The main difference between plants and animals is how they obtain their food.

The only way an animal can obtain food is by eating something  that is (or used to be) alive.

A plant can make food using simple chemicals it can find in the soil or in the air..
Plants make food by a process called photosynthesis and this process cannot be carried out by any animal

The main parts of a flowering plant

flower2 FLOWER: Contains the reproductive organs. Where the plant makes seeds. Flowers that are insect pollinated (eg rose) have colourful or scented petals to attract insects. Wind pollinated plants (eg grass) do not have petals

STEM Transports food and water around the plant. Holds apart the leaves and flowers.

LEAVES Where photosynthesis is carried out. They have a large surface area to absorb as much sunlight as possible.

ROOTS: Soak up water and dissolved food from the ground.
They support the plant in the soil so it doesn’t blow over.
The root hairs increase the surface area of the root.


What do plants need to keep healthy?

Like us, plants are living organisms and grow best when their conditions are just right.

Plants need water, light, warmth, air and nutrients from the soil.
They also need space and time to grow.

Water:
Water is needed to transport food and chemicals around the plant.
It also helps keep the plant rigid.
With no water a plant will wilt (become floppy).
With too much water the leaves can go yellow.
Water is absorbed through the roots and moves around the plant be a process called transpiration.

Light:
Plants need light in order to make sugar by the process called photosynthesis.
The light energy normally comes from the Sun but can come from special bulbs.
When animals need energy they can eat sugar (or starchy foods).
Plants cannot do this so without light to carry out photosynthesis they will die.

Warmth:
Like us, plants grow better when it is warm.
You will notice that seeds start to grow in spring, when the weather gets warmer.
The grass in your lawn needs cutting  more in summer, when it is war,. than in winter.

Air:
We need air to provide us with oxygen gas.
Oxygen is needed to help release energy form sugar, during a process called respiration which happens all the time both in plants and in animals.
Seeds need oxygen from the air before they can germinate (start to grow in the soil).

Plants also need air to provide carbon dioxide gas which they need for photosynthesis.

Nutrients:
Plants cannot live just on sugar made by photosynthesis.
They also need nutrients from the soil which plants absorb through their roots, dissolved in water.

One of the important nutrients needed by plants is nitrogen.
Plants normally get their nitrogen from rotting vegetation (leaves, roots etc) found in the soil.

Space:
If plants get overcrowded they will be competing for water, light and nutrients.
Most will not grow well or die.
Only the taller, stronger plants will survive.
When plant produces seeds the plant has techniques for spreading its seeds around (eg a dandelion seeds get blown away) See seed dispersal

Time:
Seeds do not grow instantly.
Some seeds germinate quickly, eg some grass can germinate and be growing in a week.
Some seeds germinate slowly. A seed from a fir-cone may take two years before it starts to grow.