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How does the body and its capacities change from conception through late adulthood?

Topic 3.2 Physical Development Across the Lifespan: describe prenatal development and teratogens, infant reflexes and motor milestones, the changes of puberty and adolescence, and the physical and sensory changes of adulthood and aging.

A focused answer to AP Psychology Topic 3.2, covering prenatal stages and teratogens, newborn reflexes and motor milestones, the physical changes of puberty and adolescence, and the physical and cognitive changes of adulthood including menopause and the distinction between fluid and crystallized abilities.

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  1. What this topic is asking
  2. Prenatal development
  3. Infancy and motor development
  4. Adolescence and puberty
  5. Adulthood and aging
  6. Try this

What this topic is asking

Topic 3.2 traces the body's development across the whole lifespan. The College Board wants you to know prenatal stages and teratogens, newborn reflexes and motor milestones, the physical changes of puberty and adolescence, and the physical and sensory changes of adulthood and aging.

Prenatal development

Prenatal alcohol exposure can produce fetal alcohol syndrome, with physical and cognitive deficits, illustrating why the embryonic stage is an especially sensitive window.

Infancy and motor development

Newborns are born with reflexes, automatic responses with survival value:

  • Rooting reflex: turning toward a cheek touch to find food.
  • Sucking reflex: sucking on objects placed in the mouth.
  • Grasping reflex: closing the hand around an object that touches the palm.
  • Moro (startle) reflex: flinging out the arms when startled.

Adolescence and puberty

Puberty is the period of sexual maturation that launches adolescence. It brings primary sex characteristics (the reproductive organs) and secondary sex characteristics (non-reproductive traits such as body hair and voice change). The growth spurt and hormonal changes of this period are a frequent exam scenario.

Adulthood and aging

Physical peak comes in early adulthood, followed by gradual decline. Menopause, the end of menstruation in midlife, ends reproductive capacity. Aging brings slower reaction time and processing speed, reduced sensory acuity (vision and hearing), and some memory change. Importantly, not all abilities decline: crystallized intelligence (accumulated knowledge and vocabulary) often holds steady or grows even as fluid intelligence (speed and novel reasoning) declines.

Reading physical development as one continuous arc helps you handle the scenarios the exam likes to pose. A prenatal exposure question is really about teratogens acting during a sensitive window; an infant question is usually about reflexes or the fixed maturational sequence of motor milestones; an adolescence question is about puberty and sex characteristics; and an aging question rewards the nuance that decline is selective, with crystallized abilities preserved. Holding the whole timeline lets you place any scenario in its stage and name the right mechanism rather than reaching for a vaguer answer.

Try this

Q1. Define a teratogen and give one example. [2 points]

  • Cue. A teratogen is an agent that crosses the placenta and harms prenatal development; alcohol (causing fetal alcohol syndrome) is one example.

Q2. Explain why motor milestones appear in the same order across children. [1 point]

  • Cue. They are driven by maturation, the orderly biological unfolding of the nervous system and muscles, so the sequence is universal even though timing varies.

Exam-style practice questions

Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

AP 2024 (style)1 marksMultiple choice. A pregnant person consumes alcohol, and the developing child is later born with facial abnormalities and cognitive deficits. The alcohol acted as which of the following? (A) A reflex (B) A teratogen (C) A maturational milestone (D) A primary sex characteristic (E) A critical period
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The answer is (B) A teratogen.

A teratogen is any agent (such as alcohol, certain drugs, or viruses) that can cross the placenta and harm prenatal development. Prenatal alcohol exposure can cause fetal alcohol syndrome, marked by facial abnormalities and cognitive deficits.

(A) a reflex is an automatic newborn response. (C) a maturational milestone is a typical developmental achievement. (D) primary sex characteristics are reproductive organs. (E) a critical period is a window of heightened sensitivity, not the agent itself; alcohol is the teratogen acting during such a window.

AP 2023 (style)4 marksConcept-application free-response question. A health educator is preparing a lifespan presentation. Explain how EACH of the following applies to physical development: a teratogen, the rooting reflex, puberty, and menopause.
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A 4-point concept-application FRQ; one point per term.

Teratogen (1): an agent such as alcohol or a virus that crosses the placenta during the prenatal period and can harm the developing fetus.
Rooting reflex (1): the newborn's automatic tendency to turn the head and open the mouth toward a touch on the cheek, helping the infant find the nipple to feed.
Puberty (1): the period of sexual maturation in adolescence, when reproductive capacity develops and secondary sex characteristics appear.
Menopause (1): the natural cessation of menstruation in midlife, ending a person's reproductive capacity.

Markers reward each term being correctly defined AND tied to a stage of physical development.

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