An ecosystem is a community of plants, animals and smaller organisms that live, feed, reproduce and interact in the same area or environment. Some ecosystems are very large. For example, many bird species nest in one place and feed in a completely different area. On the other hand, some ecosystems may be physically small, such as you would find in a meadow at the edge of a forest, or in a coral reef in the ocean. How does everything fit together in a forest ecosystem versus a meadow ecosystem? While some species may be found naturally in both areas, the species that live in the forest ecosystem are usually very different from those that inhabit the meadow, even though the two environments are right next to each other. In other words, if we protect existing natural habitats, we will help to maintain biodiversity (biodiversity is the variety of life in all its forms, levels and combinations). Unfortunately, natural habitats and their ecosystems are more and more endangered because of the damaging environmental effects of growing human populations everywhere.