- All living creatures exhibit traits which are either similar to some primitive or some advanced forms of living organisms on the earth. This phenomenon is known to occur within a class or species or sometimes in a broader group of classification. This transformation in forms and shapes is attributed by researchers, to environmental causes. And that it may take comparatively smaller durations of time to hundreds of thousands of years for such changes to set in. With time, some major natural causes have been instrumental in bringing about changes in habitats which correspondingly brought behavioral and somatic changes in living organisms on the planet.
- Biologists and research scientists, since the seventeenth century, have worked on the theory that life on earth started as a simple monocellular organism and evolved, over time, to a plethora of complex and elaborate multicellular, multi organ and multi species The study of evolution, which originally started as a study of origin of life ultimately centered on its diversification and transformation since inception. But as is a practice, and a healthy one at that, this theory of evolution too got its share of rebuttal from conservative quarters.
- Charles Darwin, the propounder of evolutionary theory, along with other contemporary biologists, after years of investigation and analysis of changes in life forms and the effect of changing natural environment on them, concluded that the present day life on earth has evolved by continuous progressive change by natural causes and is governed by environmental conditions.
- Darwin, as also the likes of Alfred Wallace, were initially silent on their discoveries for the fear of repercussions from a conservative society. Pre-Darwin theories did not believe in evolution and the contemporary scholars mostly testified theories being propagated by religious protagonists. Evolutionary theory, which mainly rests on the concept of ‘Natural selection‘, faced flak from such theorists. Darwin and Wallace convincingly portrayed with case studies that because of evolution, the characteristics which were important for survival, developed in organisms over numerous generations. This variation in characteristics was inherited by succeeding generations, though at times acquired randomly too. Finally, evolutionary theorists came to conclude that over the ages simpler life forms gave way to more complex ones and newer attributes were generated as a result of acclimatization to new environmental conditions. And that while newer attributes were appended, some defunct ones vainly subsisted.
- Later discoveries with regard to genetics, wherein Gregor Mendel did extensive research on inheritance of characters and mutation in genes, substantiated evolutionary theory and justified Darwin’s concept of ‘Natural selection‘ to a large extent.
- Sewall Wright, an American scientist, inferred from his findings that random variation in genetic structure of populations occurred purely by chance and that the features thus attained lived on with further generations. He named this peculiarity as ‘Genetic drift‘, which again complemented Darwinism.
- The evolution theory also came to be accepted for the fact that those who opposed it, just debated with arguments rather than producing and showing authentic laboratory results. The antagonists just kept looking for gaping holes by citing an odd example now and then. Some such statements to disapprove of the evolution theory were; why did human race in the equatorial regions have darker skins and people living in northern cooler climes have fairer skins and if ‘Natural selection‘ were to be true then the result should have been opposite. Also a major disagreement was the possibility of a simple monocellular organism having transformed into an enormous setup producing sixty thousand proteins of hundred different configurations.
- But with the advent of new age developments and lack of scientific evidence to support earlier theories about origin of life, Darwin’s theory of evolution came to be accepted as the most trusted school of thought.
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