1. Energy Flow through a Food Chain

2. ENERGY FLOW Autotrophs vs. Heterotrophs

3. Energy Flow (Trophic Levels)
Producers- make their own food
Consumers- get energy from consuming producers

4. Producers
Producers- capture energy from sunlight or chemicals and use the energy to produce food.
Producers are autotrophs- they make food from their environment

5. 2 main types of autotrophs
Another type gets energy without light- by chemosynthesis
One type gets energy from the sun-by photosynthesis

6. Consumers
Consumers are heterotrophs- get energy from other organisms

7. Types of Consumers Herbivores- eat only plants Carnivores- eat animals
Omnivores- eat both plants and animals
Detritivores- eat dead matter (plants and animals)

8. Feeding Relationships
Energy flows through an ecosystem in one direction from:
1. the sun or inorganic compounds
2. To autotrophs (producers)
3. To heterotrophs (consumers)
Decomposers get energy from decomposing dead organisms

9. Food Chain- a series of steps in which organisms transfer energy by eating or being eaten.
Food Web- A network of feeding relationships.
(More realistic that a food chain)

10. Food Web

12. They can become very complex!

13. Trophic levels
Each step in a food chain or a food web is called a trophic level.
Producers are the first trophic level
Consumers are the second, third, or higher trophic level
Each trophic level depends on the one below for energy

14. Energy Pyramid
Only part of the energy stored in one level can be passed to the next- most energy is consumed for life processes (respiration, movement, etc., and heat is given off)
Only 10% of the energy available within one trophic level is transferred to organisms in the next trophic level

15. Biomass Pyramid
Biomass- the total amount of living tissue within a given trophic level.
A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.

17. Energy Losses Energy transfers are never 100 percent efficient
Some energy is lost at each step
Limits the number of trophic levels in an ecosystem
Energy flow is a one way path! (not a cycle)

18. All Heat in the End
At each trophic level, the bulk of the energy received from the previous level is used in metabolism
This energy is released as heat energy and lost to the ecosystem
Eventually, all energy is released as heat