Unit 8 Notes: Ecosystems & Energy

(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

(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

(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

(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.

(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.

(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

(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

(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

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