| A | B |
|---|
 | A cheetah - natural selection favors organisms that live to reproduce successfully |
 | Cryptic coloration |
 | Hydroelectric power - Potential or stored energy |
 | Fragmentation - Cutting intact habitat into smaller pieces |
 | Competition between different predators - a negative effect on all species involved |
 | The second law of thermodynamics - When energy changes forms, some is lost as heat |
 | Commensalism - A positive effect on one species, the other species remains unaffected |
 | The rivet hypothesis |
 | Root nodules - Nitrogen must be fixed to be usable to most living things |
 | Ecological succession |
