Lesson 2: Energy Flow Through Ecosystems

Physical Aspects in an Ecosystem

BIOTIC FACTORSBio means “life”Living organisms

PlantsAnimals

ABIOTIC FACTORS“A” means “notNot living things

RocksWindSunWaterDirt

Symbiotic Relationships

• Mutualistic: both partners benefit

• Commensalistic: one partner benefits and the other partner doesn’t care

• Parasitic: one partner benefits and the other is harmed

• Predatory: predator/prey…one partner is the dinner for the other

10 % RuleOnly 10 % of the energy or biomass at one

trophic level is passed on to the next

A food chain, shown above, shows one path the energy can take.

Wheat Mouse

Snake Owl

A food web is a collection of several food chains, linked together.

A food (or energy) pyramid is another way to represent this information. The pyramid gets its shape from the fact that the greatest amount of energy in the ecosystem is stored in the producers. (There is more grass than grasshoppers, and there are more grasshoppers than frogs.) There are very few tertiary consumers in ecosystems because it takes a lot of energy feed one.

Toxins(poisons) can build up in the food chain. They are the least concentrated in the producers, but can build up in the bodies of animals as they feed. The higher an animal is on the food pyramid, the more poision he has consumed.

Lesson 4: Viruses and Bacteria

                                    

                                                                                                             

Viruses• ARE NOT LIVING!

• Only can reproduce inside host cell

• Cell Specific- will only bind to certain cells– Polio virus only attaches to human nerve cells

Viruses

• Viral infection must run their course- NO ANTIBIOTICS!

• There are vaccines that can prevent some viral infections, like Hepatitis A or B, influenza and chicken pox.

• An organism’s immune system is designed to fight viruses with fever & antibodies.

Viruses destroy host cell!!

Viral diseases

• HIV/AIDS: Destroys Helper T cells of the immune system

• Influenza and common cold: spread by contact

Bacteria shapes

A. Coccus: round or spherical

B. Spirillum: spiral-shaped

C. Bacillus: rod-shaped

Coccus Bacillus Spirillum

Bacterial arrangements

Diplo- : paired cells

Staphylo- : grapelike clusters

Strepto- : long chains

Diplo-

Strepto-

Staphylo-

Bacteria

Good Types• Used in Nitrogen cycle

(Rhizobium)

• In food (lactobacillus)

• In digestive system (E. coli)

• Decomposers

Bad Types• Cause disease

– Strep throat– Diphtheria