How is it proven that races are adapative and not progressive?

Question

In other words, I think my teachers were Christian. So I am trying to inform myself on my own. Thanks.

Answer 1

Racism is taught or learned by environment, social structure or implied that one is superior to another by reason of race.  Some are given special privileges/advantages over others.

A few years back Oprah Winfrey did a social experiment in her studio.  People were divided by eye color.  Those with brown eyes were given gifts and special treatment, while others with blue or green eyes were left out and left standing.  Some were of family groups that came to see the show together.  Before long they were openly hostile towards each other because they were treated differently.  It is a project worth repeating for observation and research.  

I would say that racism  and sexism in and of themselves are social constructs, not inherent.  If you place toddlers and babies together, they acknowledge, play and smile with each other willingly and get along very well, until adults intercede.

Answer 2

Well, first of all, human "races" don't really exist the way biologists define the term.  We don't fall into natural genetic divisions.  Race is a social concept.  Think about the different "rules" different cultures have for "mixed" children.

There ARE population differences, and those differences are generally adaptive to the local environment.  For example, if you live in a cold climate, you want to be short and round to hold in heat.  If you live in a hot climate, you want to be tall and thin to disperse heat.  

If you live in a cold climate, it's an advantage to have a long, thin nose, so that the air has a chance to warm itself before it hits your lungs.  If you don't, a wider nose that allows as much air as possible is better.

If you live in a sunny climate, you want a lot of melanin in your skin to protect from skin cancer.  If you live in a less-sunny climate, you want lighter skin so that you can get Vitamin D from the small amount of available sunlight.  Thus, we see a wide spectrum of skin shades, from very dark near the equator to very pale in the far north.

But the truth is that all of these "differences" are very superficial, and the genetic difference between "races" is pretty much nonexixtent.  90% of the genetic variation in humans is within-group variation; only about 10% of the genetic variation is between-group variation.

There is no biological difference in intelligence, ability, or personality from one culture to another.  Racism is therefore not just morally wrong, but scientifically incorrect.

Answer 3

The distiction between progressive and adaptive is easy, humans have the ability to adapt to any environment and survive, eskimoes survived in an artic environment while arabic cultures excelled in extremly hot climates.  Progressive I would think entail making progress, culturally or technologically, while adapting.The discussion over racism is a moot issue because the "experiment" that is credited to Oprah wa an experiment that was originally conducted the day after Martin Luther King, Jr. was killed, a teacher, Jane Elliot, in a small town in Iowa tried a daring classroom experiment. She decided to treat children with blue eyes as superior to children with brown eyes. "A Class Divided" is a video that shows what those children learned about discrimination and how it still affects them today, showing a reunion of that third grade class.

Humans will separate themselves on the least noticable differences.

What are the differences between races and how long ago did these differences evolve?

Answering questions on race is challenging given that most anthropologists regard race as a cultural concept rather than a biological reality. In the biological sciences, the term race has historically been used to describe a distinct population in which all the members share a suite of biological traits. Today, most anthropologists agree that there is no way to divide the world's human population in the cut-and-dry manner that the definition of race traditionally requires.

Over the past two hundred years or more, scholars have attempted to define different races. Ever since their first encounters with native (indigenous) populations, westerners have studies variation within the human species. Toward the end of the eighteenth century, the first cohesive scientific theories were produced that classified and named different races. The problem with many of these classifications is that they used observed characteristics and personalities to place different populations or races on a single line or ladder. This ladder implied that the highest rung, incidentally the European race, was ideal and the other races occupying lower rungs were less evolved or degenerate from the ideal.

Attempts to create categories of biological races have centered on phenotypic differences. A phenotype is the entirety of traits that an individual possesses, including external characteristics such as eye color and shape, body size and shape, hair color and texture, and skin color. In recent years attempts have also been made to evaluate genotypic differences to justify biological races. Genotype refers to a person's genetic makeup. These attempts have tried to define clusters of characteristics in one population that are not found in other populations. These clusters supposedly would enable different populations to be divided into distinct races. Such attempts have failed, however, and what researchers have found is that biological variations exist on a cline rather than in delimited geographic clusters with gaps in between. A cline refers to a gradual change of a trait and its frequency from one place to another within a species or population. The change usually corresponds to some change in the environment across the geographic range of a species. Any boundary line drawn at a point along the continuum is therefore arbitrary. So, the idea of distinct races defined by hard-and-fast differences has fallen apart as anthropologists have studied the genetic and physical characteristics of human populations.

Although anthropologists thus no longer classify populations in terms of races, they do recognize that human populations exhibit diverse phenotypes. Different traits are, for example, very useful in the field of forensic anthropology. A forensic anthropologist must extract as much information as possible to assist in the identification of an individual. Part of that job requires identifying that individual's ancestral phenotype. Ancestral phenotypes are suites of traits that are associated with geographic populations. At first, this sounds a lot like a synonym for race; however, the difference lies in the lack of distinct divisions. The task simply relies on the idea that any given individual may have characteristics known to be common in a particular geographic area. Determining ancestry comes from familiarity with the clinal distribution of phenotypic characteristics.

