The History of Animals

Biology was a natural pursuit for Aristotle, given his family's medical background. In the zoological sciences, some of his observations were confirmed to be accurate only in the 19th century. On his work in The History of Animals, Aristotle draws the most important distinctions between animals with and without blood. Animals that reproducing offspring within the female's body, as generally the case with mammals and reproducing through the hatching of eggs. He shed some insights into the questions of reproduction and heredity. He also believed that no organ was given to an animal without a purpose. Final characteristics were those essential to an animal species, while variable characteristics consisted of qualities that develop rather than being naturally endowed.