Community Ecology

• Predators– Carnivores and herbivores– All heterotrophs are either predators or

parasites or both– Adaptations

• Finding, capturing, and consuming prey

• Examples: acute smell, heat-sensitive pits, speed, flesh-cutting teeth, camouflage

Community Ecology

• Prey– Adaptations

• Resembling an inedible object• Hiding• Deceptive markings

– Fake eyes, false heads

• Chemical defenses• Mimicry

– King snake and the deadly coral snake

• Plants- thorns, tough leaves, chemical defenses

Symbiosisclose, long-term relationship between

two organisms• Parasitism

– Lice, leeches, fleas, ticks, mosquitoes– Heartworms, tapeworms, disease-causing

protists

• Mutualism– Ants and acacia tree– Pollinating insect and flowering plants

• Commensalism

Ecological Succession

• Gradual, sequential regrowth of a community of species in an area

• Primary succession– Development of a community in an area that has not

supported life previously• Sand dune, bare rock, volcanic island

– Soil is not initially present

– Slow process

– Lichens Grasses Mosses and large plants Trees

Ecological Succession

• Secondary succession– Occurs where an existing community has been cleared

by a disturbance, but the soil has remained intact• Forest fire, storms, farming, logging, mining

– Original ecosystem returns through a series of well defined stages

– Example Eastern temperate regions: weeds (annual grasses, dandelions) perennial grasses and shrubs trees (dogwoods) deciduous forest community

Climax Community

• Stable end point• Organisms in each stage alter the environment in

ways that makes it less favorable for them to survive, but more favorable for the organisms that eventually succeed them.

• Each stage paves the way for the next• Leading to the climax community, which remains

constant for a long time.