Animals Chapters 27, 28, 29[1]

Animals Chapters 27, 28, 29[1] - Animals Chapters 28-30...

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Animals Chapters 28-30 Ecdysozoa: The Animal Kingdom What is an animal? -multi-cellular eukaryotes -cells are specified to carry out specific functions -cells are organized into tissues -they are exclusively heterotrophs (meaning they eat from another) -capable of locomotion in some point in their life -nervous systems and muscles -sexual reproduction Animal Classification -35 phyla including amphibians, reptiles, birds, mammals, sponges, jellyfish, worms, mollusks, insects, crustacea like lobster -5% of all animals have a backbone (are vertebrates) - majority of animals live in marine environments Animal Evolution -general concept is that animals arose only once -2 informal divisions of animals: Protozoa, and Eumetazoa-based on body plan organization -Parazoans (no symmetry) -Eumetazoans (radial symmetry like spoke of a bike) (Bilateral symmetry arranged as a mirror image only a central axis Body Embryonic Organization -Animals develop from 2 or 3 embryonic tissue layers- germ layers 1) Ectoderm-outer skin layer 2) Endoderm-may become muscle structures 3) Mesoderm-(develops into internal organs) presence of this results in triploblastic ( has all 3) -presence or absence of certain layers has to do with what animal you become Triploblastic Body Plans 1) Acoelomates-all three layers are in contact with each other 2) Pseudocoelomates- the ectoderm/mesoderm touch, endoderm separated 3) Coelomates-the mesoderm extends out and wraps around internal organ **See below for 2 types: Protostomes/Deuterostomes
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Coelomates have two diffo types I. Protostomes 1 st the mouth the blastopore (a pore that develops in embryo becomes the mouth) -Spiral cleavage -Displays skitzocoely-splitting of mesoderm determinate cleavage cells of the embryo turn into certain body parts All are invertebrates and have a coelom The coelom arises b/c of a tube-in-a-tube body plan -coelom has many advantages: 1) digestive tube independent of cell wall, 2) serves as a hydrostatic skeleton 3) provides a volume thru which wastes, nutrients, gases can be transported
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Animals Chapters 27, 28, 29[1] - Animals Chapters 28-30...

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