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Darwinian theory of natural selection

May 13, 2024 | by Bloom Code Studio

  • Darwin-Wallace theory states that “The change in species by the survival of an organismal type exhibiting a natural variation that gives it an adaptive advantage in an environment, thus, leading to a new environmental equilibrium, is evolution by natural selection”. 
  • The natural selection process is a continuous process of trial and error on an enormous scale for all living matter.
  • Natural selection includes the following five elements (factors or causes of natural selection). 
  1. The universal occurrence of variation: 
  • Every group of organisms (animal and plant) may differ in many ways, known as variation. The Darwin and Wallace period did not know the source of variation and assumed it might be one of the innate properties of the organism. Still, now we know that inherited variations are caused by mutation.
  1. An excessive natural rate of multiplication:
  • Without environmental checks, every species has great reproductive potential (reproductive rate tends to increase geometrically). If all the species remained alive and reproduced, it would soon be challenging to survive, obtain food, and crowd all other species from earth.
  1. Struggle for existence:
  • There is an interspecific or intraspecific, or environmental struggle for survival (competition for food, mates, space, and as well as survival in drought or cold).
  1. The consequent elimination of the unfit and the survival of only those that are satisfactory adaption:
  • Some of the variations shown by living things make it better adaption for them to survive; others are handicaps that bring about the elimination of the possessors. The core of the natural selection theory is the idea of the survival of the fittest.
  1. The inheritance of mutations or recombination that make for success in the struggle for existence:
  • The individual who survives will give rise to the next generation, and with this method, the successful variations are transmitted to the succeeding generation.
  • A less fit individual is eliminated before being reproduced.
  • Successive generation becomes better adapted to their environment. If the environmental condition changes, further adaption occurs.
  • The operation of natural selection over time in many generations may produce descendants (different from their ancestors). This way, two or many more species may arise or produce from a single ancestral stock.

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