1. March 17, 2016 Bell Work: What is primary succession? Objective:
The student will be able to…
Describe the flow of energy through ecosystems.

2. Today in History
1941 The National Gallery of Art opened in Washington, D.C.
1942 Gen. Douglas MacArthur arrived in Australia to become supreme commander of Allied forces in the southwest Pacific theater during World War II.

4. Movement of Energy Through Ecosystems
Anything an organism does in an ecosystem requires energy
The flow of energy controls what type of organisms that live in an ecosystem
It also controls how many organisms an ecosystem can support.

5. Primary Energy Source
The sun is the ultimate source of energy for all living organisms
All organisms depend on the energy the sun emits in one way or another

6. Primary Energy Source
Primary productivity is the rate at which organic material is produced by photosynthetic organisms
Primary productivity manages the amount of energy available in an ecosystem

7. Primary Energy Source
Producers are organisms that first capture the energy and make energy-storing molecules.
Includes plants, some bacteria, and algae
Consumers are the organisms that consume plants and other organisms to obtain the necessary energy to build their molecules.

8. Quick Review
What is the primary source of energy for all living systems?
What does the amount of energy produced in an ecosystem depend on?
Explain the difference between producers and consumers.

9. Trophic Levels
Trophic Level: one of the steps in a food chain or food pyramid; examples include producers, and primary, secondary, and tertiary consumers
Energy moves from one trophic level to another

10. Trophic Levels

11. Trophic Levels
A food chain is the path of energy through a trophic level in an ecosystem
Producers are the first level of a food chain.
Use energy from the sun to produce their food
Many also absorb key substances from the environment, such as nitrogen, and build them into their molecules

12. Trophic Levels
The second level of the food chain consists of primary consumers
Consumers must consume plants or other organisms to obtain energy
Primary consumers are herbivores
Herbivores are animals that eat plants and other producers
Must be able to break down plants’ molecules into usable compounds

13. Trophic Levels
The third level of the food chain consists of secondary consumers
Carnivores are animals that eat other animals
Example: Wolves, tigers, snakes, most felines
Omnivores are animals that eat plants and other animals
Example: Bears, humans,
Both carnivores and omnivores are secondary consumers
Secondary consumers cannot digest cellulose

14. Trophic Level
Detritivores are organisms that obtain their energy from the organic wastes and dead bodies produced at all trophic levels
Bacteria and fungi are known as decomposers
Decomposers cause decay
Decomposition releases nutrients back into the environment
Tertiary consumers make up a fourth trophic level in many ecosystems
This level is composed of carnivores that eat other carnivores
Also called top carnivores

16. Trophic Levels
A food web is a complicated interconnected group of food chains
In most ecosystems, energy does not flow in straight path. Organisms feed at several trophic levels.

18. Energy in Food Chains
Potential energy is the energy stored in chemical bonds of leaves.
This energy is transferred through the food chain
During the transfer of energy in an ecosystem, energy is lost through heat
The amount of useful energy available decreases as the energy passes through the ecosystem
This limits the number of trophic levels and ecosystem can support

19. Energy in Food Chains
Photosynthesis only captures about 1% of energy available to leaves
10% of energy is transferred to each trophic level
Herbivores only get 10% of the potential energy from plants and other organisms. 90% is lost to heat.
Carnivores only get 10% of the potential energy from other animals they consumes. 90% is lost as heat.
At each trophic level, one tenth (1/10) of the energy is stored than that stored by organisms in the previous trophic level.

20. Energy in Food Chains
The flow of energy through an ecosystem can be illustrated with an energy pyramid
Energy pyramid: a diagram in which each trophic level is represented by a block and the blocks are stacked on top of each other with the lowest trophic level being on the bottom.
The width of each block is determined by the amount of energy stored in the organism at that trophic level.

22. Energy in Food Chains
Most terrestrial ecosystems involve only three or four trophic levels
Four or more trophic levels is very rare
Too much energy is lost at each level for an ecosystem to support more than three or four trophic levels
The number of individuals may not be an accurate indicator of the amount of energy of that level
Depends on the size of the organisms
Larger animals use more energy

23. Energy in Food Chains
Biomass is the dry weigh of tissue and other organic matter found in an ecosystem.
Each level of an energy pyramid contains only 10% of biomass found in the trophic level below it.

25. Vocabulary

26. Ticket Out
What is a trophic level?