Human Evolution: How Humans Differ from Other Species
GEOLOGISTS: provide us with a chronology (dating system) of prehistory. Their study of the
earth’s crust enables them to determine the approximate date of remains recovered from the
earth.
ANTHROPOLOGISTS: study fragments of prehistoric human skeletons to build up a picture
of what man was like in the distant past and how he has since changed physically.
ARCHAEOLOGISTS: excavate the sites of early man’s activities and obtain information about
the habits, customs, and tools of our prehistoric ancestors.
Theory of Evolution:
Charles Darwin: was a botanist who, on his voyage with the HMS Beagle, examined
species of animals across the world. Specifically, Darwin noted the Galapagos Islands.
Totally surrounded by water, the animals on the Galapagos Islands had no way of
coming in contact with their mainland counterparts, nor had they for hundreds of
centuries.
Darwin was surprised to see that the species on the Galapagos were similar but not
identical, to the ones on the mainland. Birds of the same species would look radically
different, and so on. The differences helped them survive more easily in their given
environments. For example, a Finch on the mainland would be green, to hide itself in
the green fauna (vegetation) it lived in. The same species of finch would be brown to
suit the different vegetation of the Galapagos. Both, however were undoubtedly finches;
their physical structure was too similar for them to be different species.
Darwin concluded that these adaptations had been changes brought about by mutation
advantageous to the environment. Animals born with advantageous mutations (ie.
Colours to give better camouflage against predators) survived and passed the mutation
genes on to future generations. Those without, died off. Darwin called this process
“Natural Selection”. He used this theory to account for apparent changes or evolution of
species through the centuries. For instance, Darwin connects the modern man to
Australopithecus.
In 1859, Darwin published On the Origin of the Species, in which he argued that all life
had slowly evolved. A few years later, in The Descent of Man, he focused on man, his
evolution and his relationship to other creatures. Darwin’s ideas provoked a storm of
controversy that has not yet fully subsided, and they have had a profound effect on all
areas of thought- scientific, social, historical, political, and religious. He was seriously
censured by the Church for his opposition to the Creation story of the bible and because
he said that man was descended from apes. However, Darwin never stated this. He
only said that modern man and modern ape has a common ancestor, but now they were
two different branches of the hominid family tree.
The following is a timeline that describes some of the different skulls and part skeletons
that have been unearthed in the recent past. The oldest in the timeline was
Zinjathropus- not ape-like enough to be called ape; but not man-like enough to be called
human. He is probably two million years old. A female named “Lucy” of a different
species, Australopithecus Afarensis, was found and is possibly three million years old.
She is the oldest hominid/ Australopithescene ever found. Other members include homo
erectus, the first of the species to have walked upright instead of bent over like an ape.
This is an important evolutionary feature. Next oldest is Homo Habilis, the handyman,
who has been found near sharpened flints presumably used for hunting, skinning, and
building crude structures. Neanderthal Man was found in Neander Valley in German and
has been dated as early as the last ice age. Neanderthal was said to be about 5 feet tall,
covered in hair and had a very low overhanging forehead. The next species to be
identified was Cro Magnon man, found in France. He is the inventor, and is credited with
the invention of the fish hook, knitting needle, sewing needle and thread, makeup,
jewelry, apartment dwelling, and a system of government which may have possibly
incorporated kingship. He resembled homo sapiens in his tall, upright posture, lack of
superfluous hair, and high, intelligent forehead. After him, Homo Sapiens appeared,
called Wisemen, because of his increased brain capacity and other evolutionary
advantages giving him domination of other species of animals on the planet.
How Do Humans Differ from other Species?
Humans belong to a biological group called primates, the highest order of mammals.
While we are not directly descended from chimpanzees or gorillas, we do share a
common ancestor. Evidence seems to indicate that the genetic makeup of primates and
humans varies by only 1 or 2 percent; we also share many physical and some social
characteristics. For this reason, physical anthropologists look to primates for clues that
may shed light on the evolution of humans and their behavior.
Among the more significant features we share with other primates are opposable
thumbs, which make it easier to manipulate objects, and we have three-dimensional, or
binocular vision that allows us to judge distances. We also share a highly developed
brain with a large capacity to learn and think, although humans obviously outperform
primates on this count. Socially, our children like those of other primates, remain
dependent for a long period of time and require a lot of care in order to learn and
develop into self-reliant, independent adults. Humans and other primates are social
creatures, depending on the group for survival; but we also share a capacity for
aggression and defense of territory. Anthropologist Jane Goodall recorded her
observations of a group of chimpanzees that divided into two communities. Over the
next few years, Goodall watched as one group attacked the other, killing isolated
individuals until the weaker group was exterminated. Goodall speculated that this
warfare may have been a fight for territory.
One trait that primates and other animals do not share is “bipedalism”, the ability to walk
upright over long distances, allowing humans to carry objects and perform tasks while
standing. In addition, humans have developed the ability to communicate complex and
abstract thoughts through language. Some anthropologists believe that this capacity for
language is what finally separates humans from all other species.
These unique and shared human characteristics combine in a a way that has enabled our
species to survive and prosper. Their importance is obvious when we observe the
behavior of young child. Children inspect the world around them, first by looking at
shapes and colours, then by reaching out to touch them. An inquiring mind, good
eyesight and adept hands provide powerful tools for understanding their world.
Human Diversity: Myth or Reality?
Anthropologists speculate that physical differences among human groups develop in
response to various climatic, geographical or cultural conditions. For example, over the
period of tens of thousands of years, skin pigmentation has changed according to
climate. Dark skin provides survival value in hot climates, since it is more resistant to
ultraviolet radiation. In colder climates, where the sun’s rays are weaker, lighter skin
captures more sunlight needed to produce Vitamin D. Anthropologists continue to study
how other physical variations developed.
The Myth of Biological Superiority
In the past, physical anthropologists used to divide humans into three distinct racial
groups, Caucasoid, Mongoloid, and Negroid, based on external physical characteristics.
Today, while the concept of race is still in common use, most social scientists question its
validity. In 2001, the human genome project revealed that every person shares 99.9
percent of the same genetic code, indicating that all humans have a common ancestor
and that variation among us is minimal.
Not only is the concept of race inaccurate, it can also be dangerous. For example, in the
nineteenth century, it was widely believed that certain races were superior to others.
Social Darwinists applied Darwin’s theory of natural selection to the social world and set
forth the doctrine of the ‘survival of the fittest’. They believed that those they considered
less intelligent, or less aggressive, would ultimately be replaced or conquered by those
they believed were fit to survive. This theory was used to justify the view that certain
races (and classes) were inferior to the others, and that their “superiors” had a right and
even a duty to dominate them.
Such ideas of racial superiority have often been used to justify exploiting and annihilating
peoples around the world, such as the Aboriginal people of North America; Africans who
were brought to North America as slaves, and Jews. In South Africa, the policy of
apartheid granted rights and privileges to individuals based on mainly on skin colour.
The Benefits of Diversity
Nowadays, reputable anthropologists accept that no group of people is superior to any
other- mentally, physically or morally. Most agree that all human beings are descended
from the same ancestor and that we share more similarities than differences. The
“success” or dominance of one group over others at a particular time or place is
considered to be the product of greater opportunities, education or other cultural factors,
rather than an indicator of biological or genetic superiority. Moreover, anthropologists
have found that diversity among humans has contributed greatly to the success of the
human species. If this millennium brings environmental changes, diversity may mean
that some people will have the physical traits necessary to adapt. These characteristics
may give future humans an edge that will allow our species to continue.