Theory:

Human Evolution involves the gradual changes from basic to more complex forms. Humans are believed to have developed from simpler forms.

Evolution is the outcome of the following five processes:
  • Mutation
  • Genetic Recombination
  • Chromosomal Abnormalities
  • Reproductive isolation
  • Natural Selection
Mutation:
A change in DNA is known as mutation. A DNA change in any organism can cause changes in many aspects of life. Mutation is an essential need for Evolution; they are the raw material of genetic variation.
Genetic Recombination:
This crossing-over process results in a recombination of parental genes. Subsequently, recombination by itself does not cause Evolution to occur. Instead, it is a contributing mechanism that works with natural selection by creating combinations of genes that nature selects.
Chromosomal Abnormalities:
Anomalies in the chromosome can be numerical or structural. A numerical exception occurs when one of the chromosomes in a pair is absent or when a person has more than two chromosomes instead of a pair.
Reproductive isolation:
Reproductive isolation mechanisms are a set of evolutionary mechanisms. They either prohibit members of different species from having children or ensure that all children born are sterile.
Natural Selection:
When any of those traits help some individuals survive and replicate rather than others, natural selection happens. This allows their genes to become more widespread in the population over time, and it's how animals adapt to environmental changes.