1. THE BIOSPHERE

2. The Biosphere – the portion of the earth where living organisms exist; extends from ocean floor into atmosphere
Ecology is the study of the interactions among organisms & between organisms and their environments
Biotic – Living
Abiotic – non living factors, determine
what types of organisms can
survive
Organisms and their environment are interdependent

3. Levels of Organization – Fig. 3-2
Species – group of similar organisms that can breed and produce fertile offspring
Population – all individuals of a species within a certain area
Community – all populations within a given area
Ecosystem – community plus abiotic factors
Biome – group of ecosystems that have the same climate and similar dominant communities
Biosphere

4. Levels of Organization – Fig. 3-2

5. Ecological Methods Observing – using your senses
Experimentation – may be set up in natural environment or artificial environment
Modeling – since some ecological phenomena occur over long periods of time or over wide areas
ecologists make models to duplicate phenomena
Can you think of some examples?

6. Energy Flow
Producers/Autotrophs – organisms that can produce food from inorganic compounds
Photoautotrophs – use light energy from the sun
to produce food through the process of photosynthesis (Fig. 3-5)
Chemoautotrophs – use energy stored within inorganic molecules to produce food through the process of chemosynthesis (light in not required) (Fig. 3-5)

8. Energy Flow
Consumers/Heterotrophs – can not synthesis their own food, rely on other organisms for energy
Herbivores – eat plants
Ominovores – eat plants & animals
Carnivores – eat animals
Detrivores – eat dead matter
Decomposers – break down organic matter

10. Feeding Relationships
Energy flows one way in ecosystems
Food chains – series of organisms through which food energy is passed Fig. 3 – 7
Food webs – food chains that are interconnected at various points Fig. 3-8
Trophic levels – step in a food chain or food web

12. Ecological Pyramids
Ecological pyramids show the relative amount of energy or matter contained within each trophic level – Fig. 3-9
Energy pyramid – only 10% of the energy taken in at one level is passed to the next (What happens to the other 90%)
Some food in not digested & absorbed
Some energy is used for respiration & maintenance
Biomass pyramid – total amount of living tissue at a trophic level
Pyramid of numbers – shows relative number of individual organisms at each trophic level

13. Energy Pyramid

14. Biomass Pyramid

15. Pyramid of Numbers

16. Cycles of Matter (Biogeochemical cycles)
Water Cycle
Carbon Cycle
Nitrogen Cycle
Phosphorus Cycle

17. Water Cycle – Fig. 3-11 Physical not chemical process
Water enters atmosphere through evaporation & transpiration
Water falls back to earth in some form of precipitation

18. Carbon (oxygen) cycle – Fig. 3-13
The cycling of these two gases results from photosynthesis, respiration, and decomposition
Combustion of fossil fuels & volcanic activity also releases CO2 into the atmosphere
What is the greenhouse effect?

19. Nitrogen Cycle – Fig. 3-14

20. Nitrogen Cycle – Fig. 3-14 N2 is used to from proteins & nucleic acids
N2 gas makes up approx. 78% of the atmosphere, however, plants can’t use N2 gas; some bacteria “fix” nitrogen gas into a form plants can use
Some N2 from decaying organic matter is converted by nitrifying bacteria into nitrates and nitrites which can be used by plants
Still other types of bacteria (denitrifying) convert nitrates into N2 gas  atmosphere

21. Phosphorus cycle – Fig. 3-15
Phosphorus is an major component of DNA & RNA
Most is stored in rock, soil minerals, and in ocean sediments

22. Nutrient Limitation & Primary Productivity
Nutrient limitation is a single scarce nutrient that limits the productivity of an ecosystem
Primary productivity is the rate at which organic matter is created by producers
Nutrient limitation can have an effect on primary productivity