Kingdom Animalia Chapter 20

Kingdom Animalia Overview ◦ Heterotrophic, acquire food by ingestion ◦ Locomotion by means of muscles ◦ Multicellular, high degree of cell specialization ◦ Adult is diploid ◦ Reproduction usually sexual, with embryo undergoing developmental stages 30- 2

Kingdom Animalia cont’d Invertebrates- lack an endoskeleton of bone or cartilage ◦ All but one animal phylum are invertebrates Vertebrates- have an endoskeleton of bone or cartilage

Kingdom Animalia cont’d Common Name Phylum Porifera Sponges Phylum CnidariaCniderians Phylum PlatyhelminthesFlat Worms Phylum NematodaRound Worms Phylum MolluscaMolluscs Phylum AnnelidaAnnelids Phylum ArthropodaArthropods Phylum EchinodermataEchinoderms Phylum ChordataChordates

Animal diversity Fig. 30.1

Evolutionary Tree Fig Shows the division of Kingdom Animalia based on major evolutionary stages. 7 major stages ◦ Multicellularity ◦ True tissues ◦ Bilateral Symmetry ◦ Tube within a tube ◦ Coelomates ◦ Segmentation ◦ Jointed Appendages

sponges (Porifera) cnidarians (Cnidaria) flatworms (Platyhelminthes) roundworms (Nematoda) molluscs (Mollusca) annelids (Annelida) arthropods (Arthropoda) echinoderms (Echinodermata) chordates (Chordata) segmentation Jointed appendages segmentation protostomes deuterostomes coelomates pseudocoelomates tube-within-a-tube acoelomates, no body cavity radial symmetry, two germ layers true tissues, germ layers bilateral symmetry, three germ layers Multi-cellularity no true tissues, no germ layers ancestral protist

Evolutionary trends among animals Level of organization ◦ Cellular- no true tissues; sponges ◦ Tissue-have ectoderm and endoderm; cnidarians like hydra ◦ Organ-have ectoderm, endoderm, and mesoderm; majority of animals Type of body plan ◦ Sac-plan- incomplete digestive system; cnidarians ◦ Tube-within-a-tube plan-inner tube is digestive system, outer tube is body wall; two openings 30-8

Evolutionary trends among animals cont’d. Type of symmetry ◦ Asymmetrical-no particular symmetry ◦ Radial symmetry-circular organization, can be bisected in any plane to produce mirror images ◦ Bilateral symmetry-has definite right and left halves; only a cut down the midline will produce mirror images Type of body cavity ◦ Coelom-cavity that contains organs, and is lined with mesoderm ◦ Acoelomate-lacks a body cavity ◦ Pseudocoelomate-body cavity incompletely lined with mesoderm 30-9

Evolutionary trends among animals cont’d. Segmentation ◦ Repetition of body parts ◦ Molluscs and echinoderms are unsegmented coelomates ◦ Annelids, arthropods, and chordates are segmented coelomates ◦ Leads to cephalization and specialization of body parts Jointed appendages ◦ Specialized for locomotion ◦ In arthropods, may be adapted as mouth parts 30-10

General characteristics of animal phyla Table