Population ecology is the study of how populations — of plants, animals, and other organisms — change over time and space and interact with their environment. Populations are groups of ...

But is growth of the human population responsible for the environmental catastrophe our planet is facing? The data tell a different story. For example, although high-income and upper-middle-income ...

You can pin an age by clicking on it: for example, you can see how the group of 5-year-olds in 1950 changes through the years. Move the mouse over the pyramid to see how many men and women each age ...

The founder effect is an extreme example of "genetic drift." Genes occurring at a certain frequency in the larger population will occur at a different frequency -- more or less often -- in a ...