What is the biological cause of different races having different physical characteristics?
Agreed, @Sandy. I think the Sun's exposure is one of the many factors. Environmental and eating habits are too, I believe.
- SandyLv 78 months agoFavourite answer
exposure to the sun. Africa is on the equator, so the people are darker. and the further away, the lighter the skin color.
- Anonymous8 months ago
Pure biological cause in races (not environments or foods or clothes):
- Female monkey fu/c... by male advanced 'alien' specie (will be 100% different human from:)
- Female advanced 'alien' specie fu/c.. by male monkey.
Humans evolved? It is mistake, it's been crossing. Aliens should save their race.
The rest is involved in biological cause:
- environment (houses, pyramids, caves, fields, other forms - secret)
- foods (by sources, types, forms, filtered, combinations)
- supplements ()
- drugs ()
- medicament s ()
- ... activities ... ()
Results are: different
continuation ... physical characteristics, physical capabilities, physical activities, physical properties... etc.
... brain impulses, different evolving or devolving genetics, different activities, different temperatures, different blood groups (or not important blood at all).
= different races.
- CowboyLv 68 months ago
Mostly, it's all in the eye. Your eye, not theirs.
- Gray BoldLv 78 months ago
Genetic change occurs in a population when natural selection and mutations act on its genetic variability. Genetic changes may result in visible structures, or may adjust physiological activity in a way that suits the habitat. Habitats and biota do frequently change. Therefore, it follows that the process of adaptation is never finally complete. Over time, it may happen that the environment changes little, and the population comes to fit its surroundings better and better.
- What do you think of the answers? You can sign in to give your opinion on the answer.
- Anonymous8 months ago
They are adapatations to local environments.
For example, curly hair allows air to flow through it to cool the scalp. Straight hair that lies flat insulates the scalp from cold air. That is why African Americans wear hats and hoodies, but many East Asians carry umbrellas when they are outside, to shield their head from the hot sun. More facial and body hair insulates the skin against heat loss. Africans and SE Asians have little body hair and facial hair because they do not need the insulation.
The tall and narrow nose bridge allows the respiratory turbinates inside the nose to recapture more of the warmth from the air coming out of the lungs and returns it to the lung. Thin lips, short arms and legs, rounded torso reduces heat loss to the environment by reducing the amount of surface area that is exposed to the environment. Cold adapted folks like Europeans and north Asians have more fat under the skin, which also make their bra sizes bigger. Russian and Scandinavian women average a D cup bra size. Most Europeans, Australians, and Americans average a C cup, but Africans and SE Asians average a B cup in bra size.
The slightly larger brain of Europeans and N Asians evolved because of the need to figure out where their next meals will come from while they lived in a cold and barren landscape during the last ice age.
The light skin allows more sunlight to be absorbed to make vitamin D. Vitamin D helps the body absorb calcium from food, and prevents rickets, which can cause broken and deformed bones, and a difficult pregnancy since the developing young relies on the mother for calcium. Light skin evolved in people living in cold climates because the winter days are short and because they have to wear clothes to stay warm, blocking the skin from being exposed to sunlight. People who live in the tropics do not need to wear clothes, and so they need dark skin to block out the harmful, cancer causing UV light. Blue eyes is a byproduct of evolution, although it may be helpful in absorbing more UV light to make vitamin D. The cubs of big cats have blue eyes when young, and a light colored nose pad, helping them absorb sunlight to make vitamin D. As they grow older, their nose pads and eyes turn dark with pigments to avoid eye cancer and skin cancer. Blue-eyed folks have a higher incidence of eye cancer.
- ZirpLv 78 months ago
different genetics being passed down to posterity
Humans don't really come in races. Genetically we are so similar that scientists assume we nearly went extinct, at least twice
- οικοςLv 78 months ago
Selection for different environmental conditions, followed by sexual selection. For example, a long-nosed Scandinavian would not thrive well in the Gobi Desert.
- JazSincLv 78 months ago
o Mutations make new alleles and even new genes
o Selection. Advantageous alleles in the local environment tend to increase in frequency and disadvantageous alleles tend to decrease in frequency.
o Reproductive (semi)isolation of populations. You're more likely to marry the girl next door than to marry the girl who lives on the other side of the planet. After 20,000 to 60,000 years of the above, your neighborhood may not look quite like the neighborhood of the people who live on the other side of the planet.
o Genetic drift. Hey, uncommon alleles in small populations can be lost by accidents and local disasters. "Founder effect" and "bottleneck" are subtopics of genetic drift.
o Gene flow. People immigrating to another population can bring new alleles with them. People emigrating from a small population can take their uncommon alleles with them. As someone else mentioned, some populations of our species hybridized to some extent with other hominin species such as Neanderthals and Denisovans.
- yLv 78 months ago
Homo neanderthal and Homo denisovan dna, for starters
- nineteenthlyLv 78 months ago
Race is a social construct.
- GregLv 78 months ago
Different environmental conditions gave a survival advantage to certain genetic characteristics. Farmers have developed better crops for over 1000 years by using seeds/cuttings from plants that did better. This resulted in changes such as corn growing taller.