Evolution is a blind causal process in which genes or blueprints for certain traits can either aid or hinder an organism in its present environment, either allowing the organism to survive and reproduce or to die. These traits are then passed on to the next generation. A gene is said to be successful if it codes for a trait that enables an organism to survive and reproduce. Sexual reproduction is more advantageous than asexual reproduction, in that it provides more variation. An individual is created by the genes of two parents and so may be more successful.
Cloning is successful only if the parent was well adapted to the present environment.
For example, in the EEA, sugar was needed for survival. Organisms that carried a gene for liking of sugar survived. The proximal cause for sugar preference is that it tastes good. An Evolutionary Stable Strategy is a srategy which, if most members of a population adopt it, it cannot be bettered by an alternative strategy. I am not very sure on this concept but will try to give an example.