1. Chapter 3: The Biosphere
What is ecology?

2. Ecology
Ecology – the study of interactions among organisms and between organisms and their environment
Interdependence – dependence of every form of life on other living things and natural resources (air, water, land) in its environment

3. Levels of Organization
Biosphere – largest, portions of planet where life exists (land, H2O, air)
8 km above to 11 km below
Biome – group of ecosystems with same climate (temp. and rainfall)
Ecosystem – collection of all organisms in a particular place together with the abiotic (physical) environment.

4. Levels of Organization
Community – groups of different populations that live together in a defined area.
Population – groups of individuals of same species in same area.
Species – group of organisms so similar that they can mate and produce fertile offspring.

5. Levels of Organization

6. Biotic and Abiotic Factors
Biotic – living
Plants, Animals ,Mold, Fungi, Bacteria, Protist
Abiotic – Nonliving
Sunlight, soil, wind, water, temperature
Habitat – the area where an organism lives; includes both biotic and abiotic factors.

7. Ecological Methods Observation – 1st step to designing an experiment
Experiment – test hypotheses; imitate & manipulate
Modeling – make models based on observation & experiment
Helps make future predictions

8. 3.2 ENERGY FLOW (Autotrophs and Heterotrophs)
One of the most important factors to determine capacity to sustain life is Energy Flow

9. Autotrophs (producers)
Can trap light energy to produce food (organic molecules)
Plants
Some protists
Some bacteria
Photosynthesis – captures solar energy and converts it to chemical energy
6CO2 + 6H2O C6H12O6 + 6O2
Chemosynthesis – Chemical energy used to produce carbohydrates
SUN

10. Heterotrophs (consumers)
Can’t trap energy directly; must acquire it from other organisms
Herbivores – plants
Carnivores – animals
Omnivores – both
Detritivores – remains of dead plants & animals
Decomposers – break down organic matter

11. 3.2 Energy Flow in Ecosystems
Food Chains and Food Webs

12. Food Chains and Food Webs
SUN Autotrophs Heterotroph
Food Chain – energy trapped by producers passed on when organisms eat and are eaten
Food Web – relationship more complex than a chain

13. Trophic Levels and Ecological Pyramids
Trophic Levels – each step in a food chain/web
Ex: producers, then consumers
Ecological Pyramids – shows relative amount of energy at each level (10% rule)
Biomass – total amount of living tissue within a trophic level

14. Trophic Levels and Ecological Pyramids

15. 3.4 Cycles of Matter
*Recycle Matter*

16. Carbon Cycle Photosynthesis – uses CO2 from atmophere
Happens in the CHLOROPLAST
6CO2 + 6H2O C6H12O6 + 6O2
Respiration – returns CO2 to atmoshere
Happens in the MITOCHONDRIA
C6H12O6 + O2 H2O + CO2

17. Carbon Cycle

18. The Carbon Cycle
Volcanoes, respiration, fossil fuels, and decomposition add CO2 to atmosphere.
Plants take CO2 and make carbohydrates
Plants are eaten by animals and carbohydrates are passed through the food chain.
As the animal breathes and eventually dies and decomposes CO2 is return to atmosphere.

19. Water Cycle

20. Water Cycle Water enters the atmosphere by:
Evaporation – water changes from a liquid to a gas
Transpiration – Evaporation through leaves
As water rises it cools condenses into tiny droplets that form clouds.
Droplets returns to Earth as precipitation.
Water enters the rivers, ground water, ocean or plant roots to restart cycle.

21. Nitrogen Cycle

22. Nitrogen Cycle Nitrogen gas makes up 78% of atmosphere
Nitrogen Fixation: bacteria take nitrogen gases and turn it into ammonia, nitrite, and nitrate.
Plants and animals use nitrate to make amino acids.
Animal dies and decomposes returning nitrates to the soil.
Denitrification: other bacteria convert nitrates into nitrogen gas.

23. The Phosphate Cycle Phosphate – parts of DNA/RNA
Found in rocks that are worn down
Washes into rivers/streams/oceans for marine organisms
Taken in by plants and turned into organic compounds

24. Nutrient Limitation
Primary Productivity – the rate at which organic molecules are created by producers
If nutrients are in short supply, they are called LIMITING NUTRIENTS
Ex: Nitrogen is often limiting in water; if there is suddenly as input of N (fertilizer runoff), organisms can grow rapidly (Algal Bloom)

25. Discussion questions:
How many stops can you make on your trip?
Will your journey ever end?
Was everyone’s journey the same? Why not?
What would happen if a farmer used too much fertilizer? (In this game, that would mean that everyone started from the fertilizer station at the same time.)
Livestock farming creates a large amount of animal waste. How would this affect the nitrogen cycle?