Table of Contents
Introduction
The word ‘evolution’ was first mentioned in the book ‘The Origin of Species’ in 1859, by Charles Darwin. Darwin put forward the concept of evolution during his journey to the Galapagos Islands. He noted that all living species change both their physical and anatomical structure over a long period of time for better adaptations to the developing environment. The difference is by natural process and the species which do not get adjusted will find it difficult to survive. This was the proposed concept of natural selection and Darwin called it ‘Survival of the fittest.
Biological Evolution
Evolution is a scientific theory mainly used by biologists to explain how living species change their characteristics for their better adaptations to the changing environment. It is the successive adjustment of inherited traits over a huge span of time, usually over generations. Researchers consider it as a process as well as the outcome of a process. Evolution as a process explains how the world came to exist. Sometimes it is explained as the outcome of various processes which resulted in biodiversity. Natural selection is one among them. Darwin’s concept of evolution is natural selection. Darwinian Theory of Evolution explains that evolution is the result of natural selection, and natural selection is biased by the inherited characteristics of organisms. The adaptive ability of organisms is the one which helps organisms in evolution through natural selection.
According to Jean-Baptiste Lamarck – a French naturalist, he explained evolution is all about the law of use and disuse by the organs. He also explained that the characteristic feature of certain living creatures such as giraffes, and the long necks, is the result of their adaptation to their nature. The elongated necks are the outcome of their attempt to feed leaves on tall trees. This character is passed on from generation to generation.
Also Read: Foster’s Rule
Natural Selection and Genetic Drift
According to Darwin’s Theory of Evolution, branching descent and natural selection are the two factors for evolution. Environmental factors like climate, temperature, availability of resources, etc. had a great impact on the evolutionary process. Suppose a colony of bacteria is growing in a medium A. They feed on, reproduce and find themselves fit for that particular medium A. If you change the composition of medium A to B, every bacterium wouldn’t make it. Only a portion, which can adapt to new conditions, will survive in medium B. Eventually, they separate out and arise as new species. Here, the nature of the medium filters the fittest and marks an onset for evolution.
Another factor which can lead to natural selection is inheritance. Two organisms compete for the same resource. If one can multiply much faster than the other, it will dominate over the other. Thus, the inherited gene in organisms helps them in getting selected and evolve. In other words, the more you adapt to the changing environment, the more chance you have to get selected by nature.
The inadequate climatic changes, natural resources, predators, competition, etc., are amazing challenges given by nature to select the fittest. The one which has more inherited adaptations will have more chances of survival and others won’t flourish. The one which is selected by nature grows, reproduces and a new population will arise at the cost of others. Thus, we can conclude that during the course of evolution there is ‘survival of the fittest.
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