The thesis statement is a summary of?

The entire piece.

What is the point of the paper, (or thesis)?

Well if this paper is about the effect of oil spills on eco systems then your thesis statement (respectively) might look something like this.

"Oil spills have a negative effect on eco systems as this recent study shows blah blah, animals living in those zones (often already endangered) are no longer able to reproduce."

(Note: I have no idea if that is a true fact or not it is just an example)