re: How do you explain the origin of the various human races scientifically?

Educate me, smartass!

Man, go pick up a book, and stop making dumb threads.

I'm not skipping through 9 pages of thread but I have to ask, has "A Troublesome Inheritance" by Nicholas Wade been mentioned yet? I just finished it and I know there's been some pretty intense backlash from the scientific community but it offers some interesting insights on how we've continued to evolve and how we may one day become entirely separate species. It's a taboo subject in many circles but it really shouldn't be.

You are deflecting because you are clueless...

I started a thread that requests for folks to explain some basic principles and I ask a question and you cannot put together a coherent thought that will sufficiently address the question. Why? Because it is easier to say read a book than to actually account for the underlying principles that address the subject matter.

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How do you explain the origin of the various human races scientifically?
Educate me, smartass!

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there is no end goal in evolution, the different races of humans evolved from mutations over dozens of generations within an isolated population that (and here is what 'survival of the fittest' actually means) allowed members withing those populations to 'fit' better in their niche in response to selective (read environmental) pressures and pass on those acquired mutations at higher rates.

humans are intelligent animals able to extract every resource from a niche therefore we havent reached a point in our evolution that would force an evolutionary advantage to one race, because we grow food, we build shelters and clothing, we use medicine....

we dont have forcing naturally selective pressures on our populations any longer, in other words we 'fit' at this moment in time nicely. So what you are looking for and would think of as some singled out advantageous mutation is diluted within the genome

You've been addressed on all of your points except for the last question you asked, which is about as stupid a question as I can fathom.

Humans descend from a common ancestor. As they spread across the globe they became isolated over the course of 100,000 years and "diversified", as you like to call it.

That's about as simple as I can put it. This is based on fossil and genetic evidence.

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These groups while human are so different. If we had been evolving for so long wouldn't there be a dominant race by now or at least much more uniformity? It just seems strange that there are so many different races of one species and they are so different in appearance. How do we explain this scientifically? (The same could said for dogs and other species but I wanted to hear the answer for humans.)

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First, stop using the word "race". You should be employing a different a word - specifically, "population". A population is a select group of interbreeding individuals who tend to breed more with themselves than with others. Race, on the other hand, is a sociocultural construct. As such, the word experiences alterations in its meaning over time depending on the target group.

A "race" isn't a biological entity. Among humans, race has no taxonomic significance. Humans belong to the same hominid subspecies - Homo sapiens sapiens. Subjective conceptions of "race", as mentioned, vary over time based on subjectively perceived traits.

Additionally, most dog breeds are fairly new, and are the direct result of artificial selection. Never underestimate the potency of selective breeding, and its ability to rapidly alter physical characteristics within relatively short time periods. Most dog breeds are NOT genetically distinct, aside from perhaps a few loci.

Similarly, human diversity is actually exceptionally low. The human migration out of Africa started around 100,000 years ago, and numerous bottlenecks have reduced our population size over the years. There are currently about 8 billion people inhabiting Earth. However, if you assess our collective genetic diversity as a proxy for the "effective" human population size, it would only be about 5,000 - 10,000.

The differences can be attributed to a lack of gene flow between populations. When barriers exist, gene flow is encumbered or halted, and unique characteristics arise within a given population. If severe enough, this can lead to speciation. Think of human populations as collections of genetic markers. Some populations have certain markers, other populations have other markers. Many populations of humans have special genetic markers that confer advantages to their specific environment. The most obvious example of this is sickle-cell anemia, and its increased prevalence in populations where malaria is present.

The difference between two human populations really comes down to only just a few discrepancies at specific genetic loci. There isn't nearly as much diversity among various human populations as your question suggests.

I'm not defending 8Up's statement, but what would you expect to find from an ancient garden - a garden that had nothing but vegetation? How would you expect to positively identify the recovered remains of a person several thousand years old? Also, the political climate of the region has made archaeological expeditions almost impossible.

Again, I am not arguing the points of 8Up, I am merely stating the flaws in your statements.

LoveThatMoney

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There are only 3 different "races": Mongoloid, Caucasoid, and Negroid.

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A Mongoloid is not a Mongolian.

Thank you! It took a while but finally someone who can make some sense here!