Ecology: Community Structure and Interactions Flashcards
Species
Can interbreed and produce viable offspring
Population
All members of one species in same time & place
Community
All populations in same time and place
Ecosystem
a biological community of interacting organisms and their physical environment.
- includes biotic (living) and abiotic (nonliving) factors)
Trophic Interactions
-movement of energy; depends on solar interactions and is an open system- there is always input from the sun
-different from a cycle -> closed systems with finite amount of resources
Rule of ten
-Ten percent of the energy at one trophic level is transferred to the next one up the pyramid.
-Contrast with concept of biomagnification, where something is concentrated as it moves up the various trophic levels.
What are the 5 types of community interactions/relationships
-competition, predation, parasitism, mutualism, symbolism
Competition
(-/-) both parties negatively affected
-species compete for resources (food, habitats, space)
Predation
(+/-) one benefits, one does not
-Strategies to obtain prey (ex. Chasing)
-Strategies to avoid being eaten (ex. Camouflage)
Parasitism
(+/) one benefits, one does not
ex. tapeworms/heartworms
Mutualism
(+/+) both benefit
-plants/pollinators
-bees and many others
Symbolism
(+/+) both not only benefit, they are totally interdependent on one another
-Organisms are in such a close relationship they can’t live without each other.
- Lichens are a symbiotic relationship between an alga (provides sugars from Ps) and a fungus (provides increased nutrients/H2O absorption)
Keystone Species
-A species whose role in ecosystem is disproportional to abundance or biomass
-Removal of the keystone species would dramatically change the entire community
ex. The Pisaster Starfish in rocky internal communities of western north USA -> species diversity dropped when it wasn’t present
