Classwork Exercise and Series (Basic Science- JSS2): Changes In Living Things

Introduction

Growth can be defined as the quantitative increase in size, weight and height of a living thing. These changes which are observable and measurable accompany age increase. For growth to occur there has to be cell division and this division continues throughout the life of an organism and depends on nutrition and environment. Development deals with increase in the ability of the child to function properly in his environment. However, growth and development occur together in all aspects of life from birth till maturity.

Growth Changes

• Height: This refers to the increase in length of a living organism. it is measured in metres. Your ability to grow taller depends on such factors as the type of food you eat, environmental conditions, diseases and hereditary (characters inherited from parents by their children).
• Weight: Weight increases with growth, this makes an individual to become heavier as his age increases.
• Size: the height, the girth and the weight of an individual determine his size. Size therefore does not depend on the age of the individual alone but on the height, the weight and girth of the individual.

Developmental Changes

Developmental changes begin from conception of the child to adulthood. Physical developmental changes at:

Infancy (from 1-10 years)

• Rapid growth is noticed at very early stage.
• The child learns and starts walking, running and feeding himself at mid infancy.
• At the tail end of infancy, there is an increase in muscular co-ordination and the boys are usually taller and heavier than the girls.

Adolescence stage (11-16 years)

• This stage which marks the end of infancy usually experiences rapid physical growth in boys and girls and is often referred to as growth spurt.
• This growth spurt that occurs at each adolescent period is known as puberty.
• At the early stage of puberty, between the ages of 10 – 14 years, girls grow faster than boys, while from 15 – 20 years old the boys grow faster than the girls.

Adulthood (Above 20 years)

• Growth in height (length) ceases.
• The adult increases in weight and girth.
• The body skeleton becomes more rigid and firm.

Characteristic Features of Stages of Development

Infancy

1. Presence of hairs on the head.
2. Milk teeth predominant at this stage.
3. Bones are soft, hence the child’s inability to lift heavy loads.
4. The child is guided in most activities he/she engages in.

Adolescent stage

For the Boys:

1. Development of deep voice.
2. Broad shoulders are noticed.
3. Enlargement of the testes.
4. The legs and neck become muscular.
5. Hairs appear on the face, armpits, face and private parts.

For the Girls:

1. They experience menstruation.
2. They develop wide or broad hips and pelvic.
3. Development of enlarged breasts.
4. Appearance of hairs on the armpits and private parts.

Adulthood

1. Possession of permanent teeth.
2. Gradual setting of baldness or grey hairs.
3. Wrinkles appears later in life.
4. Weakness of bones and organs.
5. Decrease in physical growth and development.