population ecolog notes
population ecolog notes BIOL 201 A02
Popular in Prin of Ecology & Evolution
Popular in Natural Sciences and Mathematics
This 5 page Class Notes was uploaded by Elise Pinter on Monday September 14, 2015. The Class Notes belongs to BIOL 201 A02 at Indiana University of Pennsylvania taught by D Janetski in Fall 2015. Since its upload, it has received 22 views. For similar materials see Prin of Ecology & Evolution in Natural Sciences and Mathematics at Indiana University of Pennsylvania.
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Date Created: 09/14/15
Chapter 53 Population Ecology 393 Population VVVVVVV VV gt Group of individuals of a single species Live in the same general area Generally use the same resources In uenced by similar environmental factors Likely to interact and breed with one another BUT often times arbitrarily de nes by an investigator Population ecology explores how biotic and abiotic factors in uence the density distribution size and age structure of populations focuses on one species Dispersal how does this affect how you de ne population Abundance total number of individuals or biomass of a species in a speci ed area Densitynumber of individuals per unit area Small body organisms are found in higher densities that large body organisms Dispersionspatial pattern of individuals Different from dispersal which is when organisms move from place to place Types Clumped o Organisms are more likely to be found closer to each other 9 Most common o More effective for hunting and protection o Clumping due to lack of dispersal or vegetative reproduction clumping due to patchy resources or environmental conditions 9 Humans have clumped population 0 Uniform o Organisms are evenly dispersed throughout the landscape 9 Competing for space and resources 0 Random o Location of a particular individual has no impact on the location of another c There are statistical techniques to determine spatial patterns gt Make a quadrat and plot Cartesian coordinates on a map xy Markrecapture method Think in terms of ratios sNxn o 5 number marked in rst sampling 9 Nestimated population size o X number marked observed in 2nCI sampling Chapter 53 Population Ecology 9 n total number captured in 2ncl sampling assumptions marked and unmarked individuals have same probability of capture marked individuals have mixed completely back into the populations by 2nOI sampling 0 no birth death immigration or emigration between rst and second sampling gt Demographics study of vital statistics of populations and how they change over time 0 Birth rate natality Death rate mortality Life table summary of age speci c vital statistics of a population gt Survivorship curve Type 1 low mortality early in life few off spring good parental care Type 2 mortality unrelated to age intermediate number of offspring Type 3 high mortality rate early in life many offspring little or no parental care gt Population attributes Growth rate change in population size over time 0 AN AT 9 A change in o N population size 9 T time Growth rate change in population size closed population 0 AN lAT B D o A change in o N population size 9 T time o B births natality o D deaths mortality Growth rate change in population size open population ANATB DlE 9 Delta change in N population size T time B births natality D deaths mortality l immigration E emigration Per capita rate of increase r o r b m 000 Chapter 53 Population Ecology o b per capita birth rate 9 m per capita death rate change in population size 0 ANAt rN Instantaneous or intrinsic per capita rate of increase rinst rinstN gt Exponential Growth 39 rinstN Exponential population growth occurs when rinstgt 0 and is constant at each instant in time As N increases the population size increases more and more quickly Resources andor density do not limit growth All members of the population are free to reproduce at their full biological capacity birth and death rate aredensity independent Exponential growth has a Jshaped curve Exponential growth is often followed by a crash in the population when resources run out gt Logistic Growth Per capita rate of increase r approaches zero as N nears the carrying capacity K Creates Sshaped curve Resources andor density limit growth Birth and death rate are density dependent When N is low growth rate is near exponential When N K growth rate is zero dN dt rN K NK o exponential growth equation plus K NK where K carrying capacity or maximum population size sustainable by a given environment gt other considerations densitydependent mortality and natality can produce a variety of patters in population growth sometimes a population may overshoot its carrying capacity 0 Allee effect individual tness is correlated with population size or dens y 9 Survival reduced at low population sizes gt Survival reduced at low population sizes Extinction vortex small populations are prone to extinction gt Life history Chapter 53 Population Ecology Traits the affect an organism s schedule of reproduction and survival make up its life history Related to development physiology and behavior gt Life history traits Size at birth Growth pattern Age and size at maturity Number size and sex ratio of offspring Age and size speci c reproductive effort Length of life gt Principle of Allocation Total energy maintenance growth reproduction Tradeoffs reduced survival or reduced future reproduction because of current reproduction gt Semelparity Reproduce once in a lifetime 0 Annual plants like ragweed Salmon 0 Agave gt lteroparity Reproduce more than once in a lifetime Perennial plants like goldenrods or trees 0 Many animals gt Reproductive strategies rselection many offspring little parental investment density independent selection Maximizes reproductive success in uncrowded environments K selection few offspring large parental investment density dependent selection Selection for traits that are sensitive to population density and are favored at high densities gt Population regulation When a population oscillates around a particular equilibrium size gt Factors that can result in densitydependent mortality or natality Competition for resources Territoriality competition for space gannets Disease transmission is faster and easier in crowded conditions Predators can eat more prey when prey are abundant Accumulation of waste Intrinsic factors hormonal changes in mice with high density gt Population dynamics uctuations in population size from year to year or place to place Metapopulation many local populations linked by immigrants amp emigration Chapter 53 Population Ecology Demographic transition shift from high birth and death rates at low birth and death rates Ecological footprint aggregate land and water area required by each person city or nation to produce all the resources it consumes Opportunistic species take advantage of good resource availability gt rselection opportunistic small individuals usually short life span fast to mature many offspring little or no parental care many offspring die before reproducing early reproductive age gt K selection Large individuals Long life span Slow to mature Few and large offspring Parental care Most young survive to reproductive age Adapted to stable environment
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