Scientific study recurrent psychological changes across the human lifespan, focusing on development from prenatal period to early, but sometimes middle and late adulthood. Reporting age child shows specific skills and understandings. The death of an individual creates the opportunity for new individuals to enter the world. When the genome of a being is complete (union of sperm and egg) Gamete: one of two sex cells, egg or sperm, that fuse together during fertilization. Trait that is designed and preserved by the process of natural selection. Developing child was designed by natural selection to solve age-specific problems. Child has a reproductive advantage in their current environment. Environment that provides the features that the genome needs or expects in order to develop typically. How info in the environ interact with the child to have lasting changes and how problems in the environ. Mind of a newborn is a blank slate.