Introduction

Introduction to Growth

Growth is when a living thing becomes bigger and more complex as it gets older.

This means the body parts of the plant or animal add more weight and change form as they grow up.

Growth happens because the tiny units that make up the body, called cells, are dividing to make more cells.

It is important to know that you cannot reverse growth.

Growth is an irreversible process.

This means that once a child grows into a tall person, they cannot shrink back to be a small baby again.

Growth shows in many ways in the body:

Increase in volume

Increase in size

Increase in the number of body parts

Increase in length

Increase in weight

Growth is a natural process that does not happen instantly; it takes time.

It is a process where the body builds new things.

Growth is an anabolic process.

This means the body takes simple things and joins them together to make bigger, complex things.

For any living thing to grow, the cells must have plenty of food.

This food gives the body energy and the materials needed to make new protoplasm, which is the living material inside every cell.

Growth in Unicellular Organisms

Tiny living things that have only one cell, like Amoeba, grow until they reach their biggest possible size.

When they get to that maximum size, they stop growing and start making babies to create new individuals.

This reproduction usually happens by a simple method where the one adult cell just splits into two new daughter cells.

Growth in Multicellular Organisms

All big living things with many cells, like humans or trees, start their life as just one single cell that has been fertilized.

This first single cell starts to divide, first splitting into two cells, then those two split into four, and it keeps going like that.

This process of cells dividing over and over is how the whole organism grows bigger and bigger.