1. Energy Flow in Ecosystems (cont.)
Producers are photosynthetic organisms (like plants) that produce carbohydrates (sugar).
Consumers get their energy by feeding on producers or other consumers.
Decomposers break-down wastes & dead organisms, through the process of biodegradation.
Includes fungi, bacteria, some insects & worms

2. Methods to represent energy moving through ecosystems.
1. Food chains: show the flow of energy in an ecosystem.
Each step is a trophic (or feeding) level
Producers = 1st trophic level
Primary consumers = 2nd trophic level
Secondary consumers = 3rd trophic level
Tertiary consumers = 4th trophic level

4. This dung beetle is a detrivore.
Consumers in a food chain can be classified as:
Detrivores (decomposers) - obtain energy & nutrients from dead organisms & waste matter.
they feed on every trophic level.
Herbivores = primary consumers
eat plants (producers) only
Carnivores (or Omnivores) = secondary, tertiary, or quaternary consumers
This dung beetle is a detrivore.

5. Secondary consumers eat primary producers
Eg. Frog eating a grasshopper
Tertiary consumers eat secondary
consumers
also called top predators, top
carnivores or top consumers
Eg. Lions eating gazelle
NOTE: Omnivores = consumers that eat both plants & animals
Eg. include humans and bears

6. Most organisms are part of many food chains.
2. Food webs
represent interconnected food chains.
model the feeding relationships in an ecosystem
Arrows in a food web represent the flow of energy & nutrients.
Arrows go UP to the top carnivore(s).
This food web represents a terrestrial ecosystem that could be found in British Columbia.

7. 3. Food pyramids (a.k.a. ecological pyramids):
show the changes in available energy, biomass, or population size from one trophic level to another

8. The amount of life an ecosystem can contain is based on the bottom level of the pyramid.
Only about 10% of energy is leftover and transferred to next level