3.2 Physical Development Across

Teratogens

agents, such as chemicals and viruses, that can reach the embryo or fetus during prenatal development and cause harm

Maternal Illness

Syphilis, mumps, genital herpes, severe influenza

Genetic Mutation

a change of the sequence of a DNA molecule

Developmental Norms

The average age at which individuals display various behaviors and abilities.

Rooting reflex

a baby's tendency, when touched on the cheek, to turn toward the touch, open the mouth, and search for the nipple

visual cliff

a lab device for testing depth perception in infants and young animals

Critical period

an optimal period shortly after birth when an organism's exposure to certain stimuli or experiences produces proper development

Imprinting

the process by which certain animals form attachments during a critical period very early in life

Primary sex characteristics

the body structures (ovaries, testes, and external genitalia) that make sexual reproduction possible

Secondary sex characteristics

nonreproductive sexual characteristics, such as female breasts and hips, male voice quality, and body hair

Menarche

the first menstrual period

Spermarche

first ejaculation

Menopause

the time of natural cessation of menstruation; also refers to the biological changes a woman experiences as her ability to reproduce declines