What's the difference in meaning between "variation" and "alteration"?


I am studying biology. While studying I have come across this paragraph:



Mutation is a phenomenon which results in 'alteration' of DNA sequences and consequently results in changes in the genotype and the phenotype of an organism.In addition to recombination, mutation is another phenomenon that leads to 'variation' in DNA.



Can anyone explain the difference between using alteration and variation in this paragraph?



Answer



By alteration, they mean a change in the DNA of a single organism. An alteration to one organism makes its DNA different from other organisms in the same population. Variation is the range of differences in a population. If all the organisms in a population are very similar, variation is low. If some organisms in a population are quite different from others, variation is high. Over time, mutations increase variation. Natural selection reduces variation.


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