Chapter 53 Notes Community Ecology
What is a Community? A __________ is any assemblage of populations in an area or habitat. Communities differ dramatically in their species richness and relative abundance. - _______________: number of species contained - ____________________: number of different species
What is a Community? ________________: a community is a chance assemblage of species found in the same area because they have similar abiotic requirements. ___________________: assemblage of closely linked species, locked into association by biotic interactions.
What is a Community?
Interspecific Interactions and Community Structure ____________________: interactions belonging between populations of different species under one community Competition ___________________ for resources can occur when resources are in short supply
Interspecific Interactions and Community Structure
___________________________: - two species are so similar that they compete for the same limiting resources - one will use the resources more efficiently and reproduce more - this will lead to local elimination of the competitor Interspecific Interactions and Community Structure
________________ - sum total of a species’ use of biotic and abiotic resources in its environment - how a species “fits into” an ecosystem - where it is and what it does
Interspecific Interactions and Community Structure ______________________: - if a species will evolve to use a different set of resources - leads to a differentiation of niches
Interspecific Interactions and Community Structure Predation - includes the killing of one animal by another, herbivory, and parasitism - predator adaptations - plant defenses against herbivores - animal defenses against predators
Interspecific Interactions and Community Structure
- __________ ____________: animals with effective chemical defenses are brightly colored to act as a warning
Interspecific Interactions and Community Structure - __________ ___________: a species of prey will gain protection through mimicry
Interspecific Interactions and Community Structure ___________ is the symbiotic interaction in which the parasite derives its nourishment from the host - ______________: interaction that benefits only one of the species involved in the interaction
Interspecific Interactions and Community Structure - ___________: interspecific interaction that benefits both species
Interspecific Interactions and Community Structure Trophic structure is a key factor in community dynamics _______________: feeding relationship between organisms - food chains - food webs - trophic levels: links in the food chain
Interspecific Interactions and Community Structure
Food chains are limited to four or five links - ___________________: only 10% of the energy stored in organic matter is converted to the next trophic level
Interspecific Interactions and Community Structure Dominant species and keystone species exert strong controls on community structure ________________: species that have the highest abundance or biomass ________________: species that exert strong control on community structure by the ecological niches
Disturbance and community structure Communities follow an nonequilibrium model: they are seen as constantly changing after being rattled by disturbances - storms, fire, human events, etc.
Disturbance and community structure Ecological succession is the sequence of community changes after a disturbance ______________ succession: transitions of species composition over ecological time ___________ succession: begins in a lifeless area such as a new volcanic island
Disturbance and community structure _____________ succession: occurs when an existing community has been cleared by a disturbance that leaves the soil intact - early arrivals may facilitate, inhibit, or tolerate later arriving species
Biogeographic factors affecting biodiversity Two key factors correlated with a communities biodiversity are its _____ and _____________________ - small or remote islands have fewer species than large islands or those near continents