Periods of development in the life span is usually divided into broad age ranges: the prenatal period (the period from conception to birth), infancy and toddlerhood (birth to age 3), the preschool period (ages 3 to 6), middle childhood (ages 6 to 12), adolescence (ages 12 to 20), young adulthood (ages 20 to 40), middle adulthood (ages 40 to 65), and late adulthood (age 65 to death).
Generally, we think there are 3 Periods of development such as infancy, childhood and teenagers in early period of development. But developmentalists focused on early age development and break this part into these five periods of development:
- Prenatal Development (conception through birth)
- Infancy and toddlerhood (birth through two years)
- Early childhood (3 to 5 years)
- Middle childhood (6 to 11 years)
- Adolescence (12 years to adulthood)
- 1 1.Prenatal Development
- 2 2. Infancy and Toddlerhood
- 3 3. Early Childhood
- 4 4. Middle childhood
- 5 5. Adolescence
Lets go through the prenatal development that is conception through birth. With conception the prenatal development begins to unfold.
In the germinal stage, the first—and shortest—stage of the prenatal period, the zygote begins to divide and grow in complexity during the first two weeks following conception.
By the end of the germinal period— just two weeks after conception—the organism is firmly secured to the wall of the mother’s uterus. At this point, the child is called an embryo. The embryonic stage is the period from two to eight weeks following fertilization.
The final period of prenatal development, the fetal stage, that the developing child becomes easily recognizable. The fetal stage starts at about eight weeks after conception and continues until birth. The fetal stage formally starts when the differentiation of the major organs has occurred.
Understanding nutrition, teratogens (or environmental factors that can lead to birth defects), and labor and delivery are primary concerns prenatal development.
2. Infancy and Toddlerhood
Infants grow at a rapid pace over the first two years of their lives. In the first days of life, infants’ body rhythms— waking, eating, sleeping, and eliminating—govern the infant’s behavior, often at seemingly random times. These most basic activities are controlled by a variety of bodily systems. One of the most important ways that behavior becomes integrated is through the development of various rhythms, which are repetitive, cyclical patterns of behavior.
There are also gender and ethnic differences in weight and length. Girls generally are slightly shorter and weigh slightly less than boys differences remain throughout childhood. The disparities become considerably greater during adolescence. Furthermore, Asian infants tend to be slightly smaller than North American Caucasian infants, and African American infants tend to be slightly bigger than North American Caucasian infants.
During the first two years of life, the rest of the body begins to catch up. By the age of two, the baby’s head is only one-fifth of body length, and by adulthood it is only one eighth. With a very keen sense of hearing but poor sense of vision, a newborn is transformed into a walking, talking toddler within a short period of time.
3. Early Childhood
Early childhood, also known as the preschool period, which extends from the end of infancy, at about the age of two, to around age six, is an exciting time in children’s lives. The preschool years mark a time of preparation: a period spent anticipating and getting ready for the start of a child’s formal education, through which society will begin the process of passing on its intellectual tools to a new generation.
Changes in Body Shape and Structure.
If we compare the bodies of a two year-old and a six-year-old, we find that the bodies vary not only in height and weight, but also in shape.by the time children reach six years of age, their proportions are quite similar to those of adults. Other physical changes are occurring internally. Muscle size increases, and children grow stronger. Bones become sturdier. The sense organs continue to develop.
Nutrition: Eating The Right Foods.
Preschoolers need less food to maintain their growth. The change in food consumption may be so noticeable that parents sometimes worry that their preschooler is not eating enough.
Health and Illness
The average preschooler has 7 to 10 colds and other minor respiratory illnesses in each of the years from age 3 to 5.
When children of different ages gather at a playground, it’s easy to see that preschool children have come a long way in their motor development since infancy. Both their gross and fine motor skills have become increasingly fine-tuned.
4. Middle childhood
Physical Development: slow but steady these three words characterize the nature of growth during middle childhood.
During middle childhood, children master many types of skills that earlier they could not perform well. For instance, most school-age children can readily learn to ride a bike, ice skate, swim, and skip rope.
Physical and Mental Health during Middle Childhood:
For most children, this is a period of robust health, and most of the ailments they do contract tend to be mild and brief. Routine immunizations during childhood have produced a considerably lower incidence of the life-threatening illnesses that 50 years ago claimed the lives of a significant number of children. Illness is not uncommon, however. For instance, more than 90 percent of children are likely to have at least one serious medical condition over the six-year period of middle childhood, according to the results of one large survey. And although most children have short-term illnesses, about one in nine has a chronic, persistent condition, such as repeated migraine headaches.
Information Processing In Middle Childhood.
It is a significant achievement for first graders to learn basic math tasks, such as addition and subtraction of single-digit numbers, as well as the spelling of simple words such as dog and run. But by the time they reach the sixth grade, children are able to work with fractions and decimals. According to information processing approaches, children become increasingly sophisticated in their handling of information.
Lev Vygotsky proposed that cognitive advances occur through exposure to information within a child’s zone of proximal development, or ZPD. The ZPD is the level at which a child can almost, but not quite, understand or perform a task.
Regardless of the nature of the ceremonies celebrated by various cultures, their underlying purpose tends to be similar from one culture to the next: symbolically celebrating the onset of the physical changes that turn a child’s body into an adult body capable of reproduction. With these changes the child exits childhood and arrives at the doorstep of adulthood.
Growth during Adolescence.
Adolescence is the developmental stage that lies between childhood and adulthood. It is generally viewed as starting just before the teenage years and ending just after them. Adolescents are considered no longer children, but not yet adults. It is a time of considerable physical and psychological growth and change. In fact, in only a few months, adolescents can grow several inches and require a virtually new wardrobe as they are transformed, at least in physical appearance, from children to young adults. Boys’ and girls’ adolescent growth spurts begin at different times. girls begin their spurts around age 10, while boys start at about age 12. During the two-year period starting at age 11, girls tend to be taller than boys. But by the age of 13, boys, on average, are taller than girls—a state of affairs that persists for the remainder of their life span.
The period during which the sexual organs mature, begins when the pituitary gland in the brain signals other glands in children’s bodies to begin producing the sex hormones, androgens (male hormones) or estrogens (female hormones), at adult levels.
Puberty in Girls
It is not clear why puberty begins at a particular time. menarche, the onset of menstruation and probably the most obvious signal of puberty in girls, varies greatly in different parts of the world.
Puberty in Boys
Boys’ sexual maturation follows a somewhat different course. The penis and scrotum begin to grow at an accelerated rate around the age of 12, and they reach adult size about three or four years later.
Also read about development issues in humans, click here.
Berk, L. E. (2006). Child Development. (7 Ed). New Delhi: Pearson Education Dorling Kindersley India pvt ltd.