Nature... help!

Apropos of Z's recent post I've decided to teach a freshman seminar on appeals to human nature in ethics/bioethics this spring. I basically have no idea what will be on the syllabus, except for stuff from the Nicomachaen Ethics. I'd also like to read Nagel's "Sexual Perversion", for kicks. Chapter 1 from Foot's "Natural Goodness" as well. Look at some cloning/enhancement debates from bioethics. 'Emotion' is in the title of my seminar, too, but there's just about no literature on emotion that I like, unfortunately.

Any ideas? Anything from Hume, Locke, Hobbes, Hutcheson, Moore, Sidgwick that freshmen should read? Oh yes, this is supposed to be a cross-disciplinary sort of course, so are there any sociobiological/evolutionary psychological/ethical naturalist-types who you can recommend for such a course? Help!

(Update, here's my course description:

One of the most common objections to many biotechnological procedures is that they are unnatural. However, it is clear that no simple appeal to naturalness can tell us what is good and bad for human beings: e.g. it's natural to want to drink sea water when shipwrecked, but doing this is disastrous; the manufacture of penicillin is (in at least one sense) unnatural, but good for us. Nevertheless, what is good and bad for us clearly depends on our biological features, which is evident even in the previous two examples: drinking sea-water is bad for us, and taking penicillin sometimes good, because of our physiological nature. More generally, health is obviously an important part of a good life – and thus, of bioethics – and it seems quite unlikely that we could make sense of human health without appealing to nature in some way. (Some sample questions we might ask here: Is deafness unhealthy? Is it wrong to choose deafness for others, as some deaf parents are reportedly doing with pre-implantation genetic diagnosis?)

Thus, one central question for the course is whether we can make sense of human nature in a way that would help us answer difficult bioethical questions, particularly those surrounding reproductive technologies and genetic enhancements. However, biotechnology appears to give us the freedom to change our nature in significant ways – this is why many people are frightened by it – and this poses the other central question for the course: can we determine whether a “post-human” nature would be good? I hope to show that examining emotions such as guilt, disgust and empathy will help us answer these questions. Readings will include contemporary debates in bioethics, philosophical texts on the relation between nature and ethics, as well as attempts by biologists to "naturalize" ethics by theorizing about its evolutionary origins and functions.)