Extract: Well over 90% of our existence as a species was prior to the development of agriculture, which has brought forth many cultural changes. Thus understanding our biology and our capacity to respond to the environment may be enhanced by reference to our own evolutionary history. Moreover, knowledge from our recent past (i.e., the study of life history), particularly the environmental conditions experienced by our parents and grandparents and from our own early life, provide additional insights. These elements come together - our combined ecological, evolutionary, and societal histories -- in understanding the concept known as "developmental origins of adult disease," first described over a decade ago. One genotype (a specific genetic make up) can generate a range of phenotypes (features or characteristics). Much of this diversity is determined by developmental plasticity, processes by which environmental influences induce irreversible changes in the developmental path of the organism. Developmental plasticity must be distinguished from developmental disruption in which an environmental challenge is teratogenic (causes defects in the fetus) and disruptive to the normal pattern of development.