Key Terms
Development
Physiological, cognitive, behavioral, and social changes across the lifespan guided by nature and nurture.
Conception
Sperm fertilizes egg in the fallopian tube. Up to 500 million sperm compete; one penetrates, egg immediately blocks the
Zygote
Fertilized ovum formed when egg and sperm unite.
Embryo
Zygote after implantation in the uterine wall (through week 8).
Fetus
Developing organism from week 9 to birth; defining feature is growth.
Teratogens
Harmful substances that can bypass the placental filter and damage the fetus.
Risk increases with
Larger amounts, longer exposure, and more sensitive developmental phases (especially early pregnancy, often before the m
Cigarette smoking
Reduces blood oxygen for both mother and child; can cause severe underweight at birth.
Fetal Alcohol Syndrome (FAS)
Condition from maternal alcohol use causing developmental abnormalities; 1 in 500 U.S. births.
Poverty and homelessness
Substantially increase fetal risk by raising exposure to teratogens, malnutrition, stress, domestic violence, and substa
Rooting
Cheek is stroked; baby turns toward it and tries to suck. Ensures feeding.
Withdrawal
Pinprick to sole of foot; baby flexes leg. Avoids pain.
Tonic neck
Laid on back; turns head and extends arm on same side. Builds hand-eye coordination.
Newborns also have preferences
Sweet tastes at first; open to salty by 4 months. By 6 days old, prefers mother's smell over another mother's.
Habituation
Decreased response to a repeated stimulus; used to study infant cognition.