1. Energy Flow and Matter Cycles!

2. Trophic Structure
37.9 – 37.14

3. What you need to know!
How energy flows through the ecosystem by understanding the vocabulary that relate to food chains and food webs.
Explain primary productivity graphs.

4. Trophic Levels Structural levels that help organize ecosystems
Food chains are the simplest trophic system
Producers (autotrophs) always form the bottom level
Primary consumers (herbivores) always form the second level
Secondary consumers, tertiary consumers, and quaternary consumers (omnivores and carnivores) make up all the top most levels
Decomposers (Detritivores) are a trophic level that consume waste and dead organisms
They are traditionally excluded from graphic representations
A food web is a more accurate, dynamic representation of the feeding relationships within a community

5. Primary Productivity
The amount of sun energy converted into chemical energy for use by life in an ecosystem
This can be measured in mass or energy
The mass of all the life in an ecosystem is the biomass
The primary productivity is the energy available to the rest of the organisms in an ecosystem
The more energy available, the more life the ecosystem can support

6. Energy Budget
Only 10% of the energy from one trophic level makes it to the next level
Most of the energy is used by the organism and lost as heat (entropy)
Energy flows up trophic levels and is ultimately lost (it does not cycle like nutrients)

7. Biogeochemical Cycles
Chapter – 37.20

8. What you need to know!
The water, carbon, nitrogen, and phosphorus chemical cycles
The various abiotic reservoirs for each cycle

9. Nutrients Recycle
Biogeochemical cycles are the interactions between biotic and abiotic factors that account for the recycling of nutrients in an ecosystem
All four major cycles share a pattern:
Nutrients are stored in an
abiotic reservoir
Nutrients move through the
food web
Detritivores decompose
everything back to the
reservoir

10. The Water Cycle

11. Water Cycle
Evaporation & transpiration (from plants) accounts for all the water in the atmosphere.
Water forms clouds (condensation), and then rains (precipitation) back down to the Earth.
Water runs into streams and rivers (runoff) or is absorbed into the ground (seepage) to become ground water.
Water is taken up by the roots of plants or it makes its way to the oceans, flowing above ground or below ground.
Abiotic Reservoir = Oceans, Lakes, & atmosphere

12. The Carbon Cycle

13. Carbon Cycle
Photosynthesis, cellular respiration, and decomposition take up and release Carbon and Oxygen.
Volcanic eruptions and erosion release Carbon Dioxide into the atmosphere and oceans
Burial and decomposition of dead organisms store Carbon underground (coal & oil).
Human activities, such as cutting and burning forests, and burning fossil fuels, release Carbon Dioxide into the atmosphere.
Climate change (global warming)
Abiotic Reservoir = atmosphere & fossil fuels

14. The Nitrogen Cycle

15. Nitrogen Cycle
Nitrogen Fixation changes the nitrogen in the air into nitrogen that plants can use in the soil (nitrate ions & ammonium ions).
Lightning, bacteria, fertilizer
Once Nitrogen has been fixed in the soil it is then taken up by the roots of plants (producers).
Abiotic Reservoir = atmosphere

16. The Phosphorus Cycle

17. Phosphorus Cycle
It is not abundant in the atmosphere, so it follows a simple cycle.
soil  producer  herbivore  carnivore  decomposer  back to soil
Abiotic reservoir = rocks

18. Human Disturbance
Human alteration of habitats can impact multiple ecosystems
Example:
When forests are cut down there are fewer plants to absorb essential nutrients in the soil
Water washes the nutrients away to other ecosystems
These other
ecosystems are also
altered