1. Chapter 10 Ecosystems p

2. What is an ecosystem?
A community of living organisms interacting with one another and with non-living parts of the environment they live in
Individual population community ecosystem
Examples: forest, lake, island, mountain

3. Trophic relationships
Feeding connections among living organisms in an ecosystem
Can be represented by a food chain (p.319)
3 trophic levels:
Producers
Consumers
Decomposers

4. Producers Primarily plants in terrestrial ecosystems
Primarily algae and phytoplankton in aquatic ecosystems
Autotrophic (self feeding) organisms convert inorganic (non-living) to organic (living) matter
For example, plants convert carbon dioxide to glucose with help of solar energy
Autotrophs are at bottom of food chain, they introduce energy to an ecosystem
Photosynthesis is key!

5. Consumers
Heterotrophic (need others for nourishment) organisms that feed on other living organisms
4 types:
Primary (1st order), feed on producers, seeds, fruit (herbivores)
2nd, 3rd, 4th order consumers, eat consumers of preceding order (usually carnivores, can also be omnivores)

6. Decomposers
Organisms that feed on waste and remains of other living organisms (detritus)
Called detritivores, feed on dead leaves, wood, animal remains, excrement, etc.
Examples are worms, fungi, bacteria, some insects

7. Trophic networks More than one food chain is possible in an ecosystem
This means there are many trophic relationships
A trophic network illustrates all of them

8. What we’ve learned so far:
Everything in an ecosystem is connected
Food chains link organisms in an ecosystem
funny food chains

9. Material flow and chemical recycling
Matter an energy are constantly exchanged between organisms
Law of conservation of mass: matter cannot be created or destroyed, only transformed
Chemical recycling is when decomposers break down organic matter into inorganic matter
This allows an endless cycle of exchange in an ecosystem

10. Flow of inorganic matter Flow of organic matter
Decomposers
Detritus
Consumers
Producers
Environment
Flow of inorganic matter
Flow of organic matter

11. ENERGY = Energy Flow Sunlight is the primary source of energy
It is transformed into chemical energy by plants then passed on to consumers
From one trophic level to another energy is lost (waste, movement, growth, reproduction, heat)
So UNLIKE matter, energy is not recyled, we need a constant supply from the sun (p.325)
ENERGY =

12. Primary productivity in ecosystems
The amount of new biomass generated by producers
Biomass is the total mass of organic matter in an ecosystem
Primary productivity is important because it tells us how much energy is available to primary consumers and therefore limits the # of organisms that can live in an ecosystem
Influenced by:
Sunlight (needed for photosynthesis)
Water (needed for photosyntesis)
Nutrients (C, N, P, K)
Temperature

13. Disturbances Events that damage an ecosystem
Can lead to elimination of organisms or can alter the availability of resources
2 types:
Natural (environmental), such as storms, flooding, forest fires, volcanic eruptions, drought, etc.
Human (caused by people), such as litter, logging, oil spills, etc.

14. Ecological succession
Series of changes that occur in ecosystems after a disturbance.
Continue until a balance is restored
One small change can alter an entire ecosystem