Trends in Animal Evolution

Possible ancestral organism - choanoflagellates Fig 32.2

One hypothesis for origin of animals - Fig 32.3

Characteristics of animals

Traditional phylogeny of animals - Fig 32.4 - Animal phylogeny based on r-RNA sequencing - Fig 32.8

Comparison molecular VS body plans phylogenies Fig 32.12     Table of animal phyla - Table 33.7.

Symmetry - Fig. 32.5
Radial symmetry
Oral
Aboral
Bilateral symmetry
Dorsal
Ventral
Anterior
Posterior
Cephalization

The Parazoa - no true tissues

Phylum Porifera: The Sponges - Fig 33.2 and Fig 33.3

The Eumetazoa - true tissues develop from germ layers

DIPLOBLASTIC (2 cell layers - Fig 40.7b) EUMETAZOA - THE RADIATA

Phylum Cnidaria: The Cnidarians - Fig 33.6 and Table 33.1

Polyp vs. medusa - Fig 33.4; swimming jellyfish, a medusa.
Cnidocytes - Fig 33.5
Digestion - Fig 41.11: Hydra eating water flea!

TRIPLOBLASTIC EUMETAZOA - THE BILATERIA

Body Plans of Triploblastic Bilaterally Symmetrical Animals - Fig 32.6

Acoelomate
Pseudocoelomate
Coelomate

Protostomia vs. Deuterostomia - Fig 32.7 - cleavage patterns and coelom formation

Protostomia - divided into Lophotrochozoa and Ecdysozoa

Lophotrochozoa (Lopho + trocho) Lophophorate - Fig 32.11 and Fig 33.14. A trochophore larva - Fig 32.9

Phylum Platyhelminthes: The Flatworms - Table 33.2

Acoelomate animals - no body cavity
Planarians - Fig. 33.10
Flukes - Schistosoma blood flukes. Life cycle - Fig 33.11
Tapeworms - Fig 33.12

Phylum Mollusca: The Mollusks Basic Body Plan - Coelomate animals - Fig 33.16 - Table 33.3 (snails, slugs - Fig 33.19); nudibranch, the movie! (bivalves - Fig 33.20; clams - internal anatomy - Coelomate animals - Fig 33.21) (octopuses, squids - Fig 33.22).

Phylum Annelida: The Annelids: Segmented worms -Fig 33.24 and Table 33.4 - earthworms - internal anatomy - Fig 33.23, leeches, polychaetes

Ecdysozoa - ecdysis - shedding of exoskeleton - Fig 32.10

Phylum Nematoda: Nematodes Fig 33.25a and roundworms. Fig 33.25b - parasitic Trichinella

        Pseudocoelomate animals: a false coelom (body cavity)

Phylum Arthropoda (Jointed-foot animals)

Coelomate animals with exoskeletons

- Table 33.5 - Crustaceans (Fig 33.35) like lobsters (external anatomy - Fig 33.26) Lobster mouthparts in action! crabs, shrimp. Trilobites (Fig 33.27). Horseshoe crabs (Fig 33.28). Arachnids like spiders (Fig 33.30 and Fig 33.30b), scorpions and internal mites (Fig 33.29). Millepedes (Fig 33.31a). Insects will be covered in the next lecture.

Deuterostomia - Coelomate animals

Phylum Echinodermata: (Fig 33.37) The echinoderms - starfish (Fig 33.38), sea cucumbers, sea urchins. Tube feet - the movie!

Phylum Chordata: non-vertebrate and vertebrate chordates. Covered in another lecture.