Community Ecology Campbell Chapter 53

What is a community? All the populations in a given area interacting with each other and their surrounding environment.

Interactions between species These are interactions between different groups of organisms

Competition Organisms compete for the same resources: Food, space, mates From

Competitive Exclusion Principle (Gause’s) Two similar species cannot exist in the same niche One will be driven to extinction

Symbiotic relationships Two organisms living together in a relationship

Predation/parasitism One organism feeds on another for food One is benefited, one is harmed From

Herbivory Type of predation done by herbivores Herbivores preying on plants From

Secondary Compounds in Plants Plants can’t run away, so they produce toxins to deter herbivores Ex. aspirin, clove oil From

Commensalism Two organisms live together, and one is helped while the other is not affected Ex. hermit crabs From

Mutualism Two organisms benefit from living together Ex.: ladybugs eat aphids on rosebushes From

Ways to avoid predation Animals have adaptations to avoid being eaten.

Aposematic Coloration “Warning” coloration Bright colors warn others “I taste bad/I bite/I am not to be messed with” From

Cryptic Coloration Coloring that allows the organism to blend into its environment so it can’t be spotted by predators From

Mimicry Some organisms mimic others in order to protect themselves

Batesian Mimicry A harmless or palatable species mimics one that is neither harmless nor palatable

Example: Hawkmoth and Snake When disturbed, the hawkmoth larva looks like a snake.

Mullerian Mimicry Two unpalatable species mimic each other

Example: Monarch vs. Viceroy Butterflies From From year.com/nature/showphoto.php?photo=17870 Monarch butterflies taste bad too so birds try to avoid them as well. Viceroy butterflies taste foul to birds and will make birds regurgitate them when eaten.

Example: Honey Bee and Yellowjacket From From ACKET%201%20SEPT.%2025,%2005%20135F1366b.jpg Both species share similar coloring and have poisonous venom

Succession The replacement of one community with another

Primary Succession A community is established in a fairly lifeless area First life forms are usually bacteria, then lichens Soil eventually develops, then plants are established

Example of primary succession A retreating glacier leaves a moraine, a soil-laden area where life has the potential to take root.

Secondary Succession Occurs in an area where disturbance has occurred, but the soil is intact After a forest fire After a hurricane

Example of secondary succession