Chapter 55: Community Ecology
What are ecological communities?
An ecological community consists of all the species that live and interact in a given
Species tend to be grouped together
However, different species can lives with various species, overlapping and underlying
depending on the area
Species are categorized based on energy source
Food chains are developed through food webs
Most communities share the fact that they have only 3-5 trophic levels
oWhy? because as energy (BIOMASS) passes through different levels, some
energy is lost in different ways
oMost energy is held at the primary producersprimary
oVariations of biomass depends on community
What processes influence community structure?
Types of Ecological interactions:
1.Predationoscillating effect (if there are more predators, extinction of
prey might is common. If there are more prey and very little predators,
the prey species will be over-crowded)
2.Parasitesfeed on the host without killing it
3.Competitioninfluences abundance and distribution of species; two
organisms using the same resource that is insufficient to supply needs of
an ecological community consists of all the species that live and interact in a given area. however, different species can lives with various species, overlapping and underlying depending on the area. species are categorized based on energy source: autotrophs, heterotrophs. because as energy (biomass) passes through different levels, some energy is lost in different ways: most energy is held at the primary producersprimary consumerssecondary consumers, variations of biomass depends on community. Types of ecological interactions: predationoscillating effect (if there are more predators, extinction of prey might is common. I nterference competitionone species interferes with the activates of another: exploitation competitionone species reduces the availability of resource. Trophic cascades: combination of all relationshipsone species affects another and so on, human intervention can disrupt species and all those related to it (for various reasons) disturbancean event that changes the survival rate of one or more species, with varying impacts.