| I: | the level of biological organization, where the study is begun, is the organism. |
| II: | a group of individuals resulting from asexual reproduction is also considered a population. |
| 1. | an increase in number |
| 2. | a decrease in number |
| 3. | no change in number |
| 4. | an unpredictable change – may be an increase or may be a decrease – in number |
| I: | Natality |
| II: | Mortality |
| III: | Emigration |
| IV: | Immigration |
| I: | When resources in a habitat are unlimited, populations undergo exponential growth. |
| II: | Resources are always unlimited for plants but never for animals. |
| 1. | Mutualism | 2. | Commensalism |
| 3. | Parasitism | 4. | Competition |