DVP - The Lifespan and Physical Development in Childhood Lesson

Learning Targets:

• Explain the process of conception and gestation, including factors that influence successful prenatal development.
• Discuss the interaction of nature and nurture (including cultural variations), specifically physical development, in the determination of behavior. 
• Discuss maturation of motor skills. 

AP psychology course and exam description, effective fall 2020. (n.d.). https://apcentral.collegeboard.org/media/pdf/ap-psychology-course-and-exam-description.pdf

Prenatal Development

Prenatal development begins at conception and occurs in three distinct phases. Conception is the release of the mother's egg and fertilization by one of two hundred million sperm released by the father. Once sperm has penetrated an egg you have a zygote (the single cell formed at conception from the union of the egg cell and the sperm cell). Once the zygote is formed you enter the germinal period of development. This phase lasts approximately two weeks. When the zygote is formed it is no larger than a period at the end of a sentence in a textbook. As a zygote, your cells (a combination of chromosomes from mom and dad) begin to divide rapidly, and your heart begins to beat. During this rapid cell division, some of the structures that house and protect the developing fetus will form and they will eventually become implanted in the mother's uterine wall. Less than half of all zygotes survive these first two weeks. If the zygote does survive over a period of nine months, the single cell will develop into a newborn baby.

The embryonic period is crucial to development and begins around three weeks and lasts until about eight weeks. The brain is the first major organ to form. The central nervous system begins to form, as well as the nervous system, legs, arms, eyes, ears, and teeth. During this stage, you begin to look human. Genes on your sex chromosomes will trigger the development of your sex organs. Toward the end of this period, your bones begin to form.

The last and longest phase of development is called the fetal stage and lasts from around nine to thirty-seven plus weeks. The main task during this time is to prepare for life outside of the womb. Your organs continue to grow, the fetus continues to increase in size, reflexes begin in preparation for life outside the womb, and you begin to put on fat. During the final two months, a fetus will double in size with an extra three pounds of fat to prepare for temperature regulation outside of the womb.

During fetal development, the fetus is housed in an amniotic sac and is connected to the mother through the umbilical cord. The umbilical cord acts as a lifeline or filter. Through it the fetus receives nourishment and oxygen, and it is necessary to remove waste.

Teratogens

During prenatal development, there are many things that can go wrong. While the placenta and umbilical cord act as a filter to the developing fetus, sometimes harmful agents the mother either ingests or is exposed to travel through the placenta and affect the child in a harmful way. These chemical agents that can harm the prenatal environment are called teratogens, they can cause abnormal development or even birth defects. The earlier the exposure to the teratogen, the more severe the effects.

One common example is alcohol. Alcohol use during pregnancy can lead to what is called FAS or Fetal Alcohol Syndrome. It is the number one cause of intellectual disability and is present in 1% of all births.

The Newborn

Newly born infants come armed with a collection of physical and sensory capabilities. These capabilities are mostly for survival. Examples include a preference for sweet foods, attraction to human-like faces and human voices over other sensory stimuli, and reflexes.

Complete the newborn reflexes activity below.

Maturation

Maturation is the natural and biological process of changing over time in an individual, independent of any specific environment or social influences. As a result of natural aging, it describes the progression of physical, cognitive, and emotional abilities. Many developmental milestones are influenced by maturity, including motor skills, language acquisition, social development, and abstract thinking. Maturation suggests that, regardless of external factors, individuals undergo inherent and predictable changes throughout their lives.

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