Human Development


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In today’s Basic Science class, We will be discussing Human Development. We hope you enjoy the class!


human-growth-basic science classnotesng


Have you noticed that a baby does not remain the same size after birth and that the baby grows and develops? One of the changes that are easily noticeable in a healthy baby some weeks or months after birth is an increase in size, height and weight. The food the baby eats is important in helping the body to produce new body cells that will add to the body size.

Development is a series of orderly changes by which a living thing comes into maturity. These changes are cumulative and eventually add up to important and significant differences in humans.

Developmental changes are different from an increase in size (growth) and they move from simple to complex.

Developmental changes can be broadly divided into:


This is the stage from birth till puberty and it is characterized by light bodyweight, relatively small size, muscular motions, sitting, crawling, walking, talking, very rapid growth particularly in the first two years of life and growing of teeth.

Baby growth process. From newborn to preschool child



This is the stage before adulthood. At this stage, puberty occurs. Puberty is a transition stage and it is the period when the body of a school-age child turns into that of a matured adolescent. Some of the observable features in this stage are common to both boys and girls even though they also have their own distinct features.

adolesence human development basic science classnotesng

In boys, the following changes occur:

  1. Development of facial hairs, moustache, pubic hair and armpit hair
  2. Deep voice or broken voice
  3. Developed reproductive organ with evidence of the production of the male reproductive cell (sperm)
  4. Growth in muscles and penis.

In girls, the following changes occur:

  1. Rounder face and buttocks
  2. Enlargement of hips
  3. Production of the female reproductive cell (egg) as evidence in the commencement of menstruation
  4. Growth in breast, uterus and pelvis.




This is the stage of full maturity and it is characterized by an increase in weight and size, the appearance of grey hair, gradual decline in body functions including the decline in reproductive activity and weakness of organs.


Growth and developmental changes can either be temporary or permanent. Permanent changes remain for life and are not reversible.

The features associated with the human developmental stages are irreversible and hence, permanent. Temporary changes are reversible and can be corrected once discovered.

Permanent changes include:

  1. Increase in size, weight and height
  2. Walking, talking and growing of teeth in children
  3. Pubertal development

Temporary changes include:

  1. Growth of pimples on adolescent and young adult’s face
  2. The fatness during childhood commonly called baby fat
  3. Malnutrition or kwashiorkor

Temporary changes may naturally disappear after some time. They can also be corrected medically or by a change in behaviour whereas permanent changes remain with the individual throughout life.



We have come to the end of this class. We do hope you enjoyed the class?

Should you have any further question, feel free to ask in the comment section below and trust us to respond as soon as possible.

In our next class, we will be talking about Earth in Space. We are very much eager to meet you there.

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