Arthropoda and Echinodermata

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Arthropoda and Echinodermata
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Arthropods General Characteristics

• Most diverse group
• Insects, Crustaceans, Millipedes, Centipedes,
  Arachnids (Spiders, scorpions)
• Coelomate
• Bilaterally symmetrical
• Exoskeleton, jointed appendages, segmented body
• Open circulatory system

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Arthropoda Four Subphyla

• Trilobita (extinct)
• Chelicerata horseshoe crabs, spiders,
  scorpions, mites, ticks
• Crustacea - crabs, crayfish, pill bugs, lobster,
  shrimp, barnacles
• Uniramia Centipedes, millipedes, insects

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Subphylum Chelicerata
Class Arachnida Spiders
Top Horseshoe crab. Left Scorpion. Bottom
Dust mite
Tick
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Subphylum Crustacea
Barnacles
Crabs, lobsters and shrimp!
Roly-polys. Aka Pillbugs
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Subphylum Uniramia, Class Chilopoda Class
Diplopoda Centipedes and Millipedes
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Subphylum Uniramia, Class Insecta

• Put together, outweigh all terrestrial animals
  (Over 800,000 species!)
• One ton of ants and termites for every human on
  earth
• Six legs
• Jump
• Walk
• Wings
• Single pair of antennae

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Class Insecta
Butterfly Emerging
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Echinodermata (spiny skin) General
Characteristics

• Sea stars, sea urchins, sand dollars, sea
  cucumbers, sea lilies, brittle stars
• 5-part radial symmetry
• Water vascular system
• Tube Feet Sea star moving
• 5 classes in the phylum

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Asteroidea - Seastars
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Echinoidea Sea urchins and sand dollars
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Sea cucumbers, feather stars, brittle stars
Class Ophiuroidea Brittle star (above), Basket
star (below)
Class Holothuroidea Sea cucumbers
Class Crinoidea feather star (left), sea lily
(right)