Darwin proposed a theory to account for the forces behind the change; as the environment changes or an individual moves to a new environment, new traits are needed to ensure survival. New genetic combinations produce adaptation, and the individual who best ‘fits’ the environmental niche will survive through the process of natural selection “Survival of the fittest”.
The process of natural selection does not occur through the conscious state of the mind but through selective pressure.
For this theory to work it is based on five major assumptions:
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Variation: Individuals that differ form other members of their species in their physical characteristics and in their behaviour.
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Heritability: Some of the variation that occurs in a species is inherited. As a result of this the offspring tend to resemble their parents characteristics and mannerisms, rather than resembling that of the other members of the species.
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Competition: The members of most species produce more offspring than can survive. However, animals compete for things like mates, food and places to live. Those individuals who lose the competitions are less likely to reproduce.
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Natural Selection: The individuals who survive the process of competition and go on to reproduce will tend to have the characteristics that are better suited to the environment, than those who do not. Thus providing us with the initial explanation to natural selection or “survival of the fittest.”
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Adaptation: As a result of the process of natural selection, successive generations will tend to be more and more adapted to their environment. These animals will possess the characteristics that will improve the chances of survival and increase their ability to obtain food and most importantly reproduce. Suppose that a speedy predator eats only the members of a particular species. If only the fastest-moving members of the prey species survive, then that species should evolve over the generation on the direction of becoming on average faster moving.
Its major argument is that plant and animal species continue to exist according to how well they adapt to the environment.
Darwin was greatly influenced by the work and studies of Malthus.
Thomas Malthus, (1766-1834), a British economist, in 1798 published his Essay on the principle of population, a pessimistic study warning that population growth, which is geometric, will eventually outstrip food production, which grows arithmetically. His theories influenced the work of Darwin in the line of reasoning that led to his principle of natural selection and the survival of the fittest.
Malthus and Darwin were both pessimistic about the chances of any species showing reproductive restraint. As a result of this, Darwin reasoned that what must happen is that there will be ever-increasing competition for the finite resources. Competition exerts selective pressure because those who lose, when resources are limited, fail to reproduce.
The Theory of Evolution is relevant to the study of psychology as without a relevant hypothesis of evolution (change over time). There would be no analysis for psychology itself.
