Interactions of Organisms
Make two lists: Living and Nonliving
What is Ecology? Study of interactions between organisms and their environments Many factors affect the interactions of organisms: Abiotic Factors (nonliving factors)—water, temperature, light, nutrients Biotic Factors (living factors)—other organisms living in the same environment
4 Levels of Ecological Study Population Group of individuals of the same species living in a particular area Community All the organisms living in a particular area Ecosystem A community along with all abiotic (nonliving) factors in a particular area Biome Major terrestrial area and their ecosystem
Example of organization… Population Coyote Population Community All the organisms living in the desert (coyotes, snakes, cacti, sage brush, hawks, etc) Ecosystem community + the abiotic factors (water, air, soil, etc) Biome The complete Desert Biome
Size of a Population Size can be affected by: Birth Rate (natality) Death Rate (mortality) Immigration: movement into an area Emigration: movement out of an area Stable Population…population with no overall growth Births + Immigration = Deaths + Emigration
Name two factors that can cause a population to grow. What is the difference between emigration and immigration? What term is used to represent all the living organisms in an area? What is meant by abiotic factors?
Interactions Within a Community Competition Predation Symbiosis
Competition Competing for… Interspecies Competition Food, water, shelter, homes, space Interspecies Competition Competition BETWEEN different species Intraspecies Competition Competition WITHIN the same species
Predation: Predator-Prey Interaction Interaction between species when one organism is the resource (food) of the other What is it? The size of the population of each is dependent on the other Lots of prey….increase in predators Lots of predators…..decrease in prey
Symbiosis Interaction of two organisms living together Mutualism Both Benefit Commensalism One benefits—One unaffected Parasitism One benefits—One harmed
1. Mutualism Both organisms benefit from the interaction Examples: Flowering plants & Insects Nitrogen-fixing Bacteria & Legume plants
2. Commensalism An interaction when one benefits while the other is neither harmed nor benefited Usually physical attachment of the benefiting organism to the other (host) Barnacles & Sea Animals Protection Food Source Tropical Fish & Sea Anenomes Protection Not affected by the stinging tentacles of the sea anenome
3. Parasitism An interaction when one benefits while the other is harmed Benefiting organism: parasite Harmed organism: host Examples: Lice Tapeworms