Year 1 · Plants and animals · Section 1.2

Growth and development

Growth

Growth is the process in which organisms, such as plants and animals, become larger and gain mass. A bean seed provides an example. Its seed coat protects the seed. Water can enter through a small opening, the micropyle, which is important for germination.

During germination, the embryo grows into a seedling. The cotyledons contain stored food and supply nutrients until the young plant can make enough food by photosynthesis.

A seed

Many plants grow from seeds, such as bean seeds. A seed has a seed coat, a hilum marking where it was attached to the parent plant, and a micropyle through which water can enter.

The embryo inside the seed is the beginning of a new plant. During germination, the seed coat splits and the seedling uses food stored in the cotyledons to grow.

Life cycle

A life cycle is a repeating sequence from seed to plant and back to seed. A tomato seed germinates and grows into a plant, which produces flowers and eventually fruits containing seeds. These seeds can grow into new plants, starting the cycle again.

Development

Development involves changes in an organism's structure and functions. New parts appear or existing parts become able to perform new tasks. For example, a tomato plant develops branching roots that can take up water effectively.

Animals

Animals also grow and develop. A penguin chick already has many body structures when it hatches, but it continues to grow, gain mass and develop into an adult.