Classification of Animals
Traditional classification: 35 phyla
Based on anatomy and embryology
Hierarchy of characteristics used in phylogeny:
- tissues
- symmetry
- body cavities (coelom)
- embryology (origin of mouth and anus in early embryo)
- Segmentation
Tissues: divides animals in Parazoa and Eumetazoa
Parazoa do not possess distinct tissues and lack symmetry: Porifera = sponges