MutationMutations are sudden random

Mutation
Mutations are sudden random changes in the genetic material of a cell that may cause it to differ in appearance and behaviour from the norm.
Mutations happen for several reasons. One possibility is when DNA fails to copy accurately. External influences such as radioactivity, X-rays or chemicals can also create mutations by causing DNA to break down.
Mutations are entirely random and do not happen because they benefit or hinder the ability for an organism to adapt to its environment. It is Rare for these mutations to benefit the organism and when they do happen, they are known as adaptations.
Mutations can case evolution by substituting one allele for another in a in a gene pool. For example, a mutation in flower colour can cause an individual plant carrying the recessive phenotype, for example white flowers, to produce the gamete for the dominant allele, A, for red flowers. This would decrease the frequency of the a allele in the population while increasing that of the A allele.
On its own , mutation plays only a minor role role in evolution, having little offect on the numbers in a single generation because a mutation at a given gene locus is rare. Instead , they cause the gene pool to be affected over generations as individuals carrying the mutant allele produce a disproportionate number of offspring due to natural selection or genetic drift.
Having said that, mutation is still crucial to evolution as is the only one of the five factors where new alleles are being introduced into the gene pool. Hence, mutations are the raw material for evolution as they are the original source of genetic variation itself.