Ecology 6th Edition by Charles Krebs

Exercise 7

Alkaloids are plant defense chemicals, but not all plants contain alkaloids. Among annual plants, the incidence of alkaloids is nearly twice that among perennial plants. Tropical floras also contain a much higher fraction of species with alkaloids than temperate floras, and this is tine for both woody and nonwoody plants. Suggest why these patterns might exist, and how to test your ideas. Compare your ideas with those of Levin (1976).