1. Population Ecology Population - group of individuals of the same species living in the same general area. – They must rely on the same resources, have a good chance of interacting with each other, and have the similar environmental factors.

2. Factors affecting populations – Dispersion - how they are spread throughout their boundary area clumped (most common) - maximizes reproduction uniform (evenly spread) - maximizes survival in there are limited resources – territoriality

3. Factors affecting populations – Density - # of individuals per unit area counting & estimation dynamic due to immigration, emigration, births & deaths Demography - study of the vital statistics of populations and how they change over time – Reproductive rates - ignores males of a species – Immigration vs emigration

4. Growth exponential model – Represents a species with unlimited resources and space Assumes NO competition – cannot sustain itself due to the resources available. (example: a single E. coli reproducing every 20 minutes would cover the world in less than 36hours) 1 -2-4-16-256-65536-4294967296... (4billion in 2 ½ hours!!!)

5. Growth Logistic Growth – most growth goes through stable and fluctuating periods – although the number of humans are still increasing the rate of growth slows each year as we lose members to disease and choice population dynamics is the study of biotic and abiotic factors that influence population size – Carrying capacity - the amount of individuals that can be supported in one system it is estimated that the carrying capacity for humans is 10-15 billion (a number to be reached by 2050 if there is not some global catastrophe) can be further estimated by looking at the ecological footprint - the area a population needs to gather resources and dispose of its waste the US needs 8.4 ha/person but only has 6.2ha/person - over carrying capacity