Population Growth Patterns

Population Size Population size is the number of individuals that make up a population. Immigration and births increase population size. Emigration and deaths decrease population size.The table below shows how several different populations have changed over a one-year time span. Look at each population and determine whether the overall population size has increased or decreased. Population Births (+) Deaths (-) Number of individuals that Emigrated (-) Number of individuals that Immigrated (+) Population size A 200 100 0 0 increased B 10 10 100 0 decreased C 1 1 1 50 increased D 10 100 100 10 decreased A food shortage causes many members of a population to leave an area. This type of population movement is called Emigration. An abundance (lots of or plenty) of food causes many members of a population to enter an area. This type of population movement is called Immigration. What must occur in a population for it to grow? The birth rate stays the same and the death rate increases. The birth rate becomes lower than the death rate. The birthrate and the death rate remain the same. The birth rate becomes higher than the death rate. Population Density is the number of individuals in a population in a unit area. A small farming community in Texas covers 14 square kilometers. There are 420 individuals who live within the town limits. What is the population density of this community? (show the math) Hint: Number of individual area = Density420 = 30 There are 150 Saguaro cactus plants per square kilometer in a certain area of Arizona desert. To which population characteristic does this information refer? growth rate population density age structure geographic distribution Which of the following tells you population density? the number of births per year the number of frogs in a pond the number of deaths per year the number of bacteria per square millimeter Patterns of population growth: Exponential and Logistic Growth Curves Exponential growth occurs when individuals in a population are reproducing at a constant rate under an ideal condition.Logistic growth occurs when a population’s growth slows or stops after a period when they reach the carrying capacity. Give each graph (below) a title based on the type of population growth it depicts. Then label the Carrying capacity. Use the following words for labeling:Logistic Growth CurveExponential Growth CurveCarrying Capacity Exponential Growth Curve Carrying Capacity Logistic Growth Curve Use the two graphs above to answer the questions below. 1. Which graph shows a population that has reached its carrying capacity? Graph II2. Which graph represents a population that is growing under ideal conditions with unlimited resources? Graph I What is carrying capacity? Use the graph below to answer the following questions. 1. Which time period (B or C or D) shows exponential growth of the population? B2. During which time period (B or C or D) are the birth rate and death rate equal? CThe time period (B or C or D) during which the rate of growth would have a negative value is D. Define limiting factor. Density Dependent Limiting Factors Disease parasitism predation food water mates shelter Density Independent Limiting Factors Climate change Human Activity tornado hurricane volcanic eruption flood earthquakes VERY cold winter VERY hot summer