Ecology:

     Ecology is the study of the relationships of organisms to one another and their physical surroundings.  Abiotic factors are non living, water, air, pollen, soil, temperature, light, and natural disasters are some of the abiotic factors.  Biotic factors are living things.
Ecosystems:

     An ecosystem is a biological community of interacting organisms and their non living environment.  The Bullfrog is found in the wetland ecosystem.  Wetlands are marshes, ponds, swamps, bogs, and similar areas. Wetlands are found in flat vegetated areas.
Biomes:

     A biome is a large area, with similar organisms.  Organisms adapt to the varying conditions, water, heat, and soil.
  Animal relationships:
Animals will, help, harm, and use each other, this is called symbiosis.  Symbiosis is the relationship between animals.  Parasitism is when one organism is harmed, and one is benefited, such as a heart worm in a dog.  Commensalism is when one animal is benefited and the other is not effected.  Mutualism is when both animal are benefited, an example is a clown fish, and anemones,  The clown fish can live in the anemone because the clown fish has a substance on it that protects it from being stung, and in turn the clown fish cleans the anemones.  Competition is when two organisms need the same resource, competition usually happens with the same species, but sometimes with other species.
Limiting factors:
Limiting factors are the availability of food, water, shelter, and space.  If the population of animals in an ecosystem gets too high, some animals will not survive.  Size is also a limiting factor and will even out the population of animals as well.  Humans impact animal populations also. When humans develop land for houses and buildings, they cut down trees and change animal habitats.
Adaptations:
Animals adapt to their ecosystem.  For example, the polar bear has adapted in many ways.  Its fur protects it from the cold, its teeth help it hunt, and swims very well, so that it can fish, along with many other adaptations.  
Diversity:

An ecosystem that is healthy has a lot of species diversity.  The more species diversity, the less likely to be damaged by human interaction.  How would a food chain work without species diversity?
Bibliography:

http://library.thinkquest.org/11353/ecosystems.htm
http://www.stemnet.nf.ca/CITE/ecowetlands.htm
http://www.nhptv.org/natureworks/nwep12a.htm
Mr. Payne
Links:
Bullfrog
Foodweb