Chapter 53: Population Ecology
Chapter 53: Population Ecology BYS 120
Popular in Organismal Biology
Popular in Biological Sciences
This 0 page Class Notes was uploaded by Amelia Notetaker on Tuesday December 8, 2015. The Class Notes belongs to BYS 120 at University of Alabama - Huntsville taught by Dr. Luciano Matzkin in Fall 2015. Since its upload, it has received 30 views. For similar materials see Organismal Biology in Biological Sciences at University of Alabama - Huntsville.
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Date Created: 12/08/15
Chapter 53 Lecture Notes Distribution of species 0 Both biotic and abiotic factors can help distribution of species o Biotic Predation Herbivory Pathogens Competition Abiotic Temperature 0 Water availability 0 Oxygen availability Salinity Suanht Soil composition Population characteristics 0 Density is number of individual per unit area or volume Dens y O O 0 Sampling techniques can be used to estimate densities and total population size Estimate population size by Extrapolation from small samples 0 Index of population size Markrecapture method Result of interplay between processes that add individuals to a population and those in it Births and immigration adds to population Deaths and emigration subtracts to population Population characteristics 0 Individuals within boundaries of the population Clumped dispersion 0 Individuals aggregate in patches 0 May be in uences by resource availability and behavior Uniform dispersion o lndividual39s evenly distributed 0 In uenced by social interactions Random dispersion 0 Position of each individual is independent among other factors Demographics 0 Study of vital stats of a population and how the change over time 0 Death rates and birth rates are of particular interest Survivorship curves 0 Type one low death rates during early and middle life and increase among older age groups 0 Type 2 constant death rate over life span 0 Type 3 high death rates for the young and low death rates for the survivors Population growth 0 Population39s change in size is Births emigrations deaths immigration Delta Ndelta t gt births death bd o Births and deaths can be expressed as the average number of births and deaths per individual during speci ed time interval B gt annual capita birth rate BbN DmN M annual per capita mortality rate N population size 0 Delta Ndetla t bNmN gt bmN o Instantaneous growth rate can be expressed as dNdt rinstant N o Describes exponential growth 0 Population rises under idealized conditions Problems with exponential growth 0 Can39t be sustained for long in any population 0 More realistic population model limits growth by incorporating carrying capac y Carrying capacity k actual ax population size the environment can support Varies with abundance of limited resources Logistic population growth model 0 Per capita rate of bigger population declines as carrying capacity is reached 0 Delta Ndelta t rmax NkNK 0 Some populations overshoot k before setting down relatively stable dens y 0 Some populations uctuate and make it dif cult to nd k Life history traits o Comprises the traits that affect its reproduction and survival Age reproduction begins How often organisms reproduce How many offspring produced during each reproductive cycle 0 Observed in developmental psychology and behavior of an organism 0 Species that exhibits semelparity reproduce once and die 0 Species that exhibit interparity produce offspring repeatedly Assuming an animal is semelparous what environment would it live in 0 Highly unpredictable levels of resources from year to year Life history trade offs o Organisms have nite resources which may lead to tradeoffs between survival and reproduction Types of selection 0 K selection density dependent selection selects like of history traits that are sensitive to population density o R selection density independent selection selects for life history traits that maximizes reproduction Population growth regulations 0 Density dependent populations39 birth rates and death rates don39t change population density Negative feedback loop 0 DD birth and death rates are an example of negative feedback that regulates population growth 0 Factors affecting birth and death rates 0 DD birth and death rates are affected by Competition for resources Territory gt nesting sites Disease Predation Toxic wastes Population dynamics 0 Sometime populations aren39t stable overtime but uctuate 0 Complex interactions between biotic and abiotic factors affect population dynamics