animal evolution
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Animal Evolution. Precambrium Sea Multicellular Competition. Characteristics of animals. Animals are multicellular heterotrophic eukaryotes Ingestion to make inorganic chemicals Animal cells lack cell walls and are held together by proteins (collagen) Nervous Tissue and Muscle Tissue - PowerPoint PPT PresentationTRANSCRIPT
Animal Evolution
•Precambrium Sea•Multicellular•Competition
Characteristics of animals•Animals are multicellular heterotrophic eukaryotes
•Ingestion to make inorganic chemicals
•Animal cells lack cell walls and are held together by proteins (collagen)
•Nervous Tissue and Muscle Tissue
•Reproduce sexually with the diploid stage being dominant
Early Embryonic Development
Cleavage: mitotic divisionMultiple cells combine
Blastula: hollow ball of cellsHollow portion called Blastocoel
Embyronic LayersForm.Endoderm and Ectoderm
Traditional “Body Plans”•Major characteristics, embryonic development•Major branches called Grade
1. Parazoa-Eumetazoa: Formation of Tissues
2. Radiata-Bilateria:
3. Acoelomate-Pseudocoelomate-Coelomate
4. Protostome-Deuterostome:
Figure 32.5 Body symmetry
Radiata-Bilateria Dichotomy•Bilateralism forms: Dorsal, Ventral, Anterior, Posterior
•Cephalization: adaptation for movement.•Germ Layers: various layers of cells in development.
•Ectoderm: gives rise to outer covering, CNS•Endoderm: innermost layer, digestive tube•Mesoderm: b/w other two layers, muscle and other organs
•Diploblastic: two germ layers (radiata)•Triploblastic: Three germ layers (bilateria)
Protostome-Deuterostome Dichotomy
Protostome: mollusks, annelida, arthropodaDeuterostomes: Echinodermata, Chordata
•Cleavage: division of cells, •Spiral Cleavage: Protostomes, Early developmental fate, •Radial Cleavage: Deuterostomes, indeterminate cleavage
•Coelom Formation:
Blastophore Fate:Protostome: blastophore forms mouthDeuterostome: blastophore forms anus