Human races

Introduction

This chapter looks at the different divisions of the human species, called races. It will also discuss different human ancestors. It will look at the roles of humans' genotype (genetic makeup) and their environments in the process of the evolution of races.

Human ancestors

Millions of years ago, when different types of mammals had established as species, some primates came down from the trees to explore new habitats like woodlands and savannas (tropical grasslands with scattered trees or shrubs). Some of them started walking on just two legs instead of four. New forms of primates started to evolve.

Human evolution is part of Darwin's theory of evolution. It is the process of change by which human beings emerged as a distinct species. Here are some terms commonly used with regard to human evolution.

Hominids are all primate human ancestors. They include all modern and extinct apes. An ape is primate with no tail. Apes include humans, chimpanzees, gorillas and orang-utans.

Hominins are modern humans and extinct human species. Extinct human species include all our immediate ancestors (including members of the genera Homo, Australopithecus, Paranthropus and Ardipithecus).

Australopithecus isagenus of fossil hominid that lived between 4.2 million and 1 million years ago. He had a small brain, a large face and teeth and he walked on two legs.

Paranthropus is an extinct genus of bipedal hominid that probably descended from Australopithecus. The main difference between Australopithecus and Paranthropus was the size of their brain. The size of Paranthropus's brain was less than half the size of the brain of modern humans.

Ardipithecus is another extinct genus of hominid. His teeth and face structure were very similar to Australopithecus'.Some scientists consider Ardipithecus to be on the chimpanzee rather than human branch.

Homo is a genus of hominids characterised by a large brain. This genus is divided into the following species: erectus; habilis and sapiens. It is also the genus to which modern humans belong. Another important characteristic of Homo is their dependence on culture.

Changes in food and habitat led to changes in the activities of hominids. Changes in hominids' activities led to changes in the size and capacity of their brain. See image 1.

Modern human species

Biologically, all modern humans are classified as a species called Homo sapiens. 'Homo sapiens' means 'knowing man' in Latin. It is the only surviving hominin. Compared with other hominins, Homo sapiens have the largest brain. See image 2.

Humans are very different from other primates. In the process of evolution, humans learned how to walk upright on two legs. Our pelvis, hip and leg muscles and an s-shaped instead of c-shaped spine make that possible. Compared with other primates such as chimpanzees and gorillas, humans have a differently-shaped face, nose and teeth. Also, all humans have a long infancy and childhood, developed speech and a very complex social structure. The most important difference between humans and other primates is the ability to think abstractly, meaning that we can think about something without looking at or dealing with the subject of our thoughts. Humans have also developed the ability to make and use complex tools.

Origin of human races

Modern humans are a very diverse species, exhibiting a high degree of phenotypic, variation which means that we come in many shapes, colours and sizes. Humans also have a wide range of physical and behavioural characteristics. See image 3.

According to fossils, modern humans first appeared in Africa. One group remained there, while at least one other group migrated out of Africa and evolved into all non-African populations.

One of the most noticeable phenotypical human characteristics is natural skin colour. The body pigment, called melanin, defines the colour of our skin. But melanin does much more than simply provide our body with pigmentation. Its most important role is in protecting the body by absorbing ultraviolet (UV) radiation from sunlight that falls on the skin. UV radiation can damage the skin and produce skin cancer if not filtered out by the melanin. Generally people with darker skin can better adapt to areas with a hot climate, because melanin is a very good sun block.

Also, according to scientific research, different races have different metabolic rates. Humans need fewer calories to survive in hotter areas. So, colder climates contributed to the formation of human populations with a higher metabolic rate.

The strong winds of some Asian areas, like Mongolia, might have been the cause of the almond-shaped eyes of Asian people. According to Darwin's theory which states that natural selection is survival of the fittest, people with almond-shaped eyes who lived in these areas probably had fewer eye infections caused by the strong winds.

All the above-mentioned statements are just speculation regarding the origin of human races. Many human populations of the world have distinctive features of different races, the origin of which still cannot be scientifically explained. The combination of different environmental factors and a human genotype played the most important role in the formation of diverse, modern human communities.

What is a human race?

A race of people is defined as a group of people with certain common, inherited features that distinguish them from other groups of people. The theory of the origin of human races has always been a very controversial subject that has been strongly influenced by politics. Scientists are still arguing about the number of human races today. Based on current biological concepts, there are four main human races:

Caucasoid (or Caucasian) usually refers to people who originated in Europe, North Africa and the Middle East

Mongoloid refers to people who originated in East Asia as well as Malaysians and American Indians.

Negroid refers to people with dark skin who originated in Africa.

Australoid refers to the Aboriginal people of Australia.