The exact mechanisms behind natural evolution aren't known very well, but some of its aspects are. The living being can be 'built' by decoding its chromosomes. Evolution is a process that works on chromosomes instead of the living beings they represent. Natural selection is the relation between chromosomes and the performance of their decoded structures. The process of natural selection ensures that chromosomes that represent a good structure will more often reproduce than others.
Evolution occurs while reproducing.
Mutations can be the reason that chromosomes of children sometimes differ from the ones of their parents in certain places. The chromosomes of the parents are combined in a certain way to create new and different chromosomes for the children. Biologic evolution has no memory. All that it knows about individuals that perform well in their environment is stored in the set of chromosomes of the present individuals and in the way that chromosomes are encoded. He wrote algorithms that could reproduce chromosomes, represented as binary bitstrings, strings containing '1's and '0's.