Animal Diversity - - Most animal phyla appear during...

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Animal Diversity What are Animals? - Multicellular - Unique tissues: muscle and nervous - Lack cell walls (unlike plants/fungi) - Structured support provided by extracellular proteins (e.g. Collagen) - Unique intercellular junctions: - Tight junctions - Desmosomes - Anchors the cells together - Gap junctions Evolutionary History of Animals - Evidence of chanoflagellate relationship - Near identical morphology with sponge cells - Similar collar cells found in other animals, but no other eukaryotes - DNA sequence similarity - Late Proterozoic - First macroscopic animal fossils 575 MYA (Ediacaran biota) - Basic body plans established - Radial symmetry - No matter how you slice it it’ll be symmetric on both sides - Bilateral symmetry - Along the axis you’re symmetric on either side - Segmentation - Repeating units in organism
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- Cambrian - What lead to the Cambrian Explosion? - Increase in atmospheric O2 - Diversifying selection (new predator prey interactions) - Hox gene duplications - Animal Phylogeny
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Unformatted text preview: - Most animal phyla appear during Cambrian explosion Animals- Diversity- 75% are insects- 30% are beetles- 5% are vertebrates- 1% are mammals- Reproduction- Most reproduce sexually- Diploid stage dominates life cycle- Flagellated sperm; large non-motile eggs- Development- Zygote undergoes cleavage; forms hollow ball (blastula)- Blastula then develops into gastrula- Lining of gastrula: endoderm, exterior cells: exoderm- Hox genes- Master regulatory genes that dictate developing body- Highly conserved; linear correlation between body axis and chromosomal position- Small mutations lead to big changes in form- Gene duplications provide greater anatomical complexity- Body Plans- Symmetry- Radial symmetry- Bilateral symmetry- Tissues- Diplobastic- Exoderm- Endoderm- Triplobastic- Exoderm- Endoderm- Mesoderm- Specialized tissues:- Muscles- Neural- Body Cavities- Coelem: body cavity- Protostome/Deuterostome- Protostome: Mouth- Deuterostome: Anus...
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This note was uploaded on 09/21/2011 for the course BSC 2010 taught by Professor Bowes during the Spring '08 term at University of Florida.

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Animal Diversity - - Most animal phyla appear during...

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