population that reproduces at a high rate and lives in an unstable environment, natural selection could favor different phenotypic qualities at different times. This is also true on a larger scale. Microevolution is that which is inside a population, and macroevolution is the formation of new species and can be explained in terms of natural selection acting individuals within a population. Difficulties with the TheoryDarwin's Theory of Evolution had some difficulties, some unanswered questions. But, according to him, these "objections" were not strong enough pieces of evidence to nullify his theory. Darwin states that, "...the greater number are only apparent, and those that are real are not, I think, fatal to my theory." The first question is, "Why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms?" In other words, why do the individual species look so well-defined to us if they are in a state of change? Secondly, he says, is the question of the origin and transitions of organic beings with peculiar habits and structure. How could a terrestrial animal, for example, have been converted into a marine animal, because how could the transitional animal have lived? Another problem in his theory deals with instinct. Are instincts traits that can be modified or acquired through natural selection? Finally, why is it that crossing species produces sterile offspring, but crossing varieties produces fertile young? These four questions, and several others, are addressed in the book; Darwin wrote of these difficulties in order to protect himself from harsh criticism. He provides possible answers to these questions and in doing so covers most of the areas of doubt in the readers' minds.The Origin of Species provided the public with the first glimpse into the forces that drive evolution. Darwin provided explanations to previously unanswered questions ab...
