Evolution is the change in a population's inherited characteristics, or traits, from generation to generation. The information used by the organism to produce these traits is stored on a complex molecule known as DNA. Smaller parts of this molecule that hold the information for one or more of its functions are known as genes. During reproduction, these genes are copied and passed on to the offspring. Random changes in these genes can produce new or altered traits, resulting in differences between organisms. Evolution then occurs when these modified genes become more common or rarer within a population. This happens through a mixture of the random changes of genetic drift and the more deterministic changes of natural selection, which are based on the reproductive value of the traits produced by the interaction of genes. Which process dominates depends on the effective population size, with smaller populations tending to be more influenced by the random variation of genetic drift, and the relative difference in reproductive success between competing genes, which determines how strongly natural selection acts on them. Genetics can even determine a species definition of and level of attractiveness.
Under natural selection, organisms with traits that help them to survive and reproduce tend to have more offspring. In doing so, they pass more copies of inheritable beneficial traits on to the next generation. This leads to advantageous traits becoming more common in each generation, while disadvantageous traits become rarer. As these small improvements accumulate over time, large changes can happen to the organism as a whole, adapting it more and more to its environment and ecological niche. The element of random chance in what mutations arise and which ones survive, as well as differences in environment, can cause different populations (or parts of populations) to begin to develop different strategies for survival, which can eventually cause the species to split, creating two species where one was before. All known species are descended from a single ancestor through this process of divergence.
The theory of evolution by natural selection was first put forth in detail in Charles Darwin's 1859 book on the Origin of Species(a book which caused enormous trouble and controversy). In the 1930s, Darwinian natural selection was combined with Mendelian inheritance to form the modern evolutionary synthesis. With its enormous explanatory and predictive power, this theory has become the central organizing principle of modern biology, providing a unifying explanation for the diversity of life on Earth.
Evolutionary biologists aim to discover the secrets behind the history and potential future of evolution, as well as the principles behind the process itself. A number of questions arise when considering the evolution of genetic patterns over time, especially with regard to what components of human behavior and psychology are strongly influenced by genetics. For instance, is it possible that evil is genetic? If so, what conditions support its proliferation through a population, and are other animals truly capable of it? Would it be possible to insert such potential "evil genes" into other life?
At first glance the question of evil as a successful evolutionary change within a population may seem to be an intriguing possibility, but its likelihood of success should be considered first. What reproductive advantage would such a characteristic provide to members of a population that would result in their offspring "out breeding" non-evil members. Wouldn't this particular evolutionary change counter act the very successful hominid tendency to sacrifice for the good of group members? Would such a mutation make an individual more likely to find mates (some carrying the same trait) or cause the existing hominid in-group altruistic behavior to attack the mutated individual as a threat to group members and thereby exclude it from society, and thus exclude it from the likelihood of reproducing?
Those with such a gene mutation would not even be able to form a successful population even if isolated from existing altruistic populations. Such a population would disintegrate from mutual repulsive reactions, thereby making mate finding less likely, due to its own tenancy to create lack of group cooperation. Homo Sapiens would quickly out compete this doomed population of Homo "Maleficum" for territory, just as we probably did to the Neanderthals.
No, evil, if such a subjective behavior can be objectively defined, is not a likely mutation to take hold in any population. Isn't "evil" merely the things that one does that really make some other very angry?
Richard Dawkins' "selfish gene" theory states that evolution should be viewed as genes using organisms to reproduce themselves. The fitness of an individual organism, or even an entire population, is secondary to the higher goal of proliferating the gene itself. It is unknown if these genes are possessed of a sentience in themselves, or if they merely mimic such behavior.