ECOSYSTEMS AND ECOLOGY
- An ecosystem is the resulting habitat of all the relationships among the living and non-living parts of a particular environment.
- An ecosystem with a large biodiversity will contain many types of organisms.
- In a healthy ecosystem, each organism fills a niche, i.e., each has a certain place and role in the ecosystem. For example, owls live in wooded areas and eat rodents, worms live in the soil and digest its nutrients while keeping it loose for the growth of plants, and trees provide cover for all of these.
- In a healthy ecosystem, resources remain properly distributed and competition among the organisms is at a level that does not decrease too many of their resources too quickly. But, competition for a niche may increase if a new organism enters an ecosystem and encroaches on the space and food already used by an existing species. In that case, there may be a loser as one of the competitors experiences a population decrease or perhaps even a local extinction.
- Human activity often allow species to come in contact that would otherwise hardly impact one another. Think of the rabbits introduced to Australia. With no natural predators, their numbers exploded. Native grass eaters suffered as the rabbits ate large percentages of their food plants.
- Another example is the development and accidental release of experimental Africanized bees in Brazil in the 1950's. As they spread northward, they pushed out or took over colonies of native bees.
- On a personal level, just about any time we enter some new area, we may be unknowingly importing some organism with us that remains there when we return home. What is the effect of this? Sometimes, nothing obvious but we must be aware of our potential to upset ecosystems.
- Non-living things like sunlight, temperature, and wind levels are abiotic elements of the ecosystem.
- The biotic elements of the ecosystem are all its living things.
- Carnivores are organisms that et primarily flesh (meat); usually animals.
- Animals that feed on plants are herbivores, those that feed on other animals are carnivores and animals in the chain that can feed on both plants and animals and are called omnivores.
- A general term for an animal is heterotroph because it can not make its own food as can a plant which is an autotroph.
- One indicator of the overall health of an ecosystem is the health of its indicator species. An indicator species is an organism whose health reflects the state of balance among the other components in that environment.
- Some researchers use a common amphibian, the frog, as an indicator species. Frogs and other amphibians can be found in a wide variety of environments from warm swamps to city parks to mountainous terrain. Their body structure allows them to live in the ecotone (zone) where terrestrial and aquatic environments meet. As tadpoles they are part of an aquatic food chain; as adults they fit into a terrestrial food chain. Because they are part of two worlds and part of two food chains, frogs are especially useful as living measuring sticks of the health of their environments.
The Jungle Venomous Toad,
- Tropical Ecosystems