Tuesday October 20th In Notebook: Write 3 sentences about who is eating who in this forest food web. & Label the autotrophs and heterotrophs. Todays Learning Targets Agenda: 1.Go over test & Ecology Plan of Action 2.Learning Targets - Ecology Part 2 3.Population Notes 4.Practice Worksheet - Due Thursday What do we study about populations? The organisms dispersion and density The range of their habitat that they utilize HOW and WHY the population size changes Long term sustainability of populations 3 types of dispersion*: *dispersion = pattern of spacing Predicated Name: (TPS) Actual Name: Density = # of organisms per area Limiting Factors = anything that limits the population size. Can be: conditions TemperatureHumidity RainfallSunlight conditions Predators Competitors parasites Density Independent Factors Density Dependent Factors Density Independent Factors affects the size of a population regardless of the population density Abiotic Weather, Water, Fire, Sunlight, temperature Humans dams, pollution Density Dependent Factors A factor whose effects on the size or growth of population vary with the population density Biotic factors Predation, disease/parasites, competition Food, water, shelter (resources) Population Range Tolerance ability of an organism to survive when subjected to limiting factors Upper and lower limit = range How does a population size change? Birth and Death Rate Birth Rate = Death Rate Birth Rate > Death Rate Immigration and Emigration - Immigration = moving into a population - Emigration = moving out of a population Immigration = Emigration Immigration > Emigration Change over time = a rate! Growth rate = (end population - starting population) starting population 2 types of Growth Rates Exponential Occurs only under ideal conditions Why is this rarely seen in nature? Logistic Population goes through several growth stages Lag Exponential Slows Steady state ? Carrying Capacity = Maximum number of individuals that an environment can support