Lecture01 NotesOutlineSp11

Lecture01 NotesOutlineSp11 - Lecture Outline for March 10,...

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Lecture Outline for March 10, 2009 Introduction; Features of Animals; Classification This lecture provides a brief introduction into traditional criteria used to classify animals (the approach we will follow), as well as a brief look at how this understanding is being revolutionized by modern molecular techniques. Chpt 32.1 – General Features of Animals - multicellular heterotrophs - no cell walls - active movement (in many) - sexual reproduction (in many. Often with complex behaviors) - similar embryonic development across taxa - unique tissues (except sponges) Chpt 32.2 – Animal Body Plan symmetry - 1. without symmetry – parazoa - - cell aggregates with specialization in function: lack symmetry, tissues and organs Examples? 2. with symmetry- - eumetazoa: - all have embryonic layers that form into tissues radial. Diploblastic – 2 tissue types – ectoderm and endoderm. Examples? bilateral. Triplobastic – 3 tissue types – ecto, meso and endo. Examples? Evolutionary advantage : forward movement and cephalization Segmentation (originally in annelids, arthropods and chordates) - Basic body "compartment," like cars on a train, and build up a body by adding more. It is a quick and simple way to add size. In animals that stay fully segmented, it helps make movement more efficient. allows development of various specialized limbs, such as antennae, pincers, walking legs, swimming legs, and feeding appendages. In chordates 1 st expressed during neuronal tube formation, becomes segmented and forms somites. Expression in muscle somites – precursors to adult vertebra. Expressed in ecto and mesoderm Advantages: 1. Redundant systems: each segment has complete set of adult organs 2. Locomotion more efficient – contract and expand autonomously body cavity – Coelom (tube within a tube) 1. acoelomate – sac-like 2. pseudocoelomate 3. (eu)coelomate Cavity between body wall and gut Importance: Placement of organs in
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separate locations Chpt 32.4 & 33.1 – Reevaluation of Animal Classification - molecular techniques are altering long-held views about animal classification Animals Cell aggregates Tissues Radial Bilateral Protostomes Deuterostomes -Protostomes are predetermined tissues, blastopore becomes mouth and anus, mesoderm splits and forms coelom -Deuterostomes – tissues indeterminant, blastopore becomes anus and second pore becomes mouth. Coelom arises from invagination of cells. Traditional Animal Phylogeny (~Figure 33.1) – based on symmetry - Tissues and Symmetry, along with various other characteristics - no symmetry; radiate symmetry; bilateral symmetry ID where tissues start ID where radial and bilateral start Reevaluation of Animal Phylogenies (~Fig 33.2) -Use anatomical, developmental (protostome, deuterostome), molecular. Segmented animals belonged together
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Lecture01 NotesOutlineSp11 - Lecture Outline for March 10,...

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