what was the impact it had?
It inspired some of Darwin's most ardent supporters—and provoked the strongest opposition.
Natural selection
 This inspired some of Darwin's most ardent supporters—and provoked the strongest opposition. 
where does all the natural variation necessary for natural selection come from This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. what is this all about? Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. were there any theories based on it? Yes, Darwin's theory. how is it classified? It can be classified in several different ways, such as by its effect on a trait, on genetic diversity, by the life cycle stage where it acts, by the unit of selection, or by the resource being competed for. what can you tell me about its name? The term "natural selection" is most often defined to operate on heritable traits, because these directly participate in evolution. how is it associated with fitness? The concept of fitness is central to natural selection. In broad terms, individuals that are more "fit" have better potential for survival.
wiki:25631458
Natural selection [SEP] Impact
Darwin's ideas, along with those of Adam Smith and Karl Marx, had a profound influence on 19th century thought, including his radical claim that "elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner" evolved from the simplest forms of life by a few simple principles. This inspired some of Darwin's most ardent supporters—and provoked the strongest opposition. Natural selection had the power, according to Stephen Jay Gould, to "dethrone some of the deepest and most traditional comforts of Western thought", such as the belief that humans have a special place in the world.