- The organisms of an ecosystem have various kinds of relationships with each other.
- In a predator-prey relationship a species gains food at the expense of the other species.
- Competition between species is harmful for both species.
- Symbiosis is a kind of mutually beneficial relationship between two species.
- An ecological niche is comprised of the resources (or needs) used by a species.
- A producer brings energy into its community through photosynthesis.
- A consumer gains energy by eating producers or other consumers.
- A decomposer gains energy by decomposing dead producers or consumers.
- Plants require nutrients in order to grow. Nitrogen and phosphorous are the two most important nutrients for many plants.