Feeding

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					Feeding Relationships
• A food chain shows a simple feeding relationship.

Sun →
• All food chains start with the sun

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Feeding Relationships
• A food chain shows a simple feeding relationship.

Sun → grass →

Feeding Relationships
• A food chain shows a simple feeding relationship.

Sun → grass → rabbit →

Feeding Relationships
• A food chain shows a simple feeding relationship.

Sun → grass → rabbit → fox

All food chains start with ENERGY from the sun

carbon dioxide from the air

water from the roots

energy from sunlight (or light)

food transported to the rest of the plant

Photosynthesis
carbon dioxide from the air

water from the roots

energy from sunlight (or light)

food transported to the rest of the plant

Because plants produce their own food, they are called ‘Producers’

The energy is then passed on to animals when they eat the plant.

Animals of all shapes…

…and sizes!

Because these animals are the first to take the food energy from the plants,

They are called primary consumers

Some of these primary consumers have predators. Other animals that feed on them

Aphids are eaten by….

Ladybirds

Animals that eat primary consumers are called secondary consumers

• So far this is a straightforward food chain

• Sun → aphid → ladybird

But in reality it is more complicated than that

This bird eats ladybirds and aphids

This bird eats smaller birds, mice, and rabbits

Mice and rabbits have other predators

What will eat the frog?

What do you think the frog eats?

Sometimes it’s not entirely clear who eats who!

We can show what goes on with the help of a Food Web

What would happen if a disease killed off many of the hawks?

There will be nothing to eat the snakes, so their numbers will increase.

All the frogs get eaten

No frogs.

More crickets

Most of the cattail gets eaten by the crickets

Now the crickets don’t have enough food so their numbers go down

..and so on. Numbers of each species have an effect on the numbers of the other species in the web.

• Use the food web worksheet to predict what might happen in the following situations:
• A) There is very little rain and much of the Marsh Grass and Cattail die off.

• B) Humans nearby bring cats into the area.
• C) The frogs eats some poisoned slugs from a garden


				
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posted:6/2/2008
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John Nova John Nova
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