The Evolution Of Man Essay Research Paper

The Evolution Of Man Essay, Research Paper

The Evolution of Man

Ben Bader

Humans have existed on the Earth for approximately 3.4 million years. At least, that.s from when the oldest human ancestors have been found. The oldest known human is the fossil “Lucy,” an Australopithecus, discovered by Donald Johnson and M. Taieb. Australopithecines looked more like primates than modern-day Homo Sapiens; they walked semi-upright, they had low, sloping foreheads, protruding jaws, almost no facial expressions, thick body hair, and were about three feet tall. Over three and a half million years, humans have evolved greatly. We have grown from 3 to almost 6 feet, lost most of our body hair, become slender and adapted to walking, and grown brains over three times as large as the first Australopithecines. Besides all this, humans (Homo Sapiens) have developed an advanced material culture. Now, instead of living in trees and digging food from the ground with sticks, we live in vast cities of millions and buy our food from the local grocery store with money (another recent development). Humans have come a long way, from Australopithecus to Homo Sapiens. But we are also like the primates in many ways, too. We have the same basic body structure. Their hands are essentially just like ours, except that they don.t have opposable thumbs. Their feet are similar to ours, only with longer toes for gripping. And our faces are very similar as well. Nevertheless, we still have come a long way from living in trees to living in cities. Slowly, through hundreds of thousands of years, we mutated time and time again, natural selection ensuring that no harmful mutations continued. From the slow process of evolution, four distinct species emerged and died out, each giving way to its. successor: Homo Habilis, Homo Erectus, Homo sapiens Neanderthalesis, and finally, Homo sapiens Sapiens. We.ve come a long way over our brief (3.4 million years) existence on Earth.

The first major step leading to Homo sapiens Sapiens was walking upright, or becoming bipedal. The Australopithecines were the first to do this, albeit rather clumsily. Their gait was, judging by their bone structure, was unsteady at best, and they probably mainly were quadrupedal (walking on all fours). They also retained the ability to climb trees. The oldest Australopithecus fossil is Lucy, an Australopithecus Afarensis. Over 40% of her skeleton was found intact, making Lucy one of the most complete Australopithecus finds as well as the oldest. The Australopithecines had a brain about the size of an orange (400-550cc), prominent cheekbones, and heavily enameled molars. They were about three feet tall, and had small, underdeveloped thumbs. Their toes were also somewhat shorter than other primates. Australopithecines, while definitely possessing some human characteristics, were still much closer to the chimps and gorillas that we evolved from, so it is safe to assume that they lived similar lives to other primates. They probably, judging from arrangements of fossils at sites, lived in one place in small groups. It is assumed that, like gorillas, one male dominated a group of Australopithecines. We assume this because of their sexual dimorphism. Sexual dimorphism is a noticeable difference in the sizes of males and females in a species. It is usually the males who are larger; in the case of Australopithecines, the males were larger. We know they lived in groups because fossil groups of Australopithecines are often found with more than 5 individuals in the same place. One site had 13 dead in the same place. While Australopithecines are most likely direct ancestors of modern-day humans, they were still relatively unintelligent. Their tools, if any, were limited to sticks and rocks found on the ground. Australopithecines were vegetarians; even if they knew that animals were edible, they still had no reliable means of killing animals for food. That came with the evolution of Homo Habilis. About 2 million years ago, highly evolved Australopithecines made the fundamental realization that then can influence their environment; they made the first tools, began exploiting resources, and made the shift to Homo Habilis at the same time. Homo Habilis is the earliest known member of the Homo genus, and has been found only in Africa. Besides a brain size 50% larger than Australopithecus, Homo Habilis was taller, had an almost hairless face, and flatter nostrils. They were taller than Australopithecines, and were becoming omnivorous. Homo Habilis had, among other things, discovered that meat was edible. They began scavenging dead meat, and added it to their normal vegetarian diets. We know this because of their teeth. Homo Habilis had grown large incisors, just right for tearing chunks of meat. They also had grown wisdom teeth, or a third molar. They are also required for chewing meat. The most important development in Homo Habilis, however, is language. With their larger cerebral cortex, the had incredible (for the time) abilities in reasoning, thinking, and memory. They also hunted, which was a group activity requiring precision, accuracy, planning, and silence. Thus, instead of the grunts and shrieks of their ancestors, Homo Habilis probably developed hand signals and facial expressions which conveyed meaning for use in hunting parties; this was the first symbolic communication. These signals became more complex, and hand signals were developed t