PLANTS AND ANIMALS – GROWTH AND REPRODUCTION

 

 

As plants and animals develop, they grow and get larger and heavier. How does this growth take place? We know that living things take substances, like food, into their bodies. Some of these substances become part of body cells. Cells get bigger until they cannot grow anymore and they divide into two. As more cells are formed, a living thing grows.

 

When living things are fully developed they are able to ‘reproduce’ and create new members of their species. Most living things in the animal world reproduce when special ‘sex cells’ from the mother and father join together. As this cell grows and divides, a new living thing develops.

 

 

 

 

This cell is ready to divide. The threads inside its nucleus, called “chromosomes”, have been duplicated. The nucleus now starts to divide and each new nucleus gets a complete set of chromosomes. The cell membrane then divides to form two separate cells. These are identical to the original cell with the same number of chromosomes. They will grow and eventually divide themselves into two new cells.

 

 

 

 

 

 

 

This calf will grow and develop for up to seven years before it becomes fully-grown.

 

 

 

 

 

 

 

Yew trees take 1,000 years to mature, while pine trees only take 30 years.