Kingdom Animalia Ch 32 Lecture Objectives Animal Characteristics

Kingdom Animalia Ch. 32 Lecture Objectives Animal Characteristics 2. Embryology 3. Protostomes vs. Deuterostome 1.

The history of animals A Chanoflagellate

Individual choanoflagellate Choanoflagellates OTHER EUKARYOTES Sponges Animals Collar cell (choanocyte) Other animals Fig. 32. 3

Time Period Characteristics Paleozoic Era (542 -251 mya) Cambrian Explosion – earliest fossils - new predator prey relationships - rise in atmospheric oxygen - HOX gene complex mass extinction 460 Vertebrates on land 360 mya Mesozoic Era (251 -65. 5 mya) - Coral Reefs - Dinosaurs were dominant - See first mammals Cenozoic Era (65. 5 mya – present) - Followed by mass extinctions (large, non-flying dinos & marine reptiles) - Modern mammals & insects diversified

Cambrian Seascape Fig. 32. 7

Intercellular Junctions

Blastocoel Cleavage Endoderm Cleavage Blastula Ectoderm Zygote Eight-cell stage Gastrulation Blastocoel Archenteron Gastrula Blastopore Cross section of blastula Fig. 32. 2

Animal characteristics con’t. 6. Hox genes that regulate the development of body form

(a) Radial symmetry (b) Bilateral symmetry Figure 32. 8

Diploblasitc Ectoderm & Endoderm (radial symmetry) Triploblastic Eco, Endo + Mesoderm (bilateral symmetry)

Coelom Digestive tract (from endoderm) Body covering (from ectoderm) Tissue layer lining coelom and suspending internal organs (from mesoderm) (a) Coelomate Body covering (from ectoderm) Pseudocoelom Muscle layer (from mesoderm) Digestive tract (from endoderm) (b) Pseudocoelomate Body covering (from ectoderm) Tissuefilled region (from mesoderm) Wall of digestive cavity (from endoderm) (c) Acoelomate Fig. 32. 9

Protostome development (examples: molluscs, annelids) Deuterostome development (examples: echinoderm, chordates) Eight-cell stage Spiral and determinate Key Radial and indeterminate (b) Coelom formation Coelom Ectoderm Mesoderm Endoderm (a) Cleavage Archenteron Coelom Mesoderm Blastopore Solid masses of mesoderm split and form coelom. Mesoderm Folds of archenteron form coelom. Anus Mouth (c) Fate of the blastopore Digestive tube Mouth develops from blastopore. Anus develops from blastopore. Fig. 32. 10