Food Chains and Food Webs
What's for dinner?"
Food Chains
 A food chain is the sequence of who eats
what in a ecosystem.
Food Chains
 A food chain starts with an energy source.

The sun

Deep sea vents
 In our woods, what was the primary energy
source?
• CD
Food Chains
 The 1rst link in the chain is an organism
that makes its own food from the energy
source.

Usually photosynthesis
 These are called Primary Producers

Or Autotrophs.
Food Chains
 In our woods, what are the Autotrophs?
• CD
 How ‘bout the pond, what are the Primary
Producers?
• CD
Food Chains
 Next come organisms called primary
consumers.

These are the organisms that eat the
autotrophs.
 Organisms that eat plants are called
herbivores.

An example is a bunny that eats grass
Food Chains
 Next link in the chain are the animals that
eat herbivores.
 These are called secondary consumers.

an example is a snake that eat bunnies.
Food Chains
 These animals (the secondary consumers)
are eaten by larger predators called tertiary
consumers.

For example, owls eat snakes...
Check out these food chains.
Food Chains
 Primary producers are autotrophs.
 Primary consumers are herbivores (plant-eaters).

Eat secondary consumers.
 Secondary consumers are carnivores (meat-eaters) or
omnivores (animals that eat both animals and plants).

Eat secondary consumers.
 Tertiary consumers are carnivores or omnivores

Eat secondary consumers.
 Quaternary consumers are carnivores or omnivores

Eat tertiary consumers.
Food Chains
 The arrows in a food chain show the flow of
energy, from the source to a top predator.
As the energy flows from organism to
organism, energy is lost at each step.
Food Chains
 A network of many food chains is called a
food web.
More Players in a Food Web
 When any organism dies,

It is eaten by detrivores
• (worms, maggots,crabs)

It is broken down by decomposers
• (bacteria, fungi)
Food Webs
Food Webs
Food Webs
Food Webs