1. Food Webs and Pyramids

2. Feeding Interactions Terms
Autotroph(Producers) - Plants, produce energy from the sun. How?
Heterotroph(Consumers) - obtain energy from consuming (eating)
Herbivores - consumers that only eat plants
Predators - eat other animals
Carnivores - meat only
Omnivores - meat and plants
Decomposers – organisms that obtain energy from dead organic material, return organic material to the abiotic ecosystem
Bacteria
Fungi, slime molds
Photosynthesis

3. Food Chain
Shows energy movement through a single feeding interaction in an Ecosystem.
Arrows represent energy movement
Grass Grasshopper Frog Snake Red tailed Hawk
Primary Consumer
Top-level Consumer
Producer
Secondary Consumer
Tertiary Consumer
Herbivore
Predator
Predator
Predator

4. Food Web Shows all the feeding relationships in an community.
Arrows show the movement of energy

5. Trophic Levels Trophic levels in a food chain
Grass Grasshopper Frog Snake Red tailed Hawk
Primary Consumer
Top-level Consumer
Producer
Secondary Consumer
Tertiary Consumer
Trophic levels in a food chain
Producer, Primary Consumer, Secondary Consumer, Tertiary Consumer, Top-level Consumer
-or-
Producer, 1st level consumer, 2nd level consumer, 3rd level consumer, top-level consumer

6. Trophic Levels – Food Web
Organisms can play multiple roles in an ecosystem
Ex. The Bat is both a primary consumer and a secondary consumer

7. What is Biomass?
Total dry mass of all the living material in an ecosystem.
Used to quantify the biotic components of an ecosystem

8. Ecological Pyramids
Diagrams that display a feeding relationship in an ecosystem and another aspect of that feeding relationship, such as…
Energy at each trophic level
Biomass at each trophic level
Population at each trophic level

9. Energy Pyramid
Diagram showing a feeding relationship and the total energy at each trophic level.
Energy measured in kJ, J, or cal.
10% rule – approximately 10% of energy contained in a trophic level is available to the next trophic level (90% is “used”)

10. Biomass Pyramid
Shows the consumable Biomass for each trophic level.

11. Pyramid of numbers
Shows the population of each trophic level

12. Lab 2-3: Owl Pellets
Calculate a pyramid of numbers and biomass pyramid for the barred owl based on observations from its pellets

13. Owl-Pellet Pyramid of Numbers Consumption for 1 owl for 1 year
Predator
Top-level consumer
1 Owl
Prey
Herbivores (mostly)
Primary Consumers
Prey (mice, shrew, moles, birds)
#? Producers (Plants)

14. Owl-Pellet Biomass Pyramid Consumption for 1 owl for 1 year
Top-level Consumer
.8 Kg Owl
Primary Consumers
80 kg Mice, Shrews, Moles, Birds
Producers
3,648 kg Plants, seeds, nuts, grains…