Aristotle's biology was a major contribution to the field of biology. He is credited with being the first to apply systematic observation and experimentation to the study of living things. He was also one of the first to recognize that living things could be classified into distinct groups, and he developed a system for classifying animals. Aristotle also made significant contributions to our understanding of anatomy, physiology, embryology, and behavior. He was particularly interested in the development of living organisms from their earliest stages, and his observations on this topic laid the foundation for modern evolutionary theory.