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Unformatted text preview: Sheet1 Page 1 flow of enegery in an ecosystem-one way to follow the flow is to study who is eating who food chain- when a specisif group of producers is eaten by a specif group of consumers, then eaten by a group of consumers-energy is lost at each TROPHIC LEVEL, and will eventually run out large fishteritary carnivoresgets energy from other animals, primarily carnivores | Minnowssecondary consumers, energy from primary consumers aka from herbivores | Midge Larvaeprimary consumers, herbivoresenergy from tissues of primary producers | Green Algae primary producers, autotrophicgets energy from the sun(solar energy) food web - when one or more trophic levelobtain energy from and provide energy to two or more trophic levels resulting in a c set of energy transfers.minnows eat 2-3 things and 2-3 things eat minnows-organisms can be on more than one trophic level at once in a certain communtity, mice eat seeds and grass owls also eat rabbits. recreate. levels of organization-organismal-population-community-ecosystem-biome population ecology : branch of ecology that studies the activities of populations 1. Density of species interested in number of deer per sq. acre-this depends on the dispersion or distrubution pattern exhibited by the species. DISPERSION PATTERNS: 1. Random - individuals in a population are distrubuted randomly or hte presense of absense of one individual does not affect-not common 2. Regular - individuas are distrubted regularly or are uniformly distrubuted -not that common, but the ones that do hold territories. 3. Clumped - individuals of a population occur together and sometimes move as a unit from 2 location to another -herds, flocks, schools of fish, common. Sheet1 Page 2 These all affect the density of a species in an area.--Ways to measure density/Estimate population numbers 1. Direct count - count all the individuals within a definite boundry.-# of sea stars in a tide pool 2. Estimate population numbers - count all in a specific area and extrapolate.-indirect indicators - Number of nests, burrows-Mark recapture method -estimate the number of green frogs associated with a pond A= # of frogs collected at 1st collection time, 50 b= # of frogs collected at 2nd collection time, 100 c= # of frogs which were marked when captured, 10 A(50) x B(100) ______________ = 500 C(10) assumptions: no significant movements of individuals no significant births, deaths marks and tags are not lost "" "" do not increase mortality equal probability of marked invidiuals to be captured as unmarked 2. Study of movements: Emigration, Immigration, Migration - Leave and Return 3. population growth and numbers: how does a population grow in #/density thru time?????????...
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This note was uploaded on 03/18/2008 for the course BS 110 taught by Professor S.lawrence during the Fall '07 term at Michigan State University.
- Fall '07