This site from Palomar College provides a good background on exactly what Mendel did. Vocabulary links throughout make this a very good introduction article for genetics.

This is a great lesson plan that combines Karoytypes and evolution. Students will recognize that the chromosomes of chimpanzees and humans are remarkably similar, then correlate that to their evolutionary relationship.

Discover what evolution is through a case study of a Hawaiian snail species' survival. [7:20]

How natural selection works at the level of genes, alleles, genotypes, & phenotypes.