Darwin argued that certain biologically inherited characteristics give an organism an advantage in surviving and reproducing compared to other organisms of the same species. The offspring would also inherit and pass on those advantages, and over generations the accumulation of these inherited advantages would lead to a new species.
Learning Goal 4
Darwin published his theory in the mid-1800s in Origin of Species. Its dramatic effect on biology can be traced to his use of clear and understandable argument, the inclusion of a massive array of evidence to support the argument, comparison of natural selection to the selective breeding of animals in wide use at the time, and the utility of the theory as a unifying framework for guiding future research.
Learning Goal 5
A mechanism that explained the origin of variation within species was suggested by several lines of evidence: findings from Gregor Mendel's experiments on the inheritance of traits in plants, the identification of genes and how they are sorted in reproduction, and the discovery of the mutability and near universality of the genetic code found in DNA.