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.

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

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

(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

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