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Gelason notes 311 - Dr Gleason Chapter 32 Intro to Animal...

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Dr. Gleason 3-11-08 3-13-08 Chapter 32: Intro to Animal Diversity General Characteristics of Animals o Multicellular o Heterotrophic: can’t make own food, depend on food source other than self o Structural proteins (collagen): b/c animal cells don’t have cell wall, must maintain structure by collagen o Impulse conduction and movement (nervous and muscle tissue) o Require O 2 for respiration o Reproduce sexually (mostly) and/or sexually o Mobile for at least part of life cycle o Life cycle with embryonic period (development through mitotic divisions: cleavage) Embryonic development Fig. 32.2 What makes sure parts are in the right spots? o Homeobox genes (in all eukaryotes) Produce regulatory proteins o Hox genes (homeobox genes in all animals) Control cell division and differentiation
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Highly conserved, number increases with animal complexity Important Points!!! o Evolution of animals may have begun 1.5 billion years ago. o All life confined to seas for much of animal evolution o More animals diversity in water than on land More Important Points!!! o Animals: monophyletic o Animal ancestors: Probably colonial flagellated protists o Keys to further evolution: Division of labor Major Groups o Invertebrates: No backbone Butterflies, snails, dragonflies, etc... o Vertebrates: Backbone with bony segments Lizards, humans, snakes, etc…
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Number of Animal Species o Approximately 1.3 million described o Estimates of 10-200 million! o 95% of all animal species are invertebrates!!! Fundamental Body Plan Variables o Symmetry o Tissues o Body Cavities o Developmental Pathways Symmetry o No symmetry: sponges have no symmetry! o Radial symmetry (radiata): cut across more than one plane and be symmetrical; parts arranged around central axis; Associated with animals that move slowly or immobile o Bilateral symmetry (bilateria): cut across one plane and be symmetrical; right and left halves that are mirror images of each other;
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