1. Nutrition & Energy Flow
Chapter 2, Section 2

2. How are these items related to one another in an ecosystem?

3. How Organisms Obtain Energy
The Sun is the ultimate source of energy for life.

4. Producers Photosynthetic Autotrophs Use light energy to make glucose
Sun flower, grass, algae bloom – Qingdao, China (hosted Olympic sailing)

5. Consumers Heterotrophs Herbivores = feed only on plants
Carnivores = eat other heterotrophs
Scavengers = eat dead animals
Omnivores = eat both animal and plant materials
Decomposers = break down and release nutrient from dead organisms
Vulture: Scavenger; African WildDog: Carnivore (most efficient carnivore – kill 90% of prey they go after – work in groups); Zebra: Herbivore; Chimpanzee: Omnivore (Eat fruits and meat); South Arican Mushroom: Decomposer

6. Flow of Matter and Energy in Ecosystems
Models to show how energy moves in one direction through an ecosystem
Food Chains
Food Webs
Ecological Pyramids
Arrows indicate the direction of Energy Flow

7. Ex: berries  mice  black bear
Food Chain
Arrows show transfer of energy
Ex: berries  mice  black bear
A portion of energy is given off as heat at each transfer
Amount of energy in final transfer is only a fraction of what was at the first transfer
Does all the energy from every plant on the planet get used by the herbivores?

8. Trophic Levels = Each organism represents a feeding step in the movement of energy
Note: Book calls them 1st, 2nd, 3rd order heterotrophs

9. Food Web
Shows all possible feeding relationships at each trophic level in a community

10. Ecological Pyramids Base always represents 1st trophic level
Higher trophic levels are layered on top of one another

11. Pyramid of Energy = Energy decreases with each trophic level moving up
Total energy transfer from one trophic level to the next is only about 10% (90% is lost)

12. Pyramid of Biomass = Less living material as you move up trophic levels

13. Cycles in Nature
Matter moves through the trophic levels of an ecosystem.
Energy can be lost through heat; Matter is not gained or lost, it is recycled.
Ex: Water Cycle, Carbon Cycle, Nitrogen Cycle, Phosphorous Cycle

14. Water Cycle Water present 3 billion years ago is still present today
It’s been recycled between land, ocean and atmosphere
Evaporation (water gas)
Condensation (clouds)
Precipitation (rain)

16. The Carbon Cycle Putting Carbon in the Ground:
Plants use CO2 to create carbon compounds (sugar) for growth and energy
Consumers eat plants and/or other animals to get carbon compounds for growth and energy
Plants and animals die, carbon is returned to the ground where fossil fuels can form
Putting Carbon in the Atmosphere:
CO2 gets released during cell respiration
CO2 released when burning fossil fuels

18. The Nitrogen Cycle
See figure 2.19 on page 56

19. The Phosphorous Cycle
See figure 2.20 on page 57

20. Practice
Why is a pyramid a good shape to represent how matter and energy transfer in an ecosystem? Why not use a circle or a square?

21. According to the Law of Conservation, matter can neither be created nor destroyed. Make a relationship between this statement and the recycling of carbon in an ecosystem. (Hint: All life on this planet is carbon based. What happens to a tree that dies & falls in a forest? Who benefits from the dead tree?)