1. Unit 8 Notes: Ecosystems & Energy

2. (1) Ecosystem Organization
The Organism: The most basic level.
A Population: A group of similar organisms living in an area together.
A Community: A bunch of different populations living in an area together.
An Ecosystem: The combination of all of the living, and nonliving factors in an area together.
A Biome: All of the different ecosystems within a climate-region. 2

4. (2) Parts of an Ecosystem
Biotic Factors: The living parts. (Either currently or once living.)
Examples  Plants, Animals, Bacteria, etc.
Abiotic Factor: The nonliving parts.
Examples  Climate (Temperature / Precipitation), Rocks and Minerals, Inorganic Compounds etc. 4

5. (3) Types of Organisms in Ecosystems
Herbivores: Organisms whose diet consists of plant matter.
Carnivores: Organisms whose diet consists of animal matter.
Omnivores: Organisms whose diet consists of both plant and animal matter.
Detritivores: Organisms whose diet consists of dead plant/animal matter.
Decomposers: Organisms who metabolize plant / animal matter, releasing their compounds back into the ecosystem. 5

6. (4) Matter & Energy As One Organism Consumes Another:
The matter they are composed of changes form and is transferred to new cells.
The energy within the bonds of molecules is transferred to new cells.

7. (5) Autotrophs  Heterotrophs
Autotrophs take unusable energy (from sunlight / chemicals) and convert it into stored energy in sugars.
Heterotrophs eat autotrophs + each other to get stored energy from sugars.
As energy is transferred from organism to another…
Less energy is available for the next organism.
Some energy is lost to the environment.

9. (6) Food Chains & Webs
Diagrams used to show the flow of energy, between organisms in an ecosystem.
Food Chains show the flow of energy through a single sequence of organisms.
EXAMPLE: Sun  Grass  Cow  Human
Food Webs show ALL of the energy relationships within an ecosystem.
EXAMPLE:
Human
Wolf
Cat
Cow
Bird
Ant
Grass
Flower
Sun

10. (7) Trophic Levels 1st 2nd 3rd 4th
Trophic Level = Step in a food chain or food web.
Lower Trophic Levels = More Energy & Larger Biomass Higher Trophic Levels = Less Energy & Smaller Biomass
Example: Grass  Grasshopper  Lizard  Hawk
1st
2nd
3rd
4th

11. (8) Energy Pyramids
Diagram to show the amount of energy and biomass per level in the ecosystem.
Biomass: Quantity of living organisms within a level.
The Trophic Levels:
The Base = Trophic Level 1 = Photosynthetic Organisms
2nd Level = Trophic Level 2 = Herbivores
3rd Level = Trophic Level 3 = Omnivores
The Top = Trophic Level 4 = Carnivores + Top Predators

12. 4th Trophic Level 10% of energy moves to next level 3rd Trophic Level
2nd Trophic Level
1st Trophic Level
July 22, 2012
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