Why study invertebrate biology?

• 1) TECHNICAL REASON: to learn proper names of animals

• 2) CONCEPTUAL REASON: to learn animal relations & history

• 3) PRACTICAL REASONS:

  • invertebrates are food for many vertebrates (wildlife management)
  • causes of human disease & agricultural pests are invertebrates
  • knowing basic invertebrate biology yields insights into human biology, evidence of a common heritage:

    • field of immunology founded by Metchnikoff in 1883 based on the simple observation of clumping amebocytes in injured starfish larvae; he later won the Nobel prize in medicine
    • model invertebrate systems (e.g., nematodes, fruit flies) help us understand gene function and possible role in human disorders
    • sea squirt endostyle is homologue of human thyroid gland

• 4) AESTHETIC REASONS: for the shear joy of discovering extraordinary forms and abilities of animals ('tis a curious world)

  • Impressively large body sizes:

    • the largest living invertebrate is 19 m long, weighs over 500 kg, and can swim at 25 kph in water! (giant squid)
    • crabs may have a leg span exceeding 4 m! (Japanese spider crab)
    • earthworms may exceed 3 m in length! (Australian earthworm)
    • marine ribbon worms may reach 30 m in length! (Nemertea)
    • worms 2 m long & 3-4 cm diam. have no gut! (Vestimentifera)

  • Impressively large body parts:

    • worms with a proboscis 350X longer than body! (Echiura)
    • crab with one claw at 40% of total body weight! (fiddler crab)

  • Impressive abilities, some dangerous to humans:

    • shrimp that can snap fish out of the water, or pulverize a snail shell by pounding! (mantis shrimps)
    • snails that paralyze fish & swallow them whole! (cone snails)
    • many are deadly to humans as parasites (nematodes) or are vectors for serious human diseases (mites, mosquitoes)

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