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Natural Science - Year I

Unit 13: Biological Classification, Theophrastus, and Plants

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History Weblecture for Unit 13

This Unit's Homework Page History Lecture Science Lecture Lab Parents' Notes

History Lecture for Unit 13: Theophrastus and Botany

For Class
Historical Background: the beginning of botany

We have briefly mentioned the beginnings of medicine earlier in the course, when we discussed Egyptian science and the Greek "father of medicine", Hippocrates. One of the primary occupations of the medical doctor was the preparation of drugs from plants known to have medicinal properties--as cures for specific diseases, pain-relievers, or even prevention of different conditions. Those who used the different plants had no clear notion of how or why the plants were able to cause changes in the patient. Their evidence was largely empirical, based on close observation and experience of individual consumption and results, or what we might call anecdotal evidence. They did not have a way to present a theoretical explanation by extending generalized principles to all plants of a certain class.


The division in approach between empirical observations and deductions from theory is evident when the first systematic classification of plants, undertaken by Aristotle's student and colleague Theophrastus, is compared to the herbal of Dioscorides, a physician interested in collecting plants as cures. Not surprisingly, given their collaboration at the Lyceum, Theophrastus had much the same approach to plants as Aristotle did to animals.

Please read the paper Parts and Properties: A look at plant classification among the Greeks. This paper was written by a student at Tufts University

    As you read, consider the following points:
  • What characteristics does Theophrastus consider important in classifying plants? What classes does he finally determine for plants?
  • What characteristics does Dioscorides consider important in classifying plants? What classes does he finally use?
  • How does structure (roots, stems, leaves, seeds) contribute to classification?
  • Dioscorides thinks that it is important that plants with similar characteristics and medicinal properties be identified and classified together. Why?
  • What is the difference between a natural classification system and an artificial system?

Study/Discussion Questions:

Further Study/On Your Own