Human Evolution and Adaptation

Path that humans took/Other paths

Before the Holocene, pre-sapien creatures roamed the earth. Human evolution started out with early primates, which then divided into two groups: the prosimians and the simians (or the anthropoids), prosimians being the more primitive of the two. This group includes lemurs, traisers, bushbabies, etc.

Early primates appeared at the end of the Cretaceous Period. Starting in North America, they soon spread all over that continent, and Eurasia, too (these two continents were still connected). From Europe they reached Africa. Only a few species of monkeys made it to isolated South America during the Oligocene. Nobody got to Australia.

These primitive primates (say that fast a few times!) eventually evolved into Dryopithecus, the father of apes, during the Miocene. Originally, it was thought that these apes would give rise to sapiens, but later it was evaluated that homonids branched off before dryopithecenes appeared.

Ah, but now, the stars of the show: US!

The scene is 14 million years ago. The place: the area near modern Kenya. Ape-like creatures are running around on two legs. They have come down from the treetops (where all the primates used to spend their time) and became bipedal. They are called Ramapithecus. Their faces are Chimpanzee-like, but their teeth are more like human's. They had many ape-like features too. But when the cold came at the end of the Pliocene, and jungles changed to forests, and forests to savannas, Ramapithecus was unaffected.

Let's now zip ahead in time: Three million years ago, another ape/human being roamed Africa. Australopithecus Africanus, as it is now called, was much more like modern human kind. It definitely was upright. We can deduct this from the shape and size of Australopithecus' pelvis. Another piece of evidence that proves this, is its neck. Australopithecus Africanus had its head balanced on top of the neck, while other apes heads tilted forward from walking on all fours. Australopithecus' limbs were more like ours, too.

Teeth of Australopithecus are similar to those of modern humans, but the jaws projected from their faces. That made them look like apes. Another ape-like feature was the size of their brains. It measured only 500 cubic centimeters (modern humans' brains have a volume of 1300 cubic centimeters. Australopithicenes used tools. They used sticks and stones to break preys' bones, but they didn't actually make their tools.

Scientists found Australopithecus africanus bones in 1926. Then they started finding bones from many different species. Soon, they found fossils of a creature of a much heavier build. Once they named it Australopithecus robustus, they moved on. Another species found was called "nutcracker man," and is known scientifically as Australopithecus boisei.

Another, more slender species, was found buried with hand-carved stone tools! The size of its skull showed a greater brain capacity. This was the link between Australopithicenes and modern humans. It became known as Habilis (handy man), but there is controversy to its name. Some scientists prefer to call it Australopithecus habilis (handy-southern-human-like-apes).

1 million years ago, our ancestors had spread all over the Old World, and were now "true" humans. Known scientifically as Erectus (human that walks upright), this species has two specimens that stand out in particular.They are known as "Java man"(found in Java) and "Peking man"(found in Beijing). Each of these showed a significant increase in brain size. habilis' brain size was 600 cm ³, while Java's was 800 cm³ and Peking's was 1000cm³!

Neanderthals (discovered in Neander Valley, Germany) came after Erectus. They were even more advanced, but had to compete with another group of humans, Sapiens. Eventualy, Neanderthals dissapeared, and Sapiens ruled the earth. Homo Sapiens (Intelligent Human) evolved into the modern Sapiens Sapiens (Really Intelligent Human). They had now covered the earth and flourished in their glorious civilizations, made and viewed webpages, researched their evolution, and read all about the history of their planet.

Description of Humans (Part 2)