Transcript Competition
Competition Hey! You! Get off of my cloud! Terminology • Resources – Something that can be used – Food, water, mates, a place to grow (for organisms like plants, mussels, etc.), a hiding place or other shelter, basking sites – Renewable or non-renewable – Limiting resource (in short supply) • Conditions – Temperature, pH – Can’t be used up Niche • The functional relationship of an organisms to its physical and biological environment • Niches are multidimensional • Range of physical factors for survival / reproduction – Temperature, humidity, pH, soil, sunlight, shelter • Biological factors – Predators, prey, parasites, competitors (food resources) • Behavior – Seasonality, diurnal patterns, movement, social organization – Ex. - burrowers, nocturnal, migration, social, herd • If each of these parameters represents a niche, then whenever two species share the same parameter, competition for that resource occurs Competition • Intraspecific competition – – – – Occurs within the species 100% niche overlap here is near 100% All resource (niche) requirements are the same Strongest competition • Interspecific competition – Competition between species – Only a few resources are shared – Ex. – Squirrels and chipmunks • Food resource is shared, breeding and nesting is not Competitive Exclusion • Two species competing for the same limiting resource in an area cannot coexist – In general, when two closely related species occupy the same area, they will eventually compete for a ‘limiting resource’ – One species will be better at the competition and will eventually displace the other – Two species cannot occupy the same niche • There will always be a difference Forage on the same trees for insects The nuthatch moves DOWN the trunk when foraging The creeper moves UP the trunk Each encounter, see and eat totally different insects Resource Partitioning Limiting competition Competition and Evolution • Better competitors get more resources – Better able to survive – Better able to reproduce – Better able to pass on their genetics • Genetics of the weaker competitors are lost Direct Competitors? • Green Anole – Anolis carolinensis – Native to Fla. • Brown Anole – Anolis sagrei – Introduced (circa 1890) • Greens dominate natural settings • Browns more common in the human domain • Is time a factor?? American Alligator • Freshwater • Were threatened • Regulated hunting • Rebounded population American Crocodile • • • • Saltwater Endangered Smaller habitat Greater human impact