BIOL 1010U Lecture Notes - Lecture 4: Myriapoda, Chitin, Ecdysis
Document Summary
Textbook reference: chapter 44 in biology how life works (2nd ed. ) Based on: embryo formation and molecular sequence data. Bilaterians form two major groups: protostomes, deuterostomia. Complex organs that develop from a tiploblastic (three germ layer) embryo. Anatomical complexity of bilaterian animals allows for types of locomotion, feeding, gas exchange, behaviour, and reproduction unknown in earlier branching groups. Protostome animals can be further divided into two groups (based on molecular sequence data): lophotrochozoa, ecdysozoa. Mostly small marine animals of limited diversity. Also includes the diverse and ecologically important: Name comes from two morphological features found in some of its members: Lophophore ciliated crown of tentacles used for feeding. Trochophore larva have a tuft of cilia on top and additional cilia bands around middle. Some members of group have neither of these characteristics. Fine branches of gastrovascular cavity distribute food directly to cells. Some live as parasites in or on other animals.
