1. Unit Two Ecological Interactions
Chapter 4
Matter and Energy in the Ecosystem

2. ROLES OF LIVING THINGS
Consumers
Producers
Decomposers

3. Producers – Autotrophs
Organisms that make their own food from inorganic molecules and energy from the sun
auto = self troph = feed
Photosynthesis – the chemical process that produces sugar from CO2 and energy from sunlight
protists – phytoplankton
plants – corn, rice, grass, wheat)

4. Consumers – Heterotrophs
Organisms that must eat food for energy
hetero = other
troph = feed
Herbivores – organisms that eat only plants (cows)
Carnivores – organisms that eat only herbivores or other carnivores (wolves)
Omnivores – organisms that eat both plants and animals (bears; humans)

5. Decomposers
Wood ear
Bacteria and fungi that consume the bodies of dead organisms and organic wastes
Decomposers complete the cycle of matter in the ecosystem
Ex:
Fungi: wood ear, portabella
Bacteria: E. coli, Salmonella
Portobello
E. coli
Salmonella

6. Trophic Levels A layer of the feeding relationships in an ecosystem
First level – producers
Second level – herbivores
Third level – first order carnivores
Fourth level – second order carnivores
Each level completely depends on the level below it

7. Ecosystem Structure Food Chain
A series of organisms that transfer food between trophic levels of an ecosystem
Always begins with producers
Decomposers supply the nutrients that begin the cycle

8. Ecosystem Structure Food Web
A network of food chains representing the feeding relationships among organisms in an ecosystem
Changes in any organism affects the other populations

9. FACTORS THAT AFFECT THE ECOSYSTEM
ABIOTIC
BIOTIC
WEATHER
CLIMATE
SOIL QUALITY
AVAILABLILITY OF FRESH WATER
POLLUTION
CONTAMINATION
PLANT LIFE
BIODIVERSITY
ANIMAL POPULATIONS
HUMAN ACTIVITY

10. BIOTIC FACTOR: BIODIVERSITY
The number of connections in a food web varies in every ecosystem (few species in the polar ice caps to many in the tropical rain forest)
The older or more complex food webs are more stable and are more resistant to natural or man-made disasters

11. ABIOTIC FACTOR: BIO-MAGNIFICATION
Ex: The pesticide DDT was used to control the mosquito population. Fish ate the sprayed mosquitos and their larvae which concentrated the DDT in the bodies of the fish. Eagles ate the contaminated fish. This caused the eagles to have defective shells and eggs broke decreasing the number of eagles being born.
Pollution or chemical contamination that can be magnified in a food web
The concentration of a pollutant in organisms increases as it moves up the trophic levels in a food chain.

12. Energy in the Ecosystem
Ecological pyramids –show the relative energy in each trophic level
Energy is NOT a renewable resource
Energy, biomass or number pyramids decrease in value as you move up the trophic levels
This means each trophic level gets less energy fro the food they consume than the previous level

13. Energy in the ecosystem
BIOMASS – shows total amount of organic matter (energy) present in a trophic level
Energy travels between one trophic level and the next in the form of food.
10% LAW – producers store 30% or LESS of sun’s energy, each trophic level after that only gets 10% of the available energy from the trophic level before.

14. Chemical Cycles
96% of your body is made up of four elements: carbon, oxygen, hydrogen, nitrogen
Elements move the ecosystem in cycles
Matter cycles repeatedly through the ecosystem
The amount of matter that enters and leaves each cycle is small

15. Water Cycle
Water Cycle – water moves between ocean, atmosphere and land
Evaporation – water changes from liquid to a gas, moves into atmosphere
Transpiration – evaporation of water from leaves of plants
All of the fresh water we will ever have is already here

16. Carbon Cycle
Producers (plants, bacteria and plankton) produce sugar using energy from the sun in a process called photosynthesis
H2O + CO2 = C6H12O6 + O2
Consumers use the energy from food in a process called respiration
C6H12O6 + O2 = H2O + CO2

17. Nitrogen Cycle
Nitrogen is necessary to make amino acids – the building blocks of proteins
Nitrogen is usually found as a gas in our atmosphere
Bacteria help to convert nitrogen gas to ammonia and nitrates
Legumes (peas, beans, peanuts) have specialized bacteria in their roots that covert nitrogen gas from the atmosphere into nitrates which can be used by plants to make amino acids