Here a bunch of link that seem useful, although they deal with different sub-fields of science:
http://home.comcast.net/~jerrypapers/whysci.html
http://www.jerf.org/iri/2005/03/04.html
http://www.intuitor.com/physics/
http://www.santarosa.edu/lifesciences/whybio.htm
http://www.cofc.edu/~chem/hbook/whystudy.html
http://www.lhup.edu/~dsimanek/chapman.htm
Also, what province do you live? In Canada and the US, IIRC, the education system is a provincial/state matter. In Quebec, you enter high school at grade 7 (you leave at 11), where you take Ecology. Afterwards, a student takes Physical Science 216 and Biology in Grade 8 and 9, respectively. You go into the either Physical Science 416 or 430, depending your math course. There are no required science course afterwards, and Physics and Chemistry are open only to those who have taken P.S. 430. In order to enter the science CEGEP (junior college - required for university admission) programs, you must have the Physics and Chemistry.