Human Life Cycle


Human beings are culture species that fall under the genus Homo and the family Hominidae. In appearance, human beings are physically similar to apes. Earlier, only human beings were the species exclusive to the family Hominidae. But a recent study suggests that chimpanzees are more closely related to humans than gorillas and the last mutual ancestor between humans and chimpanzees, lived about 6 to 7 million years ago.

A human body consists of four limbs; which are two arms and legs, and a head and neck attached to the torso. The shape of the human body is formed from a strong skeleton which is made of bone and cartilage, covered with fat, muscle, organs, tissue and so on.

A huge difference between apes and humans is that humans have a more developed or evolved brain. The body structure of human beings is erect and showcases movable hands. Apes also show great cognitive talent which was earlier unknown to humans.

The human body undergoes numerous changes and developments since conception. The food humans eat, helps them to develop. If we look at this historical trail of human evolution, there are many highlights to be looked upon. But for now, let’s look at the life cycle of a human being to get a better understanding.

Life Cycle of Human

The following are the different stages of development in the human life cycle

1) Foetus:

The sperm from the adult male human and the egg from the adult female human form a zygote inside the uterus of the female. Over time, the zygote develops and forms an embryo. Initially, the embryo looks like a cluster of cells, but after eight weeks, the embryo resembles the human body and is called a foetus. During this stage, the foetus is entirely dependent on the female for breathing, eating and other kinds of resources.

2) Infancy:

After around nine months, the foetus is fully developed to be born. This stage in human development marks the period from birth to age one. Infancy is the earliest part of childhood, where the infant grows in size and shape. During this stage, infant requires a lot of attention as they are completely dependent on their mothers. Infants develop their behaviour, physiology and cognition. Gradually, the infants learn to suck, swallow and cry if they are in an uncomfortable situation. Since infants are unable to speak, crying is their way of communicating. The mother tends to breastfeed her infant during this stage.

3) Toddler years:

The term ‘to toddle’ means to walk unsteadily and the child has a clumsy walk during this period. This stage marks the end of early childhood. During this period, the child ages two to three years old. This stage in a child’s life is where they undergo immense cognitive, emotional and social development.

4) Childhood:

Here, a child is of age three to six years and is crawling for mobility. In this stage, the child crawls and eventually learns to walk, talk, eat independently, and become more aware of their surroundings. The child is more social and active during this period and intrigued to learn new things.

5) Adolescence:

Here, the child is of age from nine to thirteen years and this period marks the beginning of adolescence. In this stage, the child grows into an adolescent, through a period called puberty. Puberty occurs during the initial stages of their teenage years, and that’s why adolescents are also called teenagers. In this stage, the teenager grows rapidly and physical changes begin to appear. These changes include hair growth, structural changes in body shape, voice cracking in adolescent males, breast growth in adolescent females and so on.

The behaviour pattern also changes, as they are more independent in performing daily tasks.

6) Adulthood:

Human beings who are between the age of 20 to 60 years are known as adults. Here, human beings are sexually mature and capable of reproducing. The body is fully developed by now, and the adult gains experience and responsibility. Adults have full mental and social development by this stage.

7) Middle age:

This is the time period of adulthood between the age of 30 to 50 years.

8) Old age:

When an individual reaches 60 or 65 years of age, they are called old people. This period starts from 65 years of age, until the end of their lives. During this stage, the intestine absorbs fewer nutrients from food sources. The physical capabilities of doing tasks are also reduced and they again depend on external support to do things.

The behaviour of old people in this stage varies, depending on the immunity and lifestyle of the human. The average life expectancy of human beings varies from 70 to 85 years. But this also changes depending on their lifestyle.


A human being’s body undergoes several changes and developments throughout their life span and food acts as the fuel needed for all these changes. Proper nutrition, exercise and a friendly environment ensure a healthy human beings in all stages of their life. Some basic nutrients required for human growth are carbohydrates, essential amino acids, fatty acids, vitamins and minerals in order to sustain a healthy lifestyle.

Frequently Asked Questions on Life Cycle of Human


What are the six stages of the human life cycle?

The six stages of human development include the foetus, infancy, toddler years, childhood, puberty, adolescence, adulthood, middle age and senior years.


What are the characteristics of human development?

The growth of different characteristics that occur is body structure, aptitude, intelligence, height, weight, hair colour, and sexual orientation.


What are the main objectives of human development?

The main objectives of human development include health, education, physical development and freedom. The objectives should also include human rights and social, economical and political freedom.

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