Theories of Evolution

The process evolution is interpreted in many different ways by scientists and philosophers of the world. Before the different theories put forth by scientists, origin of life was just a matter of predictions. The scientists that preceded Charles Darwin provided descriptions about various species, however, nobody presented a clear idea about the human evolution or evolution of living beings altogether. Most of the philosophers and people in general believed in the 'creation theories'. With the development in the field of genetics, the evolution theory proposed by Darwin too is under scrutiny.

Pre-Darwinian Theories
The pre-Darwinian era saw the contributions of notable personalities like Carolus Linnaeus, John Ray, Erasmus Darwin, George Cuvier, etc. in the study of evolution.

Carolus Linnaeus is known for his contributions in the field of taxonomy. He designed the system of binomial nomenclature. Using this system he tried to name the different living beings in the framework of a 'genus' and a 'species'. The genus and species were however, only the lower levels of the big hierarchy of the taxonomic system of living beings. Mr. Carolus Linnaeus didn't see the natural world from the point of view of evolution. His belief in God made him think he was just unraveling the order of life created by God.

Darwin's Evolution Theory
The backbone or the crux of the Natural Selection theory proposed by Darwin was the existence of a common ancestor for the development of subsequent species. According to this theory, living beings initially originated from non-living things. The early living beings which are simple in their form, give rise to complex organisms over time. The changes that take place in the organisms during their development could be the result of adaptation to the surroundings or because of sudden genetic changes known as mutations. According to this theory, the beneficial genetic mutations are carried forward by the organisms. They help in the survival of that particular species. The adaptations or changes are handed over to the next generations which only makes them stronger. The organisms that are unable to adapt to the surroundings or develop beneficial mutations, are either wiped out in the process of evolution or they remain suppressed. The phenomenon of 'survival of the fittest' is supported by the natural selection theory. Survival of the fittest denotes the ability of an organism to overcome the hurdles and hindrances in order to survive in the process of evolution.

The theory proposed by Jean-Baptiste Lamarck was based on the concept of 'inheritance of acquired characteristics'. According to Lamarck's evolution theory an organism alters the body organs in order to adapt to the surrounding environment. The adaptations are carried forward to the next generations. The example of the giraffe's neck can be considered to study Lamarck's evolution theory. According to this theory, the giraffe is known to have outgrown his neck in an effort to adapt to the environment. The long neck of the giraffe indicates that the giraffe had to struggle to obtain food from tall trees initially. However, over time the neck elongated and the subsequent generations of the giraffe inherited the characteristic.

More and more facts will unravel, with the development of science. The speedy development in human genetics, and genetics as a whole, has opened new vistas for the study of evolution. The study of genome of different organisms will bring into light the truth behind the evolution theories we are studying till date.