Arthropods

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Arthropods
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Arthropods

• Largest group of animals
• 75 of all animals
• Segmented body
• Jointed limbs
• Exoskeleton
• Well-developed nervous system

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Segmented body

• Some have many segments that are the same
• Some have segments with specialized structures
  like wings, antennae, and claws
• Many have 3 segments called the head, thorax,
  abdomen

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Jointed Limbs

• Arthro joint
• pod foot
• Jointed limbs are body parts that bend at a joint
• Easier to move

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External Skeleton

• Exoskeleton
• Hard outer covering
• Made of chitin
• Stiff frame to support the body
• Suit of armor to protect organs
• Keeps water inside body and prevents drying out

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Well-developed Nervous System

• Head
• Brain
• Nerve cord
• Simple eyes to sense light
• Compound eyes to see images they have many
  light detectors
• Bristles to sense motion, vibration, pressure,
  and chemicals
• Antenna a feeler that senses touch, taste, or
  smell

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Centipedes Millipedes

• One pair of antenna
• Mandibles mouth parts that can pierce and chew
  food
• Centipedes?one pair of legs per segment
• Millipedes ?2 pairs of legs per segment
• Record for millipede legs is 752

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Crustaceans

• Shrimps
• Crabs
• Lobsters crayfish
• Pill bugs
• Most live in water
• Gills for breathing in the water
• Mandibles to eat
• 2 compound eyes on the ends of 2 eyestalks
• 2 pairs of antennae

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Arachnids

• Spiders
• Scorpions
• Mites
• Ticks

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More about Arachnids

• 2 main body parts cephalothorax and abdomen
• Cephalothorax head-thorax
• 4 pairs of legs (8)
• No antennae
• Cheliscerae claw-like mouth parts
• Some spiders have 8 eyes
• Kill more insects than any other animal
• Most spiders cannot pierce the human skin
• Ticks live in forests lawns
• The segments of a tick are joined as one
• Ticks are parasites that feed on blood
• Ticks can carry diseases like Lyme disease

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Insects

• Largest group of arthropods
• Weigh more than all other animals combined
• All have 3 main body parts
• Head, thorax, abdomen
• All have 6 legs (T)
• All have 2 antennae (H)
• 2 compound eyes (H)
• Mandibles to eat (H)
• 1 or 2 pairs of wings (T)
• Some have no wings
• Live everywhere but in the oceans

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More on Insects

• GOOD
• Important for farming pollination
• BAD
• destroy crops
• spread disease
• Bite people and suck our blood

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Complete Metamorphosis

• Metamorphosis ? the process of an insect changing
  form during its life cycle
• Most insects go through complete metamorphosis
  (4 Stages)
• Egg
• Larva
• Pupa
• Adult

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Incomplete Metamorphosis

• 3 Stages
• Egg
• Nymph
• Adult
• Nymph looks like adult but smaller no wings
• A nymph grows into an adult through molting
• Molting is when an animal sheds its exoskeleton
  (outgrows it)

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The end