Parazoa

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Parazoa
By Bonnie Anderson and Colette Carpenter

• No true Tissue

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What is a Parazoa?

• Members of the subkingdom of animals consisting
  of the sponges
• They are a multicellular organism

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Parazoa Facts

• Individual cells can sense and react to changes
  in environment
• Without specialized organs and tissues
• Filter food from water pumped through porous
  bodies nearly all are suspension/filter feeders
• Height can range from one to two centimeters

• Only 100 (about 9000 species) live in fresh
  water, rest live in marine
• Bodies consist of two layers of cells separated
  by a gelatinous region
• Cells tend to be totipotent (retain zygotes
  potential to form the whole animal)
• Most are hermaphrodites (having both female and
  male parts)

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Eumetazoa

• True Tissues

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Radiata and Bilateria

• Cambridge Campus
• Lorelei Swenson Nathan McLean
• Biology 1107

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Eumetazans

• Radiata and Bilateria are the major branches of
  Eumetazans.
• Eumetazans are animals that are symmetrical.

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Body Symmetries

• A) Radial animals are arranged like spokes of a
  wheel that radiate from the center. Any
  imaginary slice through the central axis would
  divide the animal into mirror images
• B) Bilateral animals have a left and a right
  side, and only one imaginary cut would divide the
  animal into mirror-image halves.

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Radiata

• Radial Symmetry
• Have aboral and oral ends.
• Two types of Radiata Cnidaria and Ctenophora.

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Cnidaria (Jelly Fish)

• Schphozoan Rhopalium
• Picture from http//biodiadac.bio.uottawa.ca/Thumb
  nails

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Ctenophora (Comb Jellies)

• Colloblast discharge organ of Ctenophora.

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Bilateria

• Two-sided Symmetry
• Bilateria have a dorsal (top) and ventral
  (bottom) side.
• Bilateria have an anterior (head) and posterior
  (tail) end.

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Body Plan

• Radiata- Diploblastic (two germ layers)
• Bilateria- Triploblastic (three germ layers)
• Germ layers are contcentric layers that form
  various tissue and organs of the body.

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Eumetazans

• Radiata or Bilateria?
• Its in the symmetry of the body!

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Acoelomate vs. Coelomate

• Jenni Olson and Sarah Ruther

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Acoelomate (without a coelom)

• Solid Body
• Lack a blood vascular system
• No cavity between gut and body wall
• Ex. Flat worm

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Coelomate

• True coelom (fluid filled cavity)
• Have vascular system
• Intestinal cavity lined with mesoderm
• Ex. Earth worm (segmented)

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Protostomes vs Deuerostomes(by Adam Curtis)

• Protosomes
• Spiral Cleavage
• Determinate Cleavage
• Blastopores becomes mouth
• Schizocoelous coelom formation

• Deuterostomes
• Radial cleavage
• Indeterminate cleavage
• Blastopore becomes the anus
• Enterocoelous coelom formation

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Definitions

• Radial Cleavage The planes of cell division are
  parallel or perpendicular to the developing
  embryo.
• Enterocoelous Coelom This manner of division
  starts with pockets forming on the mesoderm,
  which become hollow pockets or the coelom
  cavities.
• Mesoderm The third germ layer, a more evolved
  germ layer, usually forming muscles in
  development.

• Spiral Cleavage The planes of the cell division
  are diagonal to the axis of the developing embryo
• Schizocoelous Coelom Describes the manner in
  which the the coelom divides. Schizo many,
  thus the division of the coelom begins with
  splits in the mesoderm.
• Coelom A fluid filled body cavity that is
  completely derived from the mesoderm

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Deuterostomes

• Echinoderms
• Vascular system
• Food
• Gas exchange
• Locomotion
• Marine

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Protostomes

• Class Crustacea
• Exoskeleton
• Jointed Appendages
• Open Circulatory System

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Protostomes

• Class Diplopoda
• Other Classes
• Insecta
• Crustacea
• Trilobites
• Arachnida
• Mollusks
• Annelids
• Anthropoda

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Deutersomes

• Easteroidea
• Sea star
• Other Classes
• Crinodea
• Ophiuroidea
• Echinoderms