 The number of individuals in a specific area  The equation for population density is: number of individuals Pop. density= unit area

 Suppose you counted 20 monarch butterflies in a garden measuring 10 square meters  The population density would be 20 monarchs per 10 square meters, or 2 monarchs per square meter

IIn the pond on the right there are 6 flamingos in a 120 square foot area.  What is the population density of the flamingos in this pond? 1120/6 =.05 flamingos per square foot! 12 ft. 10 ft.

 Drought  Lack of food  Lack of shelter  Natural disaster (earthquake, tsunami, hurricane)  Disease  Over hunting

 An environmental factor that can cause a population to decrease  All of the things we just saw that affect a populations size are limiting factors. - a lack of food, water shelter, space, etc…

 The largest population that an area can support  What do you think happens when an ecosystem reaches its carrying capacity of a certain species?  Some of that species will have to die

 A positive condition that occurs when all the organisms in an ecosystem has their needs met  Think of it as a see saw. If the ecosystem is balanced the population will go up and then back down This is balanced! This is not balanced!