How many species 3: an answer, and some more questions.

In a previous post, I presented an example of one of the questions that evolutionary biologists face. In this example, I described three populations of closely related insects, presented a few details about their distribution, and gave the results for some laboratory-based breeding studies that were conducted with these populations some years back. I then asked people to guess how many species the three populations were divided into by scientists. Their answers, and some questions, can be found in comment threads both at The Panda’s Thumb and at The Questionable Authority.

If you look at the answers that people have given, you will see that all three possible choices (1 species, 2 species, and 3 species) have received some votes. The most popular answer is that there are 2 species, with populations A and B being put together as a single species, and population C being given status as a separate species. The people who have chosen this option focused on the obvious differences in fertility for the crosses involving population C. The person who voted for three species did so based on the high likelihood that all three populations are on separate evolutionary tracks. The people who voted for a single species did so based on the fact that, despite the male sterility, population C is still interfertile with populations A and B. Several people also asked for more information. I’ll try to satisfy some of those requests in this post.

Read More (at The Questionable Authority):