1. Aim What factors contribute to the stability of an ecosystem?

2. Biodiversity Biodiversity- means many different types of organisms
Every population is linked, directly or indirectly, with all of the other populations in an ecosystem. Maintaining diversity is essential to maintaining equilibrium. In other words organisms are interdependent. They rely on each other. What ecosystem would be more stable, the desert or the tropical rain forest? Explain

3. Interdependence
The removal of one organisms from the food web could lead to instability
What would happen if the zebra were removed because of disease? Hint –All three organisms affected are in this picture

4. Example of interdependence
What will be directly affected if I remove the rabbit population from this food Web? In other words , what populations would increase and which ones would decrease? Explain

5. Need more producers than consumers
Producers convert energy from the sun into food to provide energy for all other living things.
What would happen if an ecosystem contained more consumers than producers?

6. Decomposers Bacteria and fungi
Dead organisms and wastes must be recycled so that raw materials can be made available to be reused by plants.
What would happen if their were no decomposers to recycle dead material?
Bacteria and fungi

7. Ecosystem Stability Summary
What are two main conditions necessary for a stable ecosystem to exist?

8. Recycling of carbon and oxygen
The atmosphere acts as a reservoir for carbon dioxide (CO2), oxygen (O2) and water (H2O). These are inorganic molecules.
These inorganic compounds can be exchanged directly from organisms through the processes of photosynthesis and respiration.
Write the two equations for photosynthesis and respiration. How do they compare?

9. Some Processes By Which Nutrients Are Recycled
Cycling within an ecosystem involves a number of processes.
These are best considered by focusing attention on specific nutrients such as oxygen, water and carbon dioxide.

10. CARBON, HYDROGEN AND OXYGEN CYCLES IN ECOSYSTEMS
C, H & O basic elements of life; making up from about 98% of plant biomass.
CO2 and O2 enter the ecosystem from the atmosphere.
Producers convert CO2 and H2O into organic compounds (glucose) and release O2 (Oxygen). This process is photosynthesis
Producers, consumers and decomposers convert glucose (organic), using O2, back into CO2 and H2O (inorganic). This process is respiration

11. Name the two life processes that are responsible for recycling carbon and oxygen? Explain how these two processes accomplish this.

12. What is a characteristic of a stable environment?
1.It usually contains only one type of producer.
2.It usually contains a great diversity of species.
3.It contains simple food chains that have more consumers than producers.
4.It contains complex food webs that have more heterotrophs than autotrophs.

13. Decomposition and decay of organic matter are accomplished by the action of
1.green plants
2.bacteria and fungi
3.viruses and algae
4.scavengers

14. Which statement best describes a characteristic of an ecosystem?
1.It must have producers and consumers but not decomposers.
2.It is stable because it has consumers to recycle energy.
3.It always has two or more different autotrophs filling the same niche.
4.It must have organisms that carry out autotrophic nutrition.

15. If the population of mice is reduced by disease, which change will most likely occur in the food web?
The cricket population will increase.
The snake population will increase.
The grasses will decrease.
The deer population will decrease

16. A stable pond ecosystem would not contain
1.materials being cycled
2.oxygen
3.decomposers
4.more consumers than producers