Often in reproduction, broken chromosomes are formed by random natural factors.
When these combine with other chromosomes, new characteristics can be formed which are different from the Natural Chromosomes.
Mutations. These have quite a few different causes. Sexual reproduction is a "more recent source" {beginning 600 million years ago} of genetic variability. The process of sharing genetic information, coupled with the random crossing and mixing of genetic information during the creation of a new organism, leads to another source of genetic variability.
mutation
Sexual reproduction.
mutation
mutation
mutation
The ultimate source of variation is mutation. However, recombination, or crossing over, can produce enormous amounts of variation by shuffling alleles into different combinations. Combined, the two processes produce the variation upon which natural selection can act, and which results in evolution.
The most important source of variability in bacteria is mutation.
Independent assortment of chromosomes, crossing over and Random fetiliztion
plants are not the ultimate source of energy. It is the sun which is the ultimate source of energy to this planet
the mutation can be a sources of genetic variety.
Both of the following are correct: They have extremely short generation times and large populations; They can exchange DNA with many types of prokaryotes by way of horizontal gene transfer.