2011L Lec3 Porifera Spr08

2011L Lec3 Porifera Spr08 - QuickTimeTM and a TIFF...

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Phylum Porifera (“pore bearers”) The sponges QuickTimeu and a TIFF (Uncompressed) decompressor are needed to see this picture.
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The phylum name Porifera, meaning "pore- bearing”, contains approx. 10,000 living species, approx. 200 of which are freshwater. The remainder are marine. Sponges neither look nor behave like animals. They were not accepted as animals until the mid 19th century. Hence their grouping in the grade “parazoa” (alongside animals)
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Sponges come in diverse shapes, sizes and colours and range from shallow waters to abyssal depths. They are generally asymmetrical animals with sac-like bodies. They are sessile filter feeders that rely on system of self-generated water currents to bring in food and oxygen and to remove water products. QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture.
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Sponges have a long evolutionary history with more than 1000 fossil forms identified, the earliest of which is 550 million years old. Most ancient are the glass sponges that formed huge reefs which, by the time they disappeared 140 mya, were up to 7000 kilometers long (Great Barrier reef is 2000 kilometers) QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTimeu and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTimeu and a TIFF (Uncompressed) decompressor are needed to see this picture. In 1991 glass-sponge reefs covering 300 sq. kilometers were re- discovered in the Hecate Strait off the coast of western Canada
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The major lineages of evolution in animals Fundamental evolutionary divergence among metazoan Animalia, but based on what?
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Evolution and characteristics: Represent the cellular grade of animal evolution; they do not possess true tissues, merely specialized cell layers; epidermal cells on outer surface, collar cells in inner cavity. Considered offshoots that represent an evolutionary dead-end Evolved from colonial protozoan Cells from fragmented sponges can reaggregate and reorganize/regenerate the sponge organism, something not possible with animals that have tissues.
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animal-tre (a choanoflagellate colony?)
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Outline for today Basic architecture Types of canal systems Types of cells Types of skeletons Reproduction and development Classification QuickTime and a TIFF (Uncompressed) are needed to see th
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collar cells (“choanocytes”) produce water currents that flow through incurrent pores in sponge wall termed “ ostia ” (singular ostium) into a central cavity and out through the osculum . (A 10 cm tall sponge will filter as much as 100 liters/ day.) QuickTime and a TIFF (Uncompressed) decompressor are needed to see this picture. Basic
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2011L Lec3 Porifera Spr08 - QuickTimeTM and a TIFF...

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