‘A plant is an animal standing on its head’

Abstract

The view that plant materials derive from the earth and are absorbed as food through the roots (which was widely held by scientists until the beginning of the 19th century) is described. School students today hold at least superficially similar intuitive views, which impinge on their learning about photosynthesis. Examples of ways in which an examination of the earth-and-roots historical model can be used to give credence to students' prior knowledge and to promote discussion about that knowledge, are described.

Keywords:

• Photosynthesis
• Constructivism
• History of biology