Natural selection

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Natural selection is a process where individuals better suited to their environment survive and pass on their traits to offspring, in turn making the trait more popular in the gene pool. Natural selection is also one of the many processes by which evolution occurs[1].

Suggested by Charles Darwin in 1859, the proposal has been revisited and adjusted accordingly, more frequencly encorporating genetic concepts. He argued that the process rests on two universally true concepts: 

  1. Organisms overproduce and have more offspring than those who will survive and reproduce and
  2. Organisms have variation and different abilities to survive their enviornment which may be linked to the individual's genotype[2].  

In order for natural selection to take place there must be variation in genotype ,typically caused by a random genetic mutation.Varied genotypes produce varied physical characteristics, making individuals distinguishable (Phenotype) this means some organisms are better /or worse adapted to their environment. Organisms that are better suited to their environment have higher percentage chance of survival, for example; in the artic circle a hare with white fur genotype is less likely to be eaten by predators, a hare with brown fur genotype is more likely to be visible to predators therefore more likely to be eaten. White hares are able to survive and reproduce passing on the white fur allele to offsping. As time passes frequency of the advantageous allele increases in population and the disadvantage allele falls[3].

References

  1. Hartl DL, Ruvolo M. Genetics: analysis of genes and genomes, 8th Ed, Boston: Jones and Bartlett, 2012
  2. Hartl DL, Ruvolo M. Genetics: analysis of genes and genomes, 8th Ed, Boston: Jones and Bartlett, 2012. Pg 646
  3. University of California Museum of Paleontology. Natural selection. [cited 04/12/2016]. available from: http://evolution.berkeley.edu/evolibrary/article/evo_25


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