The Theory Of Evolution By Natural Selection

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The theory of evolution by natural selection proposes that all species are related (Eade, S. and profile, V. 2014). There is estimated to be between 6 million and 100 million different species in the world, with more species undiscovered than those discovered; this is all owing to the concept of evolution (Borenstein, S. 2014). Evolution is defined as the “change in the characteristics of a species over many generations (Linstead, 2012).” The most widely accepted theory of evolution is natural selection, which is the “process where an environmental factor acts on a population and results in some organisms having more offspring than others (Linstead, 2012).” Other forms of selection include artificial selection, which occurs when people…show more content…
These successful genes are inherited by the offspring in order to recreate another healthy generation of species (Biology Online, 2014). However, natural selection will alter overtime due to selective pressures meaning that particular characteristics will only be favourable for a certain amount of time as species can evolve to suit more successful features.

There are three main scientists whose works contributed to the now-orthodox theory of natural selection; Jean-Baptiste Lamarck, Charles Darwin and Alfred Russel Wallace.

Jean-Baptiste Lamarck

Lamarck (1744 - 1829) was a French Biologist with a thorough knowledge of medicine and botany. He also recognised the similarities of species and came to the assumption that “life was not fixed (Florida State University, 2014).” He developed the first comprehensive theory of evolution (Wagner, J. 2013). He continued to contribute to the cell theory and suggested an alternative evolution hypothesis based on “acquired characteristics”. His mechanism was open-minded; believing that organisms had an “obsession to be perfect (Unknown, 2011).” When environments modified, organisms needed to alter themselves in order to survive. It was believed that if beings continued to use an organ more than they had previously, it would increase in size throughout its lifetime and vice versa (Strickberger, M. 2014). Lamarck applied this theory to giraffes. He assumed that a “nervous fluid” would flow into
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