About races and evolution?

Question

This question has no racist insinuation or anything, I am simply wondering how the different races were created: does one human race derive from another? Does each race derive from a different race of ape? Do the different races derive from random mutations that created them, from a specific but common ancestor? Also what is the case in cats and dogs for example, who have so many different races?

Answer 1

> does one human race derive from another
Yes. Anatomically modern humans have been around for about 125,000 years. People who think like us have been around for about 50,000 years. There's been considerable gene flow all across this time span.

> Does each race derive from a different race of ape
Nope. All human races derive from Homo sapiens sapiens.
All humans, before the races were isolated.

> Do the different races derive from random mutations that created them, from a specific but common ancestor
Partly. Random mutation made the variants -- but selection and isolation / genetic drift kept them and made them more common in a particular population.

> Also what is the case in cats and dogs for example, who have so many different races?
Same as with humans, but the isolation is purely reproductive, and the selection is done by people.

Answer 2

There is only one species of humans, which suggests that we evolved from a common ancestor and our variations developed as we expanded geographically and populations became established in different environments. While random mutation causes many variations that are not of great significance to survival, some had strong survival value, such as lots of melanin that protects the skin from sun exposure in hot sunny climates, and reduced melanin in climates with long winters that allows vitamin D to be synthesized in adequate quantities.

In wild dogs and cats, the same process happens. Isolation of populations has resulted in divergence of species into multiple species though, which hasn't happened with humans. Housecats and tigers have a common ancestor, as do wolves and poodles. Deliberate selective breeding of domesticated animals has created various breeds; dogs may be bred to enhance characteristics that make them better for hunting, or sled-pulling, or sheep-herding (or flea-baiting). The differences aren't enough to make them different species -- they can still interbreed if other physical characteristics don't prevent it.

Cattle and sheep (and chicken and goat etc.) breeds have been developed by breeders over time in order to produce better milk or meat. To a lesser extent, housecats have been bred to create differences in size or in fur color & texture, although I doubt anyone's ever tried to breed a cat that'd pull a plow or round up sheep. Variations among housecats seem to have little survival significance one way or the other (although a shelter worker told me that black kittens are less likely to get adopted than more colorful ones; this could tend to reduce their numbers over time).

Short answer: mutation + isolation engenders diversity.

Answer 3

Evolutionary change requires two things: genetic mutation, and natural selection. Races did not develop from evolutionary change, they have developed from natural selection and genetic drift. This is the same for all species that have races. With cats and dogs, the different varieties have been intentionally bred to create differences through selective breeding.

http://en.wikipedia.org/wiki/Natural_selection
http://en.wikipedia.org/wiki/Genetic_drift

Races in humans are almost indistinguishable genetically, so it is very unlikely that human races, or races in any species come from different ancestors. The genetic variation within different populations of 'white' people is larger than than the genetic differences between races. There is not one single gene that distinguishes races by occurring exclusively within one race.

All species have genetic variation. When a species has many populations that occupy different environments, each population experiences different selective pressures. For example, the traits needed for people to survive in Scandinavia are a lot different than the traits needed to survive in a tropical rainforest. In a tropical rainforest, people need to contend with bugs, infections, constant moisture, and heat; while people in Scandinavia need to contend with cold, snow, and long winters with low food resources. So, natural selection would favor different genetic characteristics in each population - this is caused by natural selection against unfavorable traits and random genetic drift. Neither of these changes occur from mutation - its just a statistical change in the number of people who have a given trait.

Answer 4

According to my biodiversity class there are many ways to classify species, but the most common and accurate one explains how every species evolved from one common ancestor. I think everything comes from the common ancestor and evolution is caused by several factors which include mutations. Looking at the Hardy-Weinberg Principle might help you understand a little more...

Answer 5

races were invented by some dumb people, described in a semi-scientifical why by dumb anthropologists and geneticians and are perpetuated today by dumb governments (like the US).

Races don't exist. At least not in biological terms. Biology is much to complex to be understand in term of races.