The theory of human evolution says that the humanity evolved from primates, or ape, as their ancestors. According to scientific research, all mammals evolved from protomorphic reptiles in the Triassic Period, about 200 - 245 million years ago. When the dinosaurs had undergone extinction during the terminal Cretaceous, the mammals remained as the surviving groups, adapted accordingly in the Tertiary Period. The majority of mammals evolved in this very period, including the Primates, relative to humans.
There are two hypotheses, concerning the origins and evolution of today’s humans, Homo sapiens, both based on the assumption that our species evolved from Homo erectus, a Homo family tree species, which were renowned for being the first human ancestors to walk upright. The first hypothesis is the Out-of-Africa hypothesis, which states that the immediate predecessors, Homo erectus, inhabited Africa and continued developing into Homo sapiens, and started leaving Africa some 100000 - 200000 years ago. Homo sapiens superseded the whole population of Homo erectus, which stands for the idea that the humanity nowadays is descended from a certain event of speciation in Africa and has a high level of genetic identity, which is actually supported by several DNA studies of mitochondria. The second hypothesis, the Regional Continuity Hypothesis, suggests that Homo sapiens developed as a result of interbreeding between regional populations of Homo erectus, compounding further, which resulted in evolution of the four major races, inhabiting the today’s world.
All in all, it should be outlined that there are several points of view on the human evolution and although considerable evidence has already been gathered, a clear picture of the evolutional history has not been yet compiled. Study of this issue is to depict, how closely connected Homo sapiens are with other species.
References
Farabee, M. J. (2010). Human evolution. ATP and biological energy. Retrieved from http://www.emc.maricopa.edu/faculty/farabee/BIOBK/biobookhumevol.html
Langseth, J. (2005). What is human evolution? Retrieved from http://www.mnsu.edu/emuseum/biology/humanevolution/humevol.html
Smithsonian Institution’s Human Origins Program. (2010). Human evolution evidence. Retrieved from http://humanorigins.si.edu/evidence
