APES Communities, Populations, Interactions - Shope

• species
o organisms that are similar in nature and are capable of interbreeding and producing fertile offspring
- generalist species
• those with a broad niche
• can survive under varied conditions
- specialist species
• live in narrow, specific niches
o examples…
- horse and donkey are different species… their offspring (mule) is infertile
- all dogs are the same species

• population
o all members of a species living in a certain area

• community
o all of the different species (populations) living in a certain area

• niche (rhymes with “rich”)
o the lifestyle of species… where and how it lives
- fundamentalist niche
• the potential life if all parameters are optimal
- realized niche
• actual life of a species (after competition)

• species within ecosystems
o native
- organisms that normally live and thrive and have done so for some time
o nonnative
- a.k.a.: alien, exotic, invasive
- organisms that have been brought into an area, usually as a result of human activity
o indicator
- a species that can work (‘provide’) as an alert or warning of a problem
- ex. amphibians – occupy two habits (land & water)
o keystone
- a species that is more important than its biomass or abundance would indicate
- some people believe that there are no true keystone species
- alligator may be a keystone species

• competition
o interspecific
- a.k.a.: niche overlap
- competition between different species for the same resource
- predation
o symbiosis
- “same life”
- parasitism – one harmed, one benefited
- mutualism – two benefited
- commensalism – one benefited, one indifferent