Examining Population Density and Dispersion The following image shows a world map of human population density. Discuss with your group, the patterns that you see. Consider -Where on the map do you see the greatest population? The least population? -What “pattern of spacing” – or dispersion - do you notice? -Why do you see this type of population distribution and density?

Population Dynamics Essential concept: Each population has a a)density, b)dispersion, and a c)survival/reproductive strategy.

Examine this image below: What density, dispersion, and reproductive strategies do you notice?

Human Population Growth What are the factors that affect human population growth? World Population Watch the history of world population growth in less than seven minutes

Dynamic Population Pyramids The population pyramid is used by demographers to study the distribution of people across age categories. Why do you think this is called a population pyramid? Dynamic Population Pyramid

Understanding Exponentials Put your pens down for a minute & think about this: – An employer offers you two equal jobs for one hour each day for fourteen days. – The first pays $10 an hour. – The second pays only 1 cent per hour, but the rate doubles each hour. – Which job will you accept?

Understanding Exponentials Job 2 lags for a long time before exponential growth kicks in! Now, how much would your employer owe you if you stayed at this job for another 2 weeks? What would happen if this type of growth took place within a population?

1) Exponential growth model Also called geometric growth or J-shaped growth. First growth phase is slow and called the lag phase Second growth phase is rapid and called the exponential growth phase Bacteria can grow at this rate, so why aren’t we up to our ears in bacterial cells? Population Growth Models

Limits to exponential growth – As population density increases, competition follows as nutrients and resources are used up – The limit to population size that a particular environment can support is called carrying capacity (k) – When you’re done writing, put your pens down… Population Growth Models (cont.)

What population do you think this is?