April 17, 2012 List four biogeochemical processes that cycle nutrients. Explain the difference between primary and secondary succession. Give an example of primary and secondary succession which can be found in our area.

Populations SPI 3210.2.2 SPI 3210.2.3 SPI 3210.Math.1 SPI 3210.Inq.3

Essential Question: What factors contribute to population growth or decline?

What’s different about these two population areas? Times Square, New York City Mumbai, India

Let’s Think About This… Population of India 1,170,938,000 (2010) Population of United States 307,006,550 (2009)

Characteristics of Populations Three important characteristics of a population are: Dispersion: pattern of spacing of a population (uniform, random, clumped) Population density: number of individuals per unit area Growth rate: number of births, deaths, and number of immigrants/emigrants.

Population Growth Exponential Growth Occurs when individuals in a population reproduce at a constant rate. This will occur under ideal conditions with unlimited resources

Exponential Growth

Population Growth Logistic Growth Most populations will grow exponentially at first, but eventually growth slows down as resources become less available. Carrying capacity: The largest number of organisms a given environment can support.

Logistic Growth

April 18, 2012 List three characteristics that are used to describe a population. What is the difference between exponential growth and logistic growth? Does exponential growth have a carrying capacity? Explain your answer.

Limits to Population Growth Limiting Factors: Causes population growth to slow down or decrease Density-dependent Density-independent

Density-Dependent Factors Become limiting only when the population density reaches a certain level. These factors will not affect small, scattered populations. Competition, predation, parasitism, and disease

Density-Independent Factors Affect all populations in similar ways, regardless of the size. These factors include unusual weather, natural disasters, seasonal cycles, and human activities.

Which of the following would be considered a density-dependent factor? Deforestation Hurricane Flooding Predation

Which of the following would be considered a density-independent factor? Competition Parasitism Forest fire Contagious disease