There are two books recommended. You will not be tested on the contents of these explicitly in the exam for this part of the course, but it will be a good idea if you plan to have them read sometime during your first year:

Aitchison, Jean. (1996). The Seeds of Speech. Language Origin and Evolution. Cambridge: Cambridge University Press.

Crystal, David. (2002). The English Language. A Guided Tour of the Language. London: Penguin.

In addition, as a very nice easy way into some of the interesting questions and problems that are dealt with in linguistics, see the recent GeoWissen issue (number 40), which is all about, you guessed it, linguistics and language!