WHAT IS THE HUMAN LIFE CYCLE? - BIOLOGY - 2025

The human life cycle can be explained as the time that elapses from fertilization and birth to death. Absolutely all living organisms have a life cycle, that is, a period of time that elapses between the beginning and the end of life.

During that time they carry out different functions such as feeding and reproducing. Both plants and animals go through three stages in their life cycle.

They start as a fertilized seed or ovule, grow into an immature individual, and finally become adults that can reproduce, giving rise to the next generation.

The life cycle can be made up of more than three primordial stages depending on the species. The study on the cycle of life and ages, comes from remote times, as well as the awareness that human beings have of knowing that if they were born, they will die.

As human development is a process of permanent changes that occurs throughout life, each stage is very important because what happens in each one benefits or harms the next stage.

Stages that comprise the human life cycle

The stages that comprise the human life cycle are those that human beings go through during their life until they reach adulthood. In this cycle, both biological and environmental forces act, which go through different stages from the prenatal phase to old age and death.

Each stage involves changes in the body and therefore, each stage is unique. Those stages in the human being are basically five:

1 - Prenatal period

It occurs from the moment of conception to birth. When the baby is ready to come out, the mother's body pushes it through the vagina for delivery. This stage comprises three periods:

Germinal

It begins with conception, when the sperm fertilizes the ovum and the egg or zygote is formed, which begins to divide to form the embryo that implants in the uterus.

Embryonic

It is the first trimester of pregnancy and the stage in which the embryo is in full development.

It is the most sensitive period to possible damages by diverse factors.

Fetal

At this stage the embryo reaches its perfection, the fetus already has the shape of a human being and will continue to mature for 7 more months until birth.

2 - Childhood

At birth, the baby is called an infant. This is a period of amazing change; goes from birth to early adolescence. Childhood has several stages:

Neonatal

It includes the first month of life. It is a vitally important stage.

Postneonatal or lactating

It includes the first year of life and in it there are great changes in psychomotor development.

Early childhood

It occurs until the age of 3, when it begins to perfect the language. In this phase, they learn to control their bowels and show a strong desire to explore and discover things.

Preschool period

From 3 to 6 years, this is the stage of childhood in which the ability to relate to others is gained.

They can take on complex tasks and accommodate their own behavior with gender roles.

3 - Adolescence

At this time, you stop being a child without reaching the maturity and poise of a person in adulthood.

There are different criteria to determine when one stage of adolescence ends and another begins. However, that does not mean that there is not a certain acceptance about these phases:

Pre-adolescence

It goes from 8 to 11 years old, a stage in which it passes from childhood to adolescence. In most cases it coincides with the beginning of puberty.

The physical changes in this stage are considerable, affecting many parts of the body, making it difficult to coordinate movements.

Early adolescence

Between 11 and 15 years, the main hormonal changes occur. After this phase, the body is quite different from that of pre-adolescence and the opinion of others tends to be highly valued.

Late adolescence

Last stage of adolescence, occurs around 15 and 19 years.

During this phase the corresponding stature is reached and the complexion of the body becomes entirely adult. Social conscience is fully developed.

4 - Adulthood

It is the stage of life development in which fullness is achieved in biological, physical and psychic evolution.

At this stage, personality and character stabilize. The mature individual is recognized by the control he achieves over his emotional life and his feelings.

The stages of adulthood are:

Early adulthood

It is the beginning of adulthood, roughly from 25 to 40 years old.

Middle adulthood

Stage between 40 and 65 years, in which greater stability is expected. Although it is still a time of great productivity and experience, it slows down, leading to the cessation of productive life and old age.

5 - Old age

Aging is a phenomenon present throughout the life cycle from the moment of conception until death. Despite being something natural, it is difficult to accept it as an innate reality.

It is a stage in which it is necessary to give great importance to health care. Aging is characterized by the decline in metabolic and other functions of the body.

Sensory sensitivity, elasticity and muscle tone, agility and reaction capacity are lost. There is deterioration of bone structures, decreased collagen in the skin and protein absorption, appearance of wrinkles, and progressive loss of libido.

It is a time of adaptations, especially to changes in physical capacities and personal and social situations.

This would be an ideal life cycle, with a normal aging phase, but the final stage of death can occur at any point in the cycle. Death is the end of life, it is the end of the living organism that had been created from birth.

References

1. Growing in Motion. (May 27, 2012). Obtained from Childhood and Its Stages: lainfancia.tumblr.com
2. Daza, KD (2011). Old age and aging. Research paper # 12, 6 - 11.
3. Dusheck, J. (2017). Reference. Obtained from Life Cycle, Human: biologyreference.com
4. Icarito. (June 2012). Obtained from Natural Sciences, Organisms, environment and their interactions: icarito.cl
5. Nappi, L. (2017). com. Obtained from What is a Life Cycle? - Definition, Stages & Examples: study.com