Evolution is the variation in inherited traits of a population from one generation to the next. When populations of a species migrate to new environments, their genetic makeup changes, in order to suit their new environments. Some species manage to adapt and survive, passing their traits to the next generation while others fail to adapt and become extinct. This is called the process of Natural Selection as proposed by Charles Robert Darwin in his book Origin of Species (Reeder, 1995).
It can be explained, with respect to Charles Darwin’s theory of evolution, the existence of four closely related species of lizards originating from a single ancestry. Whereby, according his theory based on the process of natural selection, there existed one ancestral lizard species which then migrated into a new isolated habitat. This lizard species changed in order to adapt and compete for scarce resources in its new environment. Thus forming new traits whose usefulness, were passed to the next generation. Hence a new species was formed (Reeder, 1995).
This pattern of evolution is known as Adaptive radiation. If this pattern occurred more than once in different environments, the occurrences of more than one species can then be explained. Thus the existence of four closely related species of Lizards (Reeder, 1995). Variation between the species can be seen in their bone structure formation, complexion and length of tail.
Darwin’s process of natural selection is composed of four main components (Reeder, 1995):
• Variation: organisms from the same species exhibit individual differences in appearance and also behavior.
• Inheritance: some of the traits (heritable traits) are however consistently passed on from the parent to the offspring while the newer ones are strongly influenced by the environment.
• High population growth rate. Most populations have more and more offspring over time leading to straining of the available local resources leading to a struggle.
• Differential survival and reproduction. Those populations that have natural traits well suited to exploit the available local resources will produce the biggest offspring over time.
References
Reeder, A. (1995). Darwin’s Theory on Evolution. Retrieved October 27, 2012 from http://bioweb.cs.earlham.edu/9-12/evolution/HTML/theory.html
