UNDERSTANDING POPULATIONS

 Members of the same species (reproduce with one another)  Live in the same place (Geographic location)  Live at the same time (Past, Present, or Future)

 Death Rate + Birth Rate = Growth Rate  Populations usually stay about the same.  Reproductive Potential ◦ Fastest rate an organism can grow ◦ Increase when organisms reproduce more often ◦ Small organisms (bacteria) usually reproduce quicker than larger organisms (humans)

 Organisms Grow faster and faster over time!  Conditions ◦ Plenty of Food, Space, and no competition or predators

 Environment Changes  Resources are Used Up  Death Increases  Births Decrease  Carrying Capacity ◦ Maximum population that the ecosystem for a particular species can support.

 Limiting Resources such as sunlight, nutrients, water.  Carrying capacity is reached when the resource is consumed at the rate that it is made!

 Organisms compete for resources such as: ◦ Territory – Living Space ◦ Mates ◦ Food ◦ Homes/Shelter

 Density Dependent – cause of death is related to issues of overcrowding/space.  Density Independent – Not related to number of organisms but other factors such as weather, natural disasters, etc.