Key Features of Animals

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• Key Features of Animals
• ingest food
• multicellular
• no cell walls
• classified largely based on
• body symmetry
• digestive tract type
• skeletal type
• muscle type

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Blind Digestive Tract with Mouth/Anus
Open Digestive Tract with Mouth and Anus
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Hydrostatic Skeleton
Exoskeleton
Endoskeletons
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Circular and Longitudinal Muscles move Elongated
Bodies
Flexors and Extensors move Jointed Skeletons
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• Porifera
• asymmetrical body plan
• lack true tissues and organs
• internal skeleton made of spicules

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• Cnidaria
• radial symmetry
• jellylike mesoglea
• bag-like digestive tract with a single opening
• tentacles equipped with stinging cells

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• Platyhelminthes
• bilateral symmetry
• digestive tract with a single opening
• mesenchyme tissue

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• Annelida
• bilateral symmetry
• digestive tract with two openings (mouth and
  anus)
• coelom functions as a skeleton
• longitudinal and circular muscles
• body segmented
• closed circulatory system

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• Mollusca
• bilateral symmetry
• soft body usually with a shell
• digestive tract with two openings
• circular and longitudinal muscles

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• Nematoda
• bilateral symmetry
• digestive tract with separate mouth and anus
• longitudinal muscles only

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• Arthropoda
• bilateral symmetry
• paired, jointed appendages
• body divided into segments
• exoskeleton which must be molted
• flexor and extensor muscles

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• Echinodermata
• adults have pentaradial symmetry
• possess an endoskeleton that sends projections
  through the skin
• unique tube foot locomotory system