Interspecific interactions Competition (-/-) Predation (+/-) Herbivory (+/-) Symbiosis Mutualism (+/+) Commensalism (+/0) Parasitism (+/-)

Niche An area (environment) where an organism utilizes the biotic and abiotic resources; ecological role Resource Partitioning Character displacement Diff in body structures and the resources they use Darwin’s Galapagos finches  adaptations for eating diff sized seeds Competitive exclusion principle No two species can occupy the same niche at the same time, competing for the same limiting resources

Predator kills another, it’s prey Adaptations Predator Claws, teeth, fangs, stingers, venom (poison) Prey Cryptic coloration = camouflage Aposematic coloration = chemical defenses w/ bright color patterns Batesian mimicry = harmless sp resembles harmful one Mullerian mimicry = 2+ harmful sp resemble one another

Organisms eat parts of a plant or algae Smell and chemical sensors allow for distinction btwn harmful (toxins) and harmless Specialized Teeth

Mutulism (+/+) Both members benefit Commensalism (+/0) One member benefits, other neither helped nor harmed Parasitism (+/-) One member benefits, other is harmed

Species diversity = species richness --. Biodiversity Invasive Species threaten biodiversity Biomass = total mass of individ in a population Trophic structure = feeding relationships w/in a community where only 10% of available energy is passed to next trophic level, as seen in food chains and then food webs Dominant species = most biomass in a population Keystone species = not nec abundant, but have significant control over their ecological role Sea otter Bottom up Model Nutrients control  vegetation  herbivores  predator # Top down Model Predator #  herbivores  vegetation  nutrients

Disturbance Moderate levels of disturbance can foster higher species diversity than can low or high levels of disturbance Ecological succession Facilitation & Inhibition (early arrivals facilitate appearance of later arrivals / early arrivals may inhibit later colonization of later arrivals) Primary No soil exists (after fire) Secondary Soil remains after a disturbance (melting glaciers) Humans

Species richness declines from tropics  Polar regions Climatic influences on sp richness through energy and water Geographic size influences sp richness

Pathogens in terrestrial and marine comms Human activities influence (swine & avian flu)