Community Ecology Pt2

an assemblage of populations living close enough together for potential interactions

Number of species in a community (species diversity)

how many individuals are in each of those species

Individualistic: species are independently distributed an it is just chance that they have similar abiotic requirements Interactive: communities are groups if particular species that are interdependent & occur together

Interactions between populations or species within a community

the preying of one animal on others (+/-)

the interaction of individuals that vie for a common resource that is in limited supply (-/-)

One species benefits and the other is not harmed (+/O)

Both organisms benefit (+/+)

Blend in! These Organisms blend into their environment so it decreases the chance they will be found

Bright coloration warns others that they can do some damage if attacked

A harmless species looks like a harmful species. Predators will think they are the “bad” kind and not eat them

Two species that are BOTH harmful look like each other

• Interference and 2. Exploitative

Actual fighting over a resource

Consumption or use of similar resources

Lotka & Volterra claimed: 2 species with similar needs for the SAME limiting resources CAN NOT coexist in the same place ex: paramecium & Gause’s experiment

Sympatric species (live in the same area but cannot successfully mate) consume slightly different foods or use other resources in a slightly different way ex: bird species using different areas of the tree

sympatric species tend o diverge in those characteristics that overlap ex: Darwin’s finches & beak size (different sized food so they can coexist)

transition in species composition overtime

Begin in a lifeless area without soil ex: volcanic activity or retreating glacier

An existing community has been cleared by some disturbance that leaves the soil intact ex: flood