In 1859, Charles Darwin published a controversial idea that all living things had evolved through a process of natural selection. As a result, Darwin created a topic that everyone has an opinion on one way or another. Are humans created by a divine being who watches over us or are we a culmination of evolution by the impersonal mechanism of natural selection. Over time scientists have continued to scour the lands for fossil records in an effort to help determine the answer to the question.
When discussing evolution, one important aspect of the theory is speciation, which is the separation of one species into two different species. Basically it is the point where two groups within the same species are no longer able to interbreed. Experts believe the pool of human genes and chimpanzee genes split from a common ancestor source sometime between 3-7 millions years ago, while the pool of gorilla genes had branched off from the common source years earlier. In order for the specialization to occur, the three different pools of genes had to become geographically separated, which would allow them to be enhance by their different environments, causing each species to evolve into their modern day equivalent.
This is where scientists have begun to search for the missing link, the earliest hominids who were the first to walk upright on their two feet.
There have been two discoveries in the recent years that have helped scientists gather more information on the evolution theory and locate the missing link. Both fossils records have been discovered in the East African Rift Valley which splits through Ethiopia, Kenya, and Tanzania. The first discovery occurred in 1974 when Australopithecus Afarensis or "Lucy" was discovered. Scientists have estimated Lucy lived from 3.6 to 3.2 million years ago, though her discovery has resulted in more controversy. With only 40 percent of her skeleton intact, there have been debates whether she was a true biped and whether she was an actually female or even a male.
The second and most compelling discovery came in November of 1997, at a fossil-rich site discovered in a dry valley bordering the Middle Awash River of the Afar region in Ethiopia. The excavation team led by paleoanthropologist Tim White, a professor of integrative biology at the University of Berkley, discovered the fossilized skulls of two adults and one child. The skulls were dated at 160,000 years; making them the oldest know fossils of modern day humans. The characteristics of the fossils and the comparisons from the modern day humans came from the worldwide sample of skeletal remains at the University of Berkley.
The fossil date precisely from the time when biologists using genes to help chart human evolution. These fossils have helped to fill a major gap in history of human record, an era which began when facial features and brain cases we recognize today as modern day humans first appeared. Prior to this discovery, there has been a lacking of intermediate fossils between pre-humans and modern humans.
While completing their research, the team unearthed several skull pieces and teeth from a handful of other hominids individuals, along with numerous stone tools, including hand axes and flake tools. This evidence has helped show these early hominids used various stones to help with their daily activities of hunting and gathering.
Because the fossils represented a transition between the more primitive hominids from Africa and modern humans, they provide compelling support for the hypothesis that modern humans evolved in Africa before they spread out to other continents. This evidence supports the theory posed by molecular anthropologists who have been saying modern humans evolved out of Africa.
This is contrary to the belief that modern humans began in the areas of Europe from other hominids that had migrated out of Africa at an earlier time in history. These new findings are older, well-dated, and more compete without sharing the characteristics of more primitive human ancestors like Homo erectus and Neanderthals, who are believed to extinct as this time in history.
Though many feel this clear fossil evidence show the rise of modern day man though evolution, there are some who point out the inconsistencies in the research. The fossils discovered were only 70 percent complete and the skulls were not attached to the other bones located at the research site. Despite the debate, researchers continue to search for more fossil evidence to help prove without a doubt as to the origin of modern day man.