1. Chapter 3
Principles of Ecology

2. Ecosystems Nature in Balance

3. A. Organisms and their Environments
I. Ecology 3.1
A. Organisms and their Environments
Ecology-scientific study of interactions between organisms and their environment
Biosphere- Portion of earth that supports life
Biotic factors- All living things
Abiotic factors - Non-living parts of the ecosystem (air, temp, light, soil, water, etc.)

4. Non living Materials in an Ecosystem

5. Population- group of organisms belonging to the same species
Organism- a living thing (from one cell to multicellular)
Population- group of organisms belonging to the same species
Communities-collection of interacting populations
Ecosystem- interactions among populations in a community and the community’s physical surroundings (abiotic factors)

6. Communities and Interdependence

7. Niche- role a species plays (includes the space, food and, other conditions needed to survive and reproduce)
Habitat- place where an organism lives out its life

8. Ecology Movie 12 min.

9. B. Species Relationships
1. Feeding Relationships
Autotrophs- produce own food (plants, some bacteria)
Heterotrophs- depend on autotrophs to make their food for them

10. Herbivore – feed on grass and other plants
Carnivores- kill and eat live animals
Omnivores- feed on both plants and animals
Detritivores-feed on dead organisms (buzzard,
vultures, Scavengers )
Decomposers-break down dead or decaying organisms into basic compounds

11. 2. Symbiotic Relationships
Predator-Prey - benefits the predator harmful to prey
Commensalism - one benefits the other is neither helped nor harmed
Mutualism - both benefit
Parasitism- (parasite-host) the parasite benefits the host is harmed but, not quickly killed

12. Energy flow
What’s a food web?
What’s a Food Chain?

13. Trophic levels

14. C. Matter and Energy Flow
1. Food Chain - Simple model that scientists use to show how matter and energy move through an ecosystem
Trophic level - a feeding step in a food chain or web (producer, primary consumer, secondary consumer…)

15. Think of organisms that would be in a food chain and web

16. 2. Food web – expresses all the possible feeding relationships at each trophic level

17. 3. Pyramid of energy – the amount of energy available decreases at each trophic level.
Only about 10% is available for the next level to use, the other 90% is used by the organism for heat, movement, and reproduction…
4. Pyramid of numbers – Population size normally decreases at each higher trophic level.

18. Water Cycle

19. D. Geochemical Cycles
1. Water Cycle
Evaporation – water rises as vapor
Condensation – formation of clouds
Precipitation – Water (rain, snow, or hail) falling from the sky
Infiltration – (Seepage) water soaking into the ground
Runoff – water flowing above the ground to lakes or the ocean

22. 2. Carbon Cycle
The Carbon dioxide that is found in the air is taken into plants by the process of photosynthesis and stored as glucose for the plant to use for energy when it needs it.
Animals consume (eat) the plants and use the glucose for energy and breaths out CO2 during respiration.
Decomposers release carbon stored in dead organisms
Humans release carbon when we burn (combustion) organic materials (wood and paper) or fossil fuels (Coal, oil, and gas)

25. Carbon occurs in all living things and forms nearly 10 million known compounds. Carbon is the major chemical constituent of most organic matter, from fossil fuels to the complex molecules (DNA and RNA) that control genetic reproduction in living organisms.
Carbon is stored on Earth in a number of major reservoirs:
Carbon dioxide (CO2) in the atmosphere
Carbon dioxide dissolved in water
Carbonate (CaCO3) rocks (limestones and corals)
Fossil fuels - deposits of coal, petroleum, and natural gas derived from once-living things
Living plants
Dead organic matter - e.g. harvested wood and wood products, plant litter, humus in the soil
Carbon is continuously cycled between these reservoirs in the ocean, on the land, and in the atmosphere. This carbon cycle has been continuing naturally since plant life took hold on land about 400 million years ago.
Quantities are expressed in billion tonnes of carbon.

26. 3. Nitrogen Cycle
Nitrogen makes up 78% of the atmosphere
Nitrogen-fixing Bacteria can make nitrogen into usable form for other organisms
Legumes contain nitrogen-fixing bacteria in their roots nitrogen is added to the soil (ex. clover, soybeans, peas)
Consumption of plants high in nitrogen enables us to make proteins for our bodies.
Excretion of excess nitrogen in the urine or animal waste returns nitrogen to the soil for plant use.
Decomposers release nitrogen stored by plants and animals