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26 Cards in this Set
- Front
- Back
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senescence
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unicellular forms can often divide without limit while multicellular forms have limited life span |
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Four basic developmental processes
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cell differentiation cell death (apoptosis) cell migration create increase in complexity but no change in genetic info |
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cell proliferation
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more cells produced by cell divisions
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cell differentiation |
cells change into various types for specialized functions (but all have the same genetic information) |
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cell death |
a programmed process that contributes to formation of body structures |
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Fundamental properties of animal body plan
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2. Fundamental symmetry 3. Number, development, and arrangement of germ layers 4. In Bilateria, the presence and arrangement of body cavities |
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Fundamental symmetry
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bilateral symmetry- split in two animals that move one end encounters environment and other end has propulsion usually cephalized ( sensors and brains in head) |
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Three basic cell types
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endoderm mesoderm |
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Formation of diploblastic zygote |
through cell movements, blastula becomes a hollow sphere gastrulation- forms first two germ layers |
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Blastopore can have two fates:
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forms the anus (deuterosomes) |
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Schizocoely |
protosomes |
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Enterocoely
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Deuterostomes |
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What do the primary germ layers go on to form in the animal? |
skin and nervous system endoderm gut and associated organs and structures mesoderm muscles, gonads, internal skeletons |
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Body cavities
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Pseudocoelomates Eucoelomates |
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Acoelomates
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the space between the ectoderm and endoderm is filled with mesoderm |
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Pseudocoelomates |
body cavity (pseudocoel) is derived form the embryonic blastocoel; partially lined with mesoderm (the gut has no mesoderm) |
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Eucoelomates
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body cavity is derived from embryonic mesoderm (completely lined with mesoderm) |
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thought to be at least two phyla: calcarea and siliea are loosely organized, little or no coordination can mechanically be broken down and can reform cells are totipotent- one cell of any type can form new animal |
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Characteristics of Parazoa
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sessile little apparent symmetry supporting 'skeleton' of mineralized spicules or a protein secretion, or both a specialized and unique cell type, choanocytes |
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Sponge 'body plans'
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small pumping chambers chambers lined with choanocytes water is pumped in thought the perforated body wall and out of an excurrent pore; food particles are filtered out and absorbed chanocytes pump with flagellae so chambers cannot be too big they become larger by add more chambers |
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Cnidaria
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diploblastic radial symmetry support via hydrostatic skeleton or visocoelastic skeleton, or both sessile and attached, or floating in water cnidocyte: stinging cells with special organelle, the nematocyst |
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Function of cnidocyte
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barbs dig in and fix in place propulsion from high pressure inject toxin hemolytic or neurotoxic |
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polyp form of cnidarians
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if mouth close water trapped in GVC longitudinal and circular muscles put pressure on trapped water tentacles catch food |
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medusa form of cnidarians
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swims by contracting 'muscles' around GVC, pushing against water springy (viscoelastic) mesoglea helps sustain rhythmic swimming tentacles may be very long |
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viscoelastic skeleton |
elastic and resumes original "relaxed" shape when force is removed mesoglea works this way |
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Hydrostatic skeleton
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water is deformable but not compressible basis of hydrostatic skeleton can change shape but not volume GVC works this way |
