The systematic approach to biology started with the Greek philosophers about 2,500 years ago. Aristotle (384-322 B.C.) is considered the "father of biology" for his classification of animals and for performing the first known biology experiments, dissecting plants and animals and studying the development of the chick in its egg. His student Theophrastus (ca. 372-286 B.C.) laid the foundation of botany, describing and classifying more than 500 plants and also describing the ways plants can germinate and grow. In Roman times, Lucretius (99-55 B.C.) proposed one of the earliest theories of evolution. But other than medical knowledge, biology made little progress until after the Middle Ages.
In the 15th and 16th centuries Europeans explored the Americas and some of the Pacific islands, and regular contact between Europe and southern Africa and eastern Asia was instituted. As a result European scholars were exposed to a great variety of plants and animals that were new to them. They responded with books describing and classifying both newfound and familiar plants and animals, starting as early as 1530. A few years later the first botanical gardens began to be established. When the scientific revolution of the 17th century began, scientists undertook more detailed experiments in biology. For example, Jan van Helmont (1579-1694) carefully measured the weight of soil in a tub as a willow grew there, establishing that the increase in mass of the willow was much greater than any diminution of mass of the soil.