The purpose of this paper is to discuss each of the eight lifespan development periods (prenatal, infancy and toddlerhood, early childhood, middle childhood, adolescence, early adulthood, middle adulthood, and late adulthood) as cited by Laura E. Berk. The discussion reviews the basic facts, concepts, and developmental issues salient for each period.
This is the period during which a one-cell organism grows into a human baby. Eisenberg, Murkoff and Hathawy (1991) provide an extensive discussion of this period, pointing out that development proceeds according to genetic instruction. Gestation, the term commonly used to refer to all of the development occurring before birth, is said to occur in three stages: germinal, embryonic, and fetal.
According to the authors, it is during the germinal stage (fertilization to about two weeks) that the organism divides, grows more complex, and is implanted in the wall of the uterus. Cell division is rapid, moving from a single cell to a fluid-filled sphere (blastocyst) to an embryonic disk (a thickened cell mass) that will eventually develop into layers comprising discrete parts of the baby's physical body, e.g., the sensory organs, the digestive system, the skeletal-muscular system, and so forth. The blastocyst also develops into the nurturing and protective organs including the placenta, umbilical cord, and the amniotic sac.
The embryonic stage (2 to 8-10 weeks) is the period in which the major body systems (respiratory, alimentary, nervous systems) and organs develop. This is the critical stage in which birth defects are likely to appear and the vulnerability of the baby to environmental influences is maximal. A baby with multiple birth defects is likely to be spontaneously aborted during this developmental stage.
The fetal stage occurs from anywhere from 8 - 12 weeks after conception and continues to birth. It is marked by the appearance of bone cells and all of the "finishing touches...