Notes for 11/16-11/23
Notes for 11/16-11/23 BSC 116
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This 0 page Class Notes was uploaded by Rani Vance on Wednesday November 25, 2015. The Class Notes belongs to BSC 116 at University of Alabama - Tuscaloosa taught by a professor in Fall 2015. Since its upload, it has received 8 views. For similar materials see Principles Biology II in Biological Sciences at University of Alabama - Tuscaloosa.
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Date Created: 11/25/15
BSC 116 11161123 Lecture 37 Ecology is the study of how organisms interact with one another individual popuation group of individuals of same species communitiesgroups of population ecosystemsgroups of communities andscapesgroups of ecosystems goba the earth biosphere Ecology amp Evolutionary Biology evoutionary time populations to adapt to environments ecoogica time response of organism populations to their environments Why are species distributed the way they are no species occurs everywhere even people ie red kangaroo only found in some places many factors determine this dispersa behavior biotic living things predators prey pathogens competitors abiotic physical factors temp light water Species distributions based on other organisms other organism biotic factors species absent because other species is missing ie food host pollinator species absent because other species is present ie predator parasite competitor Species distributions limited by physiological tolerances incudes physical and chemical propertiesabiotic factors temp too hot or too cold species adapted to one extreme cannot exist in another water too wet too dry salinity osmotic issues sunight important for photosynthetic organisms geoogy inorganic parts of the habitat minerals pH physical structure of land earth is not homogenous for abiotic factors eads to variation in biotic factors many abiotic factors climate long term prevailing weather conditions Variations in climate proximity to water effects temp and humidity coastal areas are moister than inland of same latitude air changes temperature faster than water mountain effects shadow to sunlight atitude temp quotrain shadowquot warm air passing mountains cools and drops moisture occurs in deserts tilt of earth results in predictable seasonality leads to variation in day length sunlight and temp Biotic and abiotic factors combine to form biomes biomes major habitat types determined by both biotic and abiotic factors atitudina variation in temp moisture leads to latitudinal variation in animals and plants ecotones areas of transition between biomes disturbance leads to community variation patchiness ie res hurricanes etc Aquatic biomes are characterized by salinity and depth Lecture 38 Population Ecology Population conspeci c individuals occurring in a particular area ive in same environment use same resources interactbreed with each other Populations are dynamic always changing gain individuals from births gain individuals from immigration arriving ose individuals from deaths ost individuals from emigrations leaving 3 characters to describe populations density number of individuals per unit area volume boundaries dif cult to nd dispersion pattern of spacing among individuals cumped aggregated in patches attracted to resources uniform evenly spaced random independent of other individuals demographics age and sex structure of the population Survivorship curves survivorship curve number alive plotted vs each yaxis plotted on a log scale species have characteristic survivorship curves depending on life history pattern of reproductive and survival ie humans low constant death rate until late in life type I put energy into raising their children ie oysters high death rates early on low for survivors type III energy into producing many offspring without parental care survivorship is a factor that determines population size BE ABLE TO APPLY A POPULATION TO A SENSORSHIP CURVE Reproductive rates are as important as death rates reproductive tabe fertility schedule pay more attention to the females in pop calcuate average number female offspring HUGE VARITATION in life histories as a result of tradeoffs costsbene ts or reproduction cost reproduction energy spent on offspring not spent on parent iteroparity repeated reproduction multiple reproductive periods ie squirrels this is favored in a predictable environment semeparity quotbigbang reproductionquot all reproduction concentrated in a single effort ie agave produces once a century favored in unpredictable environments low probability of adult survival tradeoffs can39t maximize all reproductive patterns at the same time meaning more offspring means smaller offspring with less care UNDERSTAND THE MODEL OF EXPONENTIAL GROWTH Population growth regulated by feedback carrying capacity number of individuals that a habitat can sustain imiting factors energy shelter nutrients territories water varies over time ogistic population growth model incorporates carrying capacity dNot rNK NK where K carrying capacity eg when N is small K NK is large characteristic Sshaped curve quotkselectionquot for traits that are helpful at high densities few relatively large offspring type I quotrseectionquot for traits that are helpful at low densities many relatively small offspring type II Population size is dynamic popuations uctuate over time result of biotic interactions there can be longterm cycles of associated populations Populations vary in space as well as time popuations connected by dispersal in a metapopulation sources positive populations growth rgt0 lots of emigration to sink sinks negative population growth rlt0 lots of immigration from sources required to maintain pop habitat fragmentation can yield a metapopulation from what originally was a large continuous population some species occur naturally in a metapopulation structure