also be crossbred with sour cherries, but in that case the result is a hybrid that produces sterile seeds. Like crossbreeding a horse and donkey to produce a mule, the mule cannot further reproduce. In the case of the Savannah cat, which is a hybrid between an African serval and a domestic cat, the males are sterile while the females can reproduce (though they have an increased chance of spontaneous abortion). This is regarded as an example of hybrid inviability, where a cross between two species results in a decreased level of genetic fitness. Outbreeding Depression in Human populations?
But, to put it bluntly, a great number of humans will (*)(*)(*)(*) any human of the opposite sex. There is but a single human species.
Not vast, or we couldn't interbreed so readily. Human beings aren't even in separate subspecies according to most biologists. Please take your white supremacist nonsense back to Stormfront or some other white hate site. Social differences, yes, biological differences, not much.
Ever heard of the concept of a subspecies ? There are countless examples in nature. In Alaska there are two separate populations of caribou, one occupies a more northerly range and the other occupies a range just a little further south. The two ranges overlap, but the two separate populations rarely ever interbreed with each other, despite being the same species. One group has evolved to be better suited to the more northern environment, and interbreeding would take away their competitive advantage in that area. You might want to read about how allopatric speciation works. Biologists have also observed numerous instances of partial reproductive isolation in nature, where they can see a single species beginning to break into two separate subspecies, and ultimately someday perhaps different species. This comes about because of a concept called speciation, where there are two separate ecological niches that are easier for two different organisms to occupy than a single organism. Usually these separate ecological niches are a different geographic area, but sometimes it can be the same area. In the case of warbler birds, there are five different types of warblers that tend to occupy different parts of the same tree. Each warbler has evolved separately to become best suited to occupy a certain part of the tree.
It has long been a rather "common" notion that the different races were "subspecies", especially amongst the bigots, the elitists and stupid. Supremacists and nationalists are also known to espouse such drivel and even spread it around. Fortunately, modern science has pretty well demonstrated that humans are a single species.
On average, the brains of African-Americans are 5% smaller than the brains of Whites and 6% smaller than East Asians, according to studies of brain weight at autopsy, endocranial volume of empty skulls, head size measurements by the U.S. military and NASA, and two dozen MRI volumetric studies. Does this explain why blacks do worst in school than whites and Asians? Considering that even malnourished Asians from poor countries have a larger brain on average than well fed blacks from western countries, does this not point to a genetic component in the differences of intelligence between different ethnic groups? These are my sources: Beals, K. L., Smith, C. L., & Dodd, S. M. (1984). Brain size, cranial morphology, climate, and time machines. Current Anthropology 25, 301–330. Ho, K. C., Roessmann, U., Straumfjord, J. V., & Monroe, G. (1980). Analysis of brain weight: I and II. Archives of Pathology and Laboratory Medicine 104, 635–645. Johnson F. W. & Jensen (1994). Race and sex differences in head size and IQ. Intelligence 18: 309–33 Rushton JP. (1997). Cranial size and IQ in Asian Americans from birth to age seven. Intelligence 25: 7–20. Rushton JP (1991). Mongoloid-Caucasoid differences in brain size from military samples [and NASA]. Intelligence 15: 351–9.
Yes, but they don't breed "true" that is, they don't produce the same species as the parents and they usually can't reproduce more than one generation That being said there is immense variation possible within a species. All dogs are one species, as they all can (theoretically) breed with each other. That's how such great variation as dogs display came about. This, btw, is one of Darwin's great insights. WHY are all conservatives so obsessed that we all be the same? What do they want, a race of clones?
Fine with me. I'd prefer it if you go to your racist kind and discuss. You obviously have little background in science.