So, when in the past did phenotypic diversity of the sort found in modern humans evolve? To answer this question, anthropologists usually look to correlations that exist between external traits and environmental variations. The evolution of varied skin color offers a good example. At some point in human evolution the amount and length of body hair commonly seen as a thick coat in other primates was greatly reduced. Only a fine coat of body hair was retained, which means that the skin of modern people is much more exposed to the elements than in other primates.

Increases and decreases in skin pigmentation became a crucial way of adapting to the diverse climate zones that humans, especially modern humans, came to inhabit.The results of a recent study demonstrate that skin coloration is strongly correlated with ultraviolet (UV) radiation levels and latitude. The color of a person's skin is the result of the amount of melanin pigment in the skin. More melanin means darker skin. Melanin absorbs UV radiation from the sun. UV radiation aids the body in vitamin D synthesis; however, it also causes nutrient photolysis (chemical decomposition caused by radiant energy) particularly the photolysis of folate, a converted form of folic acid that is crucial to reproductive success.

Due to small amounts of melanin beneath their thick hair, other primates tend to have light colored skin over most of their body. Exposed areas such as the face and hands, though, have varying degrees of melanin. So, for example, common chimpanzees often have light facial skin, while other apes also closely related to humans have darkly-pigmented faces, even though the skin beneath their thick coats is often light in color. Using other primates as a guide, then, our ancestors could have had light colored skin over parts of their bodies prior to the time when hairiness was greatly reduced. However, it is impossible to prove ancestral skin pigmentation.

Lacking any preserved paleo-skin to go on, paleoanthropologists have looked to skeletal evidence for some clues. With the evolution of the species Homo ergaster (or early African Homo erectus), there was an important shift in body proportions. Appearing about 1.7 million years ago, Homo ergaster was the first tall human species we know of. Its body was strong and powerful, which suggests that this species was susceptible to heat stress as it moved around during the day. The best-known specimen of this species, the "Turkana Boy" ( KNM WT15000 ) from northern Kenya, had a narrow pelvis and a skeleton reminiscent of the long, linear bodies evident in modern peoples from hot equatorial environments. Looking at the nasal bones of the face, Homo ergaster may also have been the oldest human to evolve an enlarged nasal cavity effective in moisturizing inhaled air and precipitating the moisture on to the nasal membranes during exhalation. This matter of moistening dry air but not exhaling the moisture is a critical factor in preventing water loss in dry environments during the process of breathing.

This combination of evidence points to the possibility that Homo ergaster was the first hominin to be strongly affected by a hot, dry environment. It's in this type of habitat that sweat glands similar to our own and skin exposure due to hair reduction are likely to have evolved. These developments enabled the evaporative cooling of sweaty skin - a novel and effective way of regulating body temperature in a hot setting. Since Homo ergaster originated in Africa, UV radiation levels would have been high, perhaps similar to their levels in historic times. Low melanin levels would have allowed a great deal of UV radiation to penetrate the skin and enter the subepidermal tissues. To protect these delicate tissues, melanization (increase in the density of melanocytes in the epidermis and the production of darker skin) would have proven very advantageous.

Nutrient photolysis of folate, mentioned above, is thought to have played an important role in natural selection and the evolution of darker skin colors. Folic acid is required for normal DNA biosynthesis, and folate (a conjugated form of folic acid) is required for bone marrow maturation and red blood cell development. Research has also shown a causal relationship between neural tube defects and folate lysis. In addition, tests on lab mice and rats have shown that folate deficiency can cause male infertility (by arresting spermatogenesis). Putting all of these clues together, it's reasonable to hypothesize that Homo ergaster individuals that had greater protection against UV radiation were likely to produce more offspring than those with lower concentrations of melanin, eventually leading to darker skin colors associated with tropical environments.

As populations spread from Africa, it seems likely that dark skin color was less well suited to environments with lower UV radiation levels in the temperate zone. While dangerous in excess, UV radiation is essential for the synthesis of previtamin D3, which is needed for calcium absorption and normal skeletal development. In tropical areas, there is no problem receiving enough UV light for D3 synthesis. In higher latitudes, though, where exposure to UV light is significantly less, a high concentration of melanin may hinder the passage of enough radiation to synthesize the necessary amount of the vitamin precursor. Medical records show that people with darker skin living in the higher latitudes are at greater risk for vitamin D3 deficiency (which can trigger the onset of various bone density diseases that can result in immobilization, deformities, and death). For this reason, it is believed that as populations moved north, natural selection favored lighter shades of skin. The point is that by understanding the biological benefits of traits, it is possible to understand the evolution of them.

In light of all this information, phenotypic diversity - the expression of different external traits in different geographic regions - probably has deep roots in human ancestry. Yet the historical pattern of geographic variation evident in modern humans has been around for only a very brief time. Humans have spread extensively over the past 50,000 to 100,000 years, much more so than in any prior period of human evolution. And as populations have extended to new continents, islands, and more extreme environments, humans groups have adapted in new ways and have interbred. Phenotypic differences among humans are thus many and diverse, and have been shaped and reshaped over the past 50,000 years - less than 1% of the evolutionary history all people have in common.