1. Energy Transfer
Sun
Producers
Primary Consumers
Secondary Consumers
Tertiary Consumers
Decomposers
*Only 10% of the energy in one level is converted to biomass at the next level. The rest of the energy (90%) is lost as heat/waste.

12. Interactions in an ecosystem
Predator/Prey
One organism eats another
Symbiosis
Close relationship between organisms
Parasitism: one
organism
benefits while
harming the other
Commensalism: one
organism obtains a
benefit from the other,
other is not harmed
Mutualism: both
organisms are helped
Ex: Frog eats fly
Ex: tapeworm
in human
Ex: shrimp in
sea anemone
Ex: birds on
rhino’s back

13. Summary of Symbiotic Relationships
Term
Species #1
Species #2
Parasitism
Benefits
Harmed
Commensalism
No effect
Mutualism

14. (optimum # of a species that can
Population Growth
Slow growth period
Exponential growth
Growth slows
(population does not drop)
Steady state
(birth rate = death rate)
E. Carrying Capacity
(optimum # of a species that can
be supported by the environment)
Time
Population A B C D E

15. Limiting Factors Density-dependent limiting factors
A condition that affects a population’s growth
Density-dependent limiting factors
Density-independent limiting factors
Predation
Competition
Parasitism
Crowding/Stress
Temperature
Weather
Fire
Floods
Food, mates