Kingdom Animalia

1. What are animals? Animals eat to live: ‘ingestively’ heterotrophic Multicellular lack a cell wall Kingdom Animalia

2. Sponges are the oldest known animals in the fossil record and are similar to protistan choanoflagellates. Origins and Early Diversification of Animals Sponge (an animal) Choanoflagellate (a protist) Water current out of sponge Choanoflagellate cell Sponge feeding cell Interior of sponge Food particles Water current into sponge Water current

3. There are about 35 Phyla in Kingdom Animalia We’ll review approximately 14 of these Four basic features vary in different animal body plans, and are the basis for grouping animals into different phyla: 1. Embryonic tissues 2. Body symmetry 3. Presence of a body cavity 4. Details of early development Origins and Early Diversification of Animals

4. Tissue= highly organized and functionally integrated group of cells All animals but sponges have tissues arranged in layers in their embryos 1. Tissues Parazoa (Phylum Porifera) No tissues Tissues present Eumetazoa (all other phyla)

5. In animals with embryonic tissues, the tissues are arranged in layers Endodermdigestive tract, liver, lungs Mesodermcirculatory system, muscles Ectodermskin, nervous tissue 1. Tissues • There may be 2 or 3 layers: • Diploblastic endo & ecto only • Triploblastic all 3

6. An animal’s body plan may have no symmetry (sponges), or show radial or bilateral symmetry 2. Symmetry Asymmetry Radial symmetry Multiple planes of symmetry Posterior Single plane of symmetry Dorsal Bilateral symmetry Anterior Ventral

7. Animals that are diploblastic show radial symmetry Animals that are triplobastic show bilateral symmetry (1. And 2.) Tissues and Symmetry Parazoa (Phylum Porifera) No tissues Diploblastic, radial symmetry Radiata (Phylum Cnidaria & Ctenophora) Tissues present Eumetazoa Triploblastic, bilateral symmetry Bilateria All other Phyla

8. Animals with bilateral symmetry are capable of unidirectional movement Mesoderm made musculature possible Together: directed movement and hunting Significance of Tissues and Symmetry

9. A coelom (body cavity) develops within mesoderm tissue in most triploblasts. The coelom provides space in which organs can develop and acts as a hydrostatic skeleton in soft-bodied animals. Some triploblasts have a pseudocoelom, which develops between mesoderm and endoderm and functions just as a coelom does. 3. Fluid-filled body cavities

10. Body plans of the bilateria

11. Hydrostatic skeleton of a nematode Muscle Fluid-filled pseudocoelom Gut Body wall

12. Coordinated muscle contractions result in locomotion Muscles relaxed Muscles contracted Muscles contracted When the muscles on one side contract, the fluid-filled chamber does not compress. Instead, the animal bends. Muscles relaxed

13. 3. Bilateria animals either have no coelom, pseudocoelom, or a true coelom Phylum Platyhelminthes No coelom Phylum Nematoda Phylum Rotifera Pseudocoelom Bilateria Coelom Coelomates: All other Phyla

14. The last feature used to categorize animal body plans deals with details of the early development of animals Animals develop from a single-celled zygote through a process called gastrulation 4. Early events in embryogenesis

15. Figure 32.1 Early embryonic development (Layer 1)

16. Figure 32.1 Early embryonic development (Layer 2)

17. Figure 32.1 Early embryonic development (Layer 3)

18. Among coelomates, there are 2 groups: Protostomes: spiral cleavage, mouth develops first, coelom develops within blocks of mesoderm. Deuterostomes: radial cleavage, mouth develops second, coelom develops from mesoderm cells that bud off the endoderm. Early events in embryogenesis

19. Figure 32.7 A comparison of early development in protostomes and deuterostomes

20. Three phyla of Coelomates have charateristics of both protostomes and deuterstomes These are the Lophphorate Phyla Odd group out

21. Bilateria Protostomia Phylum Mollusca Phylum Annelida Phylum Arthropoda Spiral cleavage, mouth first, etc. Lophophorate Phylum Bryozoa Phylum Phoronids Phylum Brachiopoda lophophore Bilateria Radial cleaveage, mouth second, etc. Deuterostomia Phylum Echinodermata Phylum Chordata

22. Data based on nucleotide sequence of the small subunit ribosomal RNA (SSU-rRNA) Early branches still the same Deuterostomes still the same Molecular Systematics is moving some branches around on the phylogenetic tree of animals

23. Animal phylogeny based on sequencing of SSU-rRNA

24. Differences: Protostomes divided into 2 groups Lophotrochozoaannelids,molluscs, lophophorates Ecdysozoanematodes, arthropods Molecular Systematics is moving some branches around on the phylogenetic tree of animals Trochophore larvae of annelids and molluscs

25. The Ecdysozoa are defined by molting Nematodes and arthropods shed their exoskeleton as they grow, a process called ecdysis

26. Animal phylogeny based on sequencing of SSU-rRNA