Unit 8 Chapter 28 Arthropods

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Unit 8Chapter 28Arthropods
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What is an Arthropod?

• Bilaterally symmetrical, segmented coelomates
• Segmented body, exoskeleton jointed appendages
• Appendages body outgrowths

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What is an Arthropod?

• Arthropods must molt (shed exoskeleton
  periodically)
• Arthropods have variety of respiration types
  gills, tracheal tubes book lungs
• Arthropods have complex digestive and excretory
  systems
• Mandibles (jaws) are used to classify arthropods

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What is an Arthropod?

• Arthropods have well-developed senses
• Pheromones chemical odor signals given off by
  animals (detected by others)
• Compound eyes
  visual structure with
  many lenses
• Simple eye visual
  structure with only one
  lens for detecting light

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What is an Arthropod?

• Arthropods reproduce sexually
• Some are hermaphroditic, most have internal
  fertilization
• A few have parthenogenesis new individuals
  develop from unfertilized eggs Ex social
  insects, such as bees, ants wasps

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Diversity of Arthropods

• Arachnids
• Includes spiders, scorpions, ticks mites
  (chiggers)
• Two body segments six pairs of jointed
  appendages, including 8 legs, 2 chelicerae
  (fangs) and 2 pedipalps (sensors)

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Diversity of Arthropods

• Crustceans
• Includes crabs, lobsters, shrimp, crayfish, pill
  bugs barnacles
• Two body segments 2 pair of antennae, 5 pair of
  legs, and numerous jaw feet

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Diversity of Arthropods

• Millipedes Centipedes
• Many body segments and paired legs
• Millipedes are herbivorous, while centipedes are
  carnivores
• Horseshoe Crabs
• These living fossils have remained unchanged
  for 200 million years

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Diversity of Arthropods

• InsectsMost successful class in terms of
  diversity
• Includes beetles,
  butterflies, ants bees,
  flies mosquitoes,
  and many others
• Three body segments,
  3 pair of legs, one pair
  of antennae, and wings

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Metamorphosis

• Series of changes in body shape and form during
  life history
• Incomplete M
  3 stages including
  nymph (smaller,
  immature version
  of adult)

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• Complete M 4 stages including larva
  (wormlike creature which eats and grows) and pupa
  (enclosed structure that changes into adult form)

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