 I can describe the key characteristics of populations.  I can describe the different types of population growth.  I can differentiate between Density dependent factors and Density Independent factors.  I can explain a Life Survivorship Curve.  Homework: Read “Winter Plants” in The Forest Unseen

 Characteristics of Populations: Three important characteristics of a population are its geographic distribution, density and growth rate.  Population density is the number of individuals in an area.  Population Growth is the number of births, the number of deaths and the number of individuals entering or leaving the population.  Geographic Distribution is how the organisms are arranged (distributed) on earth (not just where they are found).

 Key Terms to know: Logistic growth – when the population growth slows or stops Carrying capacity – the limit of individuals that the environment can sustain. Exponential growth – when the individuals are reproducing at a constant rate.

 A Survivorship Curve is a plot of the proportion of numbers in a group alive at a given age.

 Clumped; many organisms are clumped do to resource supply.  Uniformed; many organisms are uniformly dispersed due to territories.  Random; many organisms are found in random due seed dispersal.

 Density Dependent Factors: these limit the population when the density becomes too great.  Density dependent factors include competition, predation, parasitism and disease  Density Independent Factors: limit the population regardless of the population size.  Examples include damming rivers, natural disasters, clear cutting forests, seasonal cycles, etc.

 Turn to page 123 in your text book.  Answer the question do fruit flies and rabbits show similar trends in population growth?