Aristotle's biology was a natural science that studied the structure, function, growth, origin, evolution and distribution of all living things. He believed that all living things share a common essence and that the differences between them are due to their environment. Aristotle's views on biology were based on observations and logical reasoning rather than experimentation. He divided living things into two categories: plants and animals. He studied the anatomy of plants and animals, their reproductive systems, and their behavior. He also studied the development of embryos and proposed theories about heredity. Aristotle's writings on biology were influential for centuries and laid the foundation for modern biological studies.