Food Chains

What is a Food Chain The sequence of what eats what in a biological community Usually starts with the sun Next link—an organism that uses the sun to make its own food –Plants –Chemosynthetic bacteria –Called AUTOtrophs or producers

What is a Food Chain Next link—organisms that eat the autotrophs –Called- Herbivores or primary consumers Deer that eats grass Next link—animals that eat the herbivores –Called Secondary consumers, predators, or carnivores

What is a Food Chain Next link—organisms that eat the secondary consumers –Called- Tertiary consumers or predators Next link—animals that eat the tertiary consumers –Called- Quaternary consumers or predators

Does it ever end? The last link in the chain is known as the top predator. –Has no known natural enemies Alligator Hawk Polar bear Can you think of one more?

What does it look like? Energy flows from one organism to the next with a loss at each level Trophic level in a chain –The position it holds in chain Producer, primary consumer, etc.

But its dead! Organisms that eat a dead organism are called detrivores or scavengers –Worms –Crabs –Vultures They are further broken down by decomposers –Bacteria –Fungi

Not set in stone A network of many food chains Organisms can function at different levels depending on diet Bear eats berries—primary consumer Bear eats deer—secondary consumer Bear eats salmon—Tertiary consumer –Where is your place in the food chain? List the things you had for dinner last night or breakfast this morning

Number of organisms Energy is lost from one organism to another –More plants (autotrophs) than plant eaters(heterotrophs) –More plant eaters (heterotrophs) than meat eaters(carnivores) Interdependence –When one species goes extinct it can affect an entire chain of other species

Equilibrium Fluctuating balance –Number of meat eaters (carnivores) ↑ then the number of plant eaters (herbivores) ↓, then the number of carnivores ↓ so the number of herbivores ↑