400 word answer with reference

How does energy flow through an ecosystem? What is a producer, a consumer (primary and secondary) and a decomposer?
How is the human body similar to an ecosystem? Provide a description of two ways in which the human body is similar to an ecosystem.
Select two of the organ systems in the human body and describe their function. What role(s) do they play in maintaining the environment of the human body?
Humans are consumers in the ecosystem. As part of our evolution, we have developed and urbanized many parts of the world affecting the habitat of other species. Select a city or town in the United States that has become urbanized and postulate or provide a supported example of how another species have adapted to the urban environment.
Do you think that humans should make a greater effort to protect the habitats of other species? What efforts do you recommend?