Answer:
Variation occurs in species with the genes resulting in the traits and physical characteristics that make it possible for them to be among the fittest for a number of reasons:
1. Mutation
2. Recombination and
3. Migration
Step-by-step explanation:
Mutations: A mutation is a deviation from the norm in a DNA sequence. It can be stimulated by errors during the DNA replication process which happens as the cell is dividing, or by exposure to ionizing radiation, chemicals, or viral infection (whether artificial or natural).
It is noteworthy that naturally, without any human intervention, the possibility of a spontaneous mutation is very low.
Recombination: This refers to the creation of new fusion of genes in the offspring that did not occur in the parents by the processes of crossing-over and independent assortment. Independent assortment meaning that the allele the gamete received for one gene was not influenced by the allele received for another gene.
Migration: Variation by migration here refers to the introduction of new genes from into one population by another. This could happen when a new population arrives at an existing one or when an existing one migrates to another population.
We can say for example that, genes from Americans have “migrated” into the population of African origin in America given the continuous immigration of Africans into America.
So in both populations, there are very fit species, but when their genes are mixed during cross-reproduction, variation arises.
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