Bio; Lecture 19; Survey of the Animal Kingdom

Bio; Lecture 19; Survey of the Animal Kingdom - Principles...

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Principles of Biology 2 BIO U103 February 26, 2007 Survey of the Animal Kingdom Porifera Choanocytes o Choanocytes are only found in sponges and in choanoflagellets o The hair-like portion is called the colar o The body produces mucus which is smeared on the colar hairs o Sponges are filter feeders o The flagella moves and creates a current o Food particles get stuck on mucus covered collar o It is then phagocytized inside the body, and then moved into an amoebocyte. o Amoebocytes are also called archaeocyte Pinacocytes o Line tubes where water is rushing through o These cells are flat Archaeocytes o Amoeba-like o Designed for digestion o Can differentiate into different sponge cells o Produce spicules Spicules o Thorn-like structures o Because of these, few predators eat sponges o Made out of calcium carbonate or silica. o Other sponges produce more flexible fibers from protein called spongin o These are used as bath sponges Mesohyl o Gelatinous region between the two layers of cells o Amoebocytes wander through this, and take up food and water o Cellular digestion Reproduction o Sponges are hermaphrodites—produce both sperm and eggs o Gametes arise from choanocytes or amoebocytes o Eggs are retained, but sperm are carried out the osculum by water current o Sperm are drawn into neighboring individuals and fertilize eggs in the mesohyl o Zygotes develop into flagellated swimming larvae that disperse from the parent o When a larva finds a suitable substratum, it develops into a sessile adult. Capable of extensive regeneration of lost parts Cnidaria Have a tissue level of organization - 1 -
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Principles of Biology 2 BIO U103 February 26, 2007 Are dipoblastic (ectoderm and endoderm) they do not have a mesoderm Have no muscle tissue since they do not have a mesoderm Radial symmetry Blind sac—gastrovascular cavity Mesoglia (gelatin like structure) Cnidarians are the
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This note was uploaded on 05/26/2008 for the course BIO 103 taught by Professor Potts-santone during the Spring '07 term at Northeastern.

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Bio; Lecture 19; Survey of the Animal Kingdom - Principles...

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