1. Roles in Ecosystems

2. Ecosystems include Abiotic (non-living) Components
e.g. physical (wind, sun temperature, altitude, etc.) & chemical (carbon, water, oxygen, etc.)
Biotic (living) Components
e.g. organisms

3. Biotic Components Producers make food from the abiotic environment
*all green plants are producers*
aka autotrophs (self feeders)
plants produce food through the process of photosynthesis
Photosynthesis
sun + carbon dioxide + water  food + oxygen

4. Biotic Components Consumers
cannot make their own food – they eat other organisms
aka heterotrophs (other feeders)
are ALL animals – they either depend directly or indirectly on producers for their food

5. Biotic Components Types of Consumers
Scavengers – eat larger dead organisms that they find (e.g. seagulls, vultures, hyenas, ravens)
Detritivores – eat smaller dead animals, feed on detritus (dead plant matter and animal dung) (e.g. earthworms, wood beetles, flies, crabs)

6. Biotic Components Types of Consumers
c. Decomposers – consume any remaining dead plant and animal matter, usually chemically breakdown the cells of an organism (e.g. fungi, bacteria)

7. Habitat – the place an organism lives Niche – an organism’s role in its environment

8. Trophic Levels Trophic levels are the feeding levels of consumers.
1st trophic level 2nd trophic level 3rd trophic level 4th trophic level
 producers  primary  secondary  tertiary quaternary
(autotrophs) consumer consumer consumer consumer
Niche producer herbivore carnivore top carnivore    
(plant eater) (animal eater)
Food grass  grasshopper  frog  hawk
Chain
A food chain shows the flow of energy from organism to organism.
Arrows in a food chains always POINT TO THE ORGANISM that is “doing the consuming”.

9. Food grass  grasshopper  frog  snake  hawk Chain Scavengers Detritivores Decomposers Breakdown dead organisms to recycle/release their nutrients back into the soil One more niche… omnivores – eat both plants and animals

10. Energy Flow Through a Food Chain
only 10% of energy is transferred to the next level in the food chain
energy is lost due to activity to stay alive, heat energy, waste
grass  grasshopper  frog  hawk
10000kJ 1000kJ 100kJ 10kJ
If grass has kJ of energy available, how much would be left for the hawk once it reached the top of the food chain?
What are the consequences for the hawk… the top carnivore?

11. Food Webs
Food webs shows all the different pathways that energy moves through a community of organisms. Food webs show that MANY organisms obtain energy from MANY DIFFERENT sources and provide energy to MANY DIFFERENT organisms.