Evolution and the regulation of growth and body size

Abstract

The relationship between body size, organ size, and life history parameters has long been recognized. Correlates between body size and clutch size, life span, gestation time, and maturation time have been well studied in myriad taxa. Similarly, changes in morphology are associated with major life history transitions. The decision to grow horns in a beetle, become a worker or a queen ant, or develop a defensive helmet in Daphnia all involve changes in organ growth, and have important life history implications. Consequently, the genetic, developmental, and physiological mechanisms that regulate body and organ growth are intimately involved with those which regulate life history. Further, evolutionary changes in the mechanisms that regulate body and organ growth will coincidently impact other life history traits, and vice versa. This chapter discusses the mechanisms that regulate growth and body size in animals and how they evolve. It also explores how these mechanisms regulate other life history parameters, and how this may influence the evolution of both morphology and life history.