Phylum Brachiopoda

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The Lophophorates

• Phylum Brachiopoda
• Phylum Bryozoa

2
Lophophorates

• All are sessile or sedentary adults that feed by
  means of delicate ciliated tentacles
• The system used in feeding is referred to a
  lophophore
• A circular or U shaped region around the mouth
  that bears 1-2 rows of hollow ciliated tentacles
• All species have a very simple gonad and a
  U-shaped digestive tract with some form of
  protective covering

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Phylum Brachiopoda

• Defining characteristics
• Body enclosed within a 2 valved shell, with the
  valves orientated dorsally and ventrally
• Why are lamp shells not members of the phylum
  Mollusca?

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Brachia
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Where Have All the Good Times Gone?

• Pedicle
• Brachiopods are a waning phylum, from fossilized
  12,000 spp. - 335 living spp.

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Local Representatives

• Lamp Shell (Glottidia pyramidata)

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Phylum Bryozoa

• Large and conspicuous colonies, usually not
  recognized as animals by lay people
• Incorrectly called seaweed.
• Primarily marine but some species are freshwater
• Bryozoans are the largest phylum of Lophophores
  and the most ecologically important

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Bryozoan Forms

• Some may be soft and bushy, (Bugula) leafy and
  crisp, (Thalamoporella) or hard and crust like
  (Membranipora or Schizoporella)

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Bryozoan Zooids

• Colonies are composed of numerous zooids, which
  do not exceed 1 mm.
• A zooid is one whole individual which can be
  generated or regenerated from the body wall of an
  neighboring individual
• Asexual reproduction produces up to 2 million
  identical individuals composing a colony
• Exhibit polymorphism, similar to hydroid colonies
• Feeding zooids resemble feeding hydrozoan polyps
  but have ciliated tentacles around the mouth
• Food is moved into a U shaped digestive tract
• Non feeding zooids adopt several different shapes
  and sizes
• Gamete producers, pinchers against biofoulers, etc

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Feeding Zooid
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Colonial Metabolism
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Reproduction and Lifecycle

• Individual zooids will frequently undergo
  degeneration into a brown body
• Can reproduce sexually, all colonies are
  hermaphroditic with individuals usually being
  dioecious
• Colonies grow from a single founder larva
  (ancestrula)