1. Ecosystems Part 2
Trophic Levels

2. Food Chains
The biotic interaction of predation creates food chains within an ecosystem.
In a food chain, each organism depends on the previous organism as a source of food.

3. Food Chains
Food chains show the path of energy from one living thing to another.
The arrows point in the direction of energy flow.

5. Food Webs
Interlocking food chains.

6. deer
snake
wolf
mouse
grass
rabbit
frog
shrubs
hawk
insect

7. Trophic Levels A hierarchy in a food chain.
Each level is defined by how much energy the organism gains.

8. Trophic Levels Producers
Make own food by photosynthesis, uses energy from sunlight
Plants
Also called Autotrophs

9. Trophic Levels Consumers Eat producers or eat other consumers
Also called heterotrophs
Primary
Secondary
Tertiary

10. Consumers Herbivore Omnivores Carnivores Eats only plants
Eat plants and animals
Examples: humans, brown bears
Carnivores
Eat only animals
Examples: lions

11. Consumers Scavengers Decomposer Eat dead things, do not kill prey
Examples: vultures, raccoons
Decomposer
Consume dead material and return nutrients to the soil
Examples: worms, bacteria, fungi

12. Trophic Levels Classify each organism: crow coyote grass maple tree
bacteria
snake
mouse
deer
red squirrel
seeds

13. Energy Transfer
The sun is the primary source of energy in a food chain.
Food energy ingested by a consumer is used for life processes.
Only 10% of energy is transferred from one level to the next.

14. Energy Transfer
Why do we rarely see more than 4 links in a food chain?
Because energy decreases along the chain so higher level consumers cannot be supported.