Chapter 54: Community Ecology Flashcards
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What are interspecfic interactions?
- def: relationships between species in a community
- examples: competiton, predation, herbivory, parasitism, mutalism, & commensalism
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What is competition?
- species compete for a resouce that are short in supply
- can limite survival and reproduction
- competitve exclusion: when strong competition cause local elimiation of competing species
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What is an ecological niche?
- the sum of an organism’s use of biotic & abiotic resources
- an organism’s ecological role
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What is resource partitioning?
when similar species coexist in a community despite differentiation in ecological niches
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What is the difference between an organisms’s fundamental and realized niche?
- fundamental niche - potentially occupied by that species
- realized niche - actually occupied by that species
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What is exploitation?
- def: any interaction in which one species benefits by feeding on other species
- these interactions include: predation, herbivory, & parasitism
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What is predation?
- one species (predator) kills & eats the other (prey)
- predators have adaptations that help them find & catch their prey
- prey have adaptations to avoid being eaten
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What are examples of these defense adaptations
- mechanical defense & chemical defense
- apopsematic coloration: warning color
- batesian mimicry
- cryptic coloration: camouflage
- mullerian mimcry
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What is herbivory?
- herbivore eats parts of a plant/alga
- herbivores have specialized adaptations
- plants may produce toxins & mechanical defenses as protection
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What is parasitism?
- parasite derives nourishment from host w/ harming it
- endoparasites live in body of host
- ectoparasites live on surface of host
- parasites can directly/indirectly affect survical & density of host population
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What is mutalism?
- both specis benefit from interaction
- some species depend on the other for survival/reproduction
- ex: a bee pollinates a flower for honey; bee carries pollen to another flower which helps plant reproduction
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What is commensalism?
- one species benefits and the other is harmed nor helped
- ex: wildfowers depend on shade provided by trees; trees are not affected
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What is species diversity?
- variety of organisms that make up a community
- two components
- species richness: # of different species in community
- relative abundance: proportion each species respresents of all individuals in the community
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Communities w/ high diversity are…
- more productive
- more stable
- can withstand & recover from environmental stresses
- more resistant to invasive species
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What is the trophic structure?
- the feeding relationships between organisms in a communty
- can greatly affect community structure & dynamics
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Food chains
- link trophic levels from producers to top carnivores
- limits of food chain length: energetic hypothesis, large carnivors at high trophic levels
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What is a food web?
- group of food chains linked together forming complex trophic interactions
- similar trophic relationships are grouped into broad functional groups
- isolate portion of community that interacts very little w/ rest of community
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What is energetic hypothesis?
- suggests that length is limited by inefficient energy transfer
- 10% of energy stored in matter at each trophic level is convered to matter at next level
- ex: 100kg - 10 kg -1 kg
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What is the difference between dominant & keystone species?
- dominant: most abundant; have highest biomass
- keystone: exert strong control on community; arent necessarily the dominant ones
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What is the bottom-up model?
- unidirectional influence from lower to higher trophic levels
- nutient levels limit plants, plants limit herbivores, herbivores limit predators
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What is the top down model?
- proposes control coming from trophec level above
- predators limit herbivores, herbivores limit plants, plants limit nutrient levels
