Chapter 32: Introduction to Animal Evolution Chapter 33: Invertebrates Overview of Animal Phylogeny part 1: invertebrates

Invertebrates: orientation to topics

Figure 33.1 Review of animal phylogeny

Table 25-1a

The Situation in the Late Precambrian Precambrian origin of integrated organisms and basic body plans Parazoa (Porifera) sponges Radiata (Cnidaria) sea anemones and sea pens Bilateralia Protostomes primitive molluscs unidentified worms Charnia masoni - a sea pen Dickinsonia costata - annelid?

Fossils from the End of the Precambrian…

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA colonial choanoflagellate

Figure 33.2 Sponges

Figure 33.3 Anatomy of a sponge Sponges have specialized cells, But they lack true tissues, groups of similar cells that act as a functional unit and are Isolated from other tissues by Membranous layers.

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA

Figure 33.6 Cnidarians: Hydrozoans (top left), jelly (top right), sea anemone (bottom left), coral polyps (bottom right)

Figure 33.5 A cnidocyte of a hydra

Figure 33.4bx Jelly medusa

Figure 33.4 Polyp and medusa forms of cnidarians

A cnidarian life cycle

Figure 26.8 The Cambrian radiation of animals (Ediacaran) 525 Burgess Shale PL PE D D R P

Figure 32.13x Burgess Shale fossils

Figure A sample of some of the animals that evolved during the Cambrian explosion

Porifera and Cnidaria are prominent in the Burgess Shale Annelid worms in the Burgess shale

Anomalocaris hunts so are arthropods!!

Fossils of recognizable phyla in the Burgess shale

Mystery animals in the Burgess shale Wiwaxia corrugata Dinomischus

Figure 26.8 The Cambrian radiation of animals Causes of the radiation: 1.Predator-prey relationships originate. 2.Atmospheric oxygen reaches sufficient levels. 3.Homeobox genes evolve. (Ediacaran) 525 Burgess Shale PL PE D D R P

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA

Figure 33.1 Review of animal phylogeny

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA trochophore lophophore

Prominent Phyla of Lophotrochozoans

Figure Lophophorates: Bryozoan (left), brachiopod (right) LOPHOPHORE

The fate of the brachiopods Brachiopods Bivalves millions of years ago

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA trochophore lophophore

Figure 32.6 Body plans of the bilateria

Figure Cephalopods: Squid (top left and bottom left), nautilus (top right), octopus (bottom right)

Figure A chiton

Figure Anatomy of a clam Molluscs are coelomate, lophotrochozoan protostomes with a foot and a mantle

Ammonites - extinct since the Cretaceous, along with dinosaurs

Lophotrochozoans, a clade identified by molecular data, have the widest range of body forms.

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA lophophore

Nematodes – ecdysozoans with priminent medical significance hookworms Trichinella – the nematode that causes trichinosis

CRUSTACEANS as examples of ARTHROPODA

Figure Horseshoe crabs, Limulus polyphemus

Figure A trilobite fossil

Figure 33.x1 Insecta: beetle

Figure 32.8 Animal phylogeny based on sequencing of SSU-rRNA

Figure 32.7 A comparison of early development in protostomes and deuterostomes

Figure Echinoderms: Sea star (top left), brittle star (top right), sea urchin (bottom left), sea lily (bottom right),

fossil crinoids