I've brought two boxes full of beetles that belong to Dr. Gier. We'll look at the beetles and talk about what a species is and how scientists come up with different names for different species. For those of you who prefer plants to beetles, I've also put some photos together of some different plant species in the genus Pedicularis. Look at the photos and think about the difference between the flowers. The following information is presented in a slightly different way than it is presented in your text.
Allopatric speciation takes place when two populations are geographically isolated.
The figure 14.1 shows a way in which allopatric speciation might happen. This form of speciation can happen with all life forms. Sympatric speciation occurs within a population, without geographic isolation. This may be common among some insects and animal parasites. Polyploid individuals in a population are often unable to interbreed with normal individuals, and so even though there is no geographic barrier to genetic interchange, there is a biological one.