Ecology: Organisms and Environments
Ecology encompasses the study of interactions among organisms and their biophysical environment, which includes both biotic and abiotic components.
1. Population Dynamics
Populations change in size and structure over time based on birth rates, death rates, immigration, and emigration.
2. Ecosystem Energy Flow
Energy enters ecosystems primarily through photosynthesis and is transferred through trophic levels, with an approximate 10% ecological efficiency.
| Trophic Level | Organism Type | Energy Available (Relative) |
|---|---|---|
| Primary Producers | Plants, Algae | 100% |
| Primary Consumers | Herbivores | ~10% |
| Secondary Consumers | Carnivores | ~1% |
| Tertiary Consumers | Apex Predators | ~0.1% |
Common Mistakes
Confusing Habitat and Niche: A habitat is where an organism lives; a niche is its functional role in the ecosystem (how it acquires resources and interacts with other species).