Question

How is a habitat different from an ecosystem?

Answer 1

With a habitat, you are generally referring to one specific population and the area it inhabits, for example you would say sharks live in aquatic habitats. An ecosystem refers to a specific environment and all the organisms that live in it, for example you might say that a particular pond has an ecosystem that includes several organsims.

They can overlap, but they are different.

http://en.wikipedia.org/wiki/Habitat
http://en.wikipedia.org/wiki/Ecosystem