Cleveland P. Hickman

So, I was in my local Goodwill and they had this in the $1 used textbook section, and I hadn’t taken a zoology course since 1975, so I figured why not? Worked my way through, doing all the end-of-chapter problems to make sure I was getting it. After sections on basic physiology, the bulk of the book is a walk through the animal kingdom (including protists) to about the class level; then some concluding chapters going into more detailed physiology (for example, how nerve impulses are transmitted). Not surprisingly, vertebrates are emphasized – author prejudice, I suppose.


Since my personal interests are mostly taxonomic, a couple of items were big news, due to the advent of molecular classification:


Myxozoans, an intercellular fish parasite, turn out to be cnidarians. When first discovered these things were thought to be protists – then somebody noticed they were multicellular (AFAIK the smallest multicellular organism known); then it was assumed they were acoelomate worms – which, AFAIK, are the only other multicellular intercellular parasites (flukes). But molecular taxonomy groups them with cnidarians. Intercellular parasitic jellyfish – who knew?


Then, on the same theme of taxonomic surprise, pentastomids (tongueworms – because they supposedly look like tongues; they’re actually respiratory parasites) turned out to be branchiurid crustaceans. It was long thought pentastomids were related to arthropods , although they were generally put in their own phylum, but not only are they arthropods, they’re crustaceans, and can actually be pinned down to the subclass level.


And for a final surprise, Hexapoda and Crustracea turn out to be sister groups. This is a real body blow to traditional phyletic taxonomy; the former big divisions among arthropods were Chelicerata versus Mandibulata, then Mandibulata was subdivided between Uniramia (Hexapod plus Myriopoda) and Crustacea. The key here was the biramous versus uniramous appendages; Crustaceans are biramous, with the appendages (even the antenna) split into two parts, one which is usually used for feeding and respiration and one for walking, while the uniramians have only one part to the appendages. This was assumed to be a primitive division; it turns out not to be. How about that?


Thus very enlightening. The book was supposed to come with a CD that had all sorts of cool zoology software – but it was missing; well, what do you want for $1? Lots of excellent illustrations, good index and glossary; just the thing for the enthusiastic amateur.… (mehr)