Resistance to parasites is likely to have some cost, i.e. the energy allocated to defense cannot be used for other purposes. Determining the genetic control of resistance is important because the coevolutionary dynamics resulting from resistance that is under the control of a few major genes may be markedly different from that resulting from the pyramiding of many resistance alleles at many loci. Most are links to better lists of links. More than just Dawkins- a great assortment of links A white paper on evolution by Douglas Futuyma and others. The Smithsonian Institute Creation vs. Evolution links .
Many people are willfully ignorant about evolution.
In addition to the following, the Dawkins page above is useful The Talk. Origins Archive Innumerable resources and links. The FAQ is a good starting point. There are no gods, no purposes, and no goal directed forces of any kind. There is no life after death.