ABSTRACT
In Chapter 1, we presented a compilation of the many types of chemical compounds that plants produce. Now the question arises: How do plants synthesize these compounds, and why do plants synthesize such a vast array of compounds? These are the primary topics of this chapter, and in the process of exploring the answers, we hope to shed some light on the factors that drive the evolution of the biosynthetic pathways that produce these compounds. For example, the simple fact that plants have roots results in very different selective pressures than those driving the evolution of animal metabolism. After all, very few plants have the ability to run away when another organism sees them as food. Consequently, plants have evolved ways to repel or, in some cases, attract other organisms. Their lack of movement also allows them to produce rigid compounds (such as cellulose or lignin) that, among other things, allow them to grow upward into new environmental niches.
