28 Cards in this Set
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lotka volterra model
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differential equations to describe predator prey dynamics, characterized in oscillations in population size of both predator and prey where predator peak lags behind the prey
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assumptions of lotka volterra
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1. prey population will grow exponentially when predator absent
2. predator population starves in absence of prey (as opposed to prey switch)
3. predators can consume infinite quantities of prey
4. no environmental complexity (both populations moving randomly through homogenous environ…
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in the lotka volterra population model for a prey population, which process is directly affected by predators?
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deaths
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most important fact limiting primary production in the open ocean
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primary production: capture of light energy and its conversion to chemical energy
-aquatic systems are nutrient limited
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what is the open ocean limited by in primary production
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nitrogen and phosphorus
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what limits fresh water primary production
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phosphorus
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what are terrestrial environments limited by for primary production
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water, but can also be limited by fertilizers and nitrogen
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ecotones
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regions of rapid replacement of species along a gradient, clear community boundaries
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total energy assimilated by primary producers
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NPP + production in dark = GPP (gross primary production)
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a species diversity index, like simpsons takes into account
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number of species and relative abundance of species
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top down effects
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predator eats prey, prey population is reduced and indirectly increase the next lower trophic level
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keystone predator
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large impact on top down, must be there for other species to exist
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bottom up effects
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increased production results in greater productivity at all trophic levels
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NPP dependence on light and temperature
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there is a saturation point where photosynthesis will no longer exist! rate of photosynthesis will increase with temp up to a point (rate of respiration also increases), net assimilation will decrease at high temps
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limit on trophic levels in a food chain
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energy loss at each trophic level limits the number of trophic levels to 4-5 max (mostly around 3-5)
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what does competition do to K?
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decrease
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lowest net primary production ecosystem
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open ocean and subtropical desert
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highest NPP ecosystem
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algal beds and reefs then swamp and marsh
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trend between bivalve species diversity and earths latitude
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as latitude increases, diversity decerases
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species diversity correlations
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energy input: species richness increases with PET up to a threshold
complex habitats: more diversity
island further from mainland: less diversity
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leaf cutter ants relationship with fungus
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mutual, nitrogen is the limiting resource for fungus
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type I functional resposne
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predicts there is no upper limit to prey consumption assumed by lotka volterra models, reasonable over some ranges of prey density, may also be good for filter feeders, generally unrealistic due to satiation and handling time, linear
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type II dunctional respinse
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predicts prey consumption per predator levels off, allows for the effects of handling time, logarithmic (exponential)
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type II functional response
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prey consumption starts slow, picks up then levels off, highest consumption at intermediate prey density, at low density the prey can recover due to limited safe spaces, inexperienced hunters and prey switching, S curve
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photosynthetic efficiency of the ecosystem
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1-2%, remaining energy is reflected absorbed or dissipated, light is rarely the limiting resource
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pattern in island biodiversity
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island size and distance to mainland
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species richness
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number of species present
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assimilation efficiency
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assimilation/ingestion
function of food quality
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BIOL 301: Resource Partitioning