Abstract
The Darwin’s theory of natural selection best explains how some of the existing species have evolved over the years to what they are today. Natural selection entails a number of factors that affect genes, both in a positive way or negative way, causing changes that lead to the existing structure. This paper has given examples, or rather evidence of the Darwin’s theory, which has been received with both appreciation as well as critics.
Introduction
Natural selection is the mechanism that species use to evolve and possess genetic adaptations to the environment. The process is known as evolution. Many theories have been formulated to explain how have evolved to what they are, and the most popular of them is the Darwin’s theory of Evolution.
How natural selection has influenced the evolution of the hominidae species
A good example of how natural selection influenced and still influences the evolution is that of the hominidae. Natural selection favored and still does favor the genes, making the survival and reproduction of the species easy. The genes usually are blueprints for proteins and once there is a chance of positive natural selection, some changes occur to the sequence of the amino acids in the protein. More to that, natural selection positively favored the genes of the immunity system, reproduction system, as well as the nervous system. The changes slowly led to the evolution of the ape-like creature to what we have today as the human being. The evolution that is still taking place has reduced the differences between the human being and chimpanzee today.
Scientific evidence of the Darwin’s theory
The best scientific example of evolution due to natural selection, in support of the Darwin’s theory is the evolution of the ape-like structures to the human being, better known as the evolution of the Hominidae species.
To support this theory is the high level of resemblance between the skeleton structure of the apes and that of human beings. This does not carry much weight. However, studies have shown how the human being revolved from the ape-like structure to what he is today through a number of stages.
The stages named as follows:
- Ardipithecus ramidus- earliest of the fossils. Was bipedal, about 4 feet tall, and a forest dweller.
- Australopithecus anamensis- was also bipedal.
- Australopithecus afarensis- had a brain capacity of 450cc and was fully bipedal.
- Australopithecus africanus- was bipedal, but larger in size. Had brain size of 500cc and was herbivorous.
- Australopithecus aethiopicus- had massive chewing muscles. Brain size was 500cc.
- Australopithecus robustus- had a huge face but no forehead. The brain size was up to 525cc.
- Australopithecus boisei- more massive face and had huge molars.
- Homo habilis- better known as the handy man.
- Homo erectus- brain size was up to 900cc and had developed some form of speech.
- Homo sapiens- brain size was up to 1200cc, had speech, and the skull is more rounded.
- Homo sapiens neandertalensis- brain size of 1450cc, and much stronger than the modern man.
- Homo sapiens sapiens-this is the fossil closest to the modern man and the fossil first appeared more than 12000 years ago. Has an average brain size of 1350cc.
Conclusion
The Darwin’s theory best explains the evolution of man. This is because there is tangible evidence that can be relied on to back it. More researches and studies are being carried on and so until a better theory is found, this one remains as the most concrete one.
References
Darwin, C. (2008). On the Origin of Species: by Means of Natural Selection or, the Preservation of Favoured Races in the Struggle for Life. London: MobileReference.
Diane Alford, J. H. (2003). Excel HSC biology. Australia: Pascal Press.
