Phylum Arthropoda

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Phylum Arthropoda

• Biology I Honors

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Examples

• Subphylum Chelicerata - Class Arachnida
• Spiders and mites
• Ticks
• scorpions

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Examples

• Subphylum Crustacea
• Crabs, lobsters, shrimp, barnacles

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Examples

• Subphylum Uramina - Class Insecta
• Grasshoppers, mosquitoes, ladybugs, bees,
  butterflies, ants, etc.
• Greatest number of species among animals

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Others

• Centipedes and millipedes
• Horseshoe crabs
• virtually unchanged over the past 500 million
  years. Living Fossil
• More closely related to spiders than to
  crustaceans (crabs)

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Habitat

• EVERYWHERE
• Crustaceans
• Mostly aquatic
• Arachnids
• Mostly terrestrial
• Insects
• Mostly terrestrial

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Symmetry

• Bilateral

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of Tissue Layers

• 3

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Support/Skeletal

• Exoskeleton
• Made of chitin
• Jointed appendages

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External Anatomy
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Male or Female
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External Anatomy
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External Anatomy - mouthparts
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Male and female
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Muscular

• Well developed muscles
• Work with exoskeleton
• Complex movement
• Flight, etc.

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Digestion

• Complete

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Respiration

• Arachnids
• Book lung

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Respiration

• Crustaceans
• gills

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Respiration

• Insects
• Trachea
• Spiracles openings to the outside of the body
• Trachea tubes that connect spiracles to cells
  of organs allow oxygen to pass to all body
  cells
• Insect pulses abdomen so that air can move in and
  out through tubes

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Excretion

• Insects
• Land arthropods have excretory organs to minimize
  water loss
• Malpighian tubules

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Circulation

• Open

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Nervous System

• Well Developed
• Ventral nerve cord
• Ganglia
• Sensory organs
• Antennae
• Sense chemicals in the environment
• Compound eyes
• View movement well

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Temperature regulation

• Ectothermic

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Reproduction

• Sexual
• Metamorphosis common, though not all arthropods
  have it
• Larval form completely different from adult
• Reduces competition between parents and offspring