Hi Wordwind

Sorry for a second response so quickly, but thought I needed to address the issue you have raised. You say:

If you look at all those so-called species of bats, they just look like bats the way dogs look like dogs.

It is precisely because of this layperson's view of species that taxonomists have developed more and more refined methods of distinguishing between species (or call them isolated population groups if you wish). That you or I should see a bat and think "just another bat, what's the difference" is irrelevant to the fact of whether or not bats are speciose. We are sensitised to perceive small difference in those phenomena that most directly affect us: other people (our facial recognition systems are remarkably subtle and powerful), pets, domesticated animals, garden plants and so on. Bats, on the other hand, which most of us tend not to live in close proximity to, suffer from the 'they all look the same' fallacy. As might, for instance, various species of termite, or ant.

Cladistics is the most recent, and to some minds, most successful ever method for taxonomic classification. It was devised by the entomologist Willi Hennig in the 1950s. I cannot go into the details of how it works, but read any decent book on evolution (or try the wonderful The variety of life by Colin Tudge), to see its methods and the differences between 'primitive' and 'derived' features (synapomorphies and simplesiomorphies) and so on. If you do get into it, I'm sure you'll find it fascinating. What is worth mentioning, though, is that our intuitions, or common sense, get less and less reliable the further we go from the familiar, and therefore it's not surprising that to most of us, one bat seems pretty much like another.

It makes a huge difference to the various species of bat though. I picture a baby vampire bat suckling at its mother's breast, being homeschooled, and asking her: "Mum, it's all very well to talk about spider monkeys and human beings and the like, but surely a primate is a primate is a primate. They all taste the same..."

cheer

the sunshine warrior