| A | B |
| primary succession | succession for the first time |
| secondary succession | succession where there were populations previously |
| pioneer species | the first plants that grow in an area |
| population | a group of individuals from a species that live in a habitat |
| growth rate | the change in the number of a population |
| birthrate | the number of births in a population in a time period |
| death rate | the number of deaths in a population in a time period |
| population density | the number of individuals in a certain amount of area |
| dispersion | how the individuals are arranged in a space |
| random dispersion | type of dispersion where there is no pattern |
| even dispersion | type of dispersion where individuals are spaced evenly |
| clumped dispersion | type of dispersion where individuals are in clusters |
| immigration | individuals move INTO a population |
| emigration | individuals move OUT of a population |
| demography | the scientific study of human populations |
| r-strategists | species that reproduce quickly and in large numbers |
| K-strategists | species that reproduce slowly and in low numbers |
| age structure | the number of males and females of each age in the population |