Question

What is the ultimate source of variation needed for evolutionary change?

Answer 1

Hint: The evolutionary change depends upon the gene, the change in the allele of a gene caused by the change in DNA sequence which causes variation. The variation that causes is the sudden and unpredictable change that occurs due to genes.

Complete answer:
The mutation is the ultimate source of variation which leads to evolutionary changes. It is a sudden, unpredictable and inheritable change that occurs due to the changes in and genes. The mutation is divided into genomic mutation, chromosome mutation and chromosome aberrations. The genomic mutation caused by the change in the number of chromosomes. It may be polyploidy due to an increase in chromosome set number and maybe aneuploidy due to a change in the number of chromosomes by addition or subtraction. The increase in the number of the same sets of chromosomes or same genome is known as autopolyploidy and an increase in the chromosome set due to aggregation of the chromosome from two or more organisms are known as allopolyploidy.
The gene mutation is the change in the gene structure, in this, all gene mutates and the frequency of mutation varies from gene to gene which gets increased by radiation and mutagens.
The chromosome aberrations bring change in the morphology of chromosomes by deficiency, duplication, inversion and translocation. The mutation is the replacement of alleles removed by the agent which shows evolutionary changes.

Note:
Evolution occurs due to the change in the gene pool because the gene pool is not static and it shows changes in the frequency of genes and number of genes because it is an aggregate of all the genes present in the populations.