| free-living | |
| —adj | |
| 1. | given to ready indulgence of the appetites |
| 2. | (of animals and plants) not parasitic; existing independently |
| free-'liver | |
| —n | |
| variation in traits such as body weight or height in which a series of types are distributed on a continuum, not grouped into discrete categories |
| natural selection that favors altruistic behavior toward close relatives resulting in an increase in the individual's genetic contribution to the gene pool |