Starfish

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Starfish
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Starfish Characteristics

• Invertebrates
• Phylum Echinoderm spiny-skinned animals
• Radically symmetrical - ie a bicycle wheel
  (usually have 5 arms, or multiples of 5)

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Beginning of life of a starfish

• starfish begin life microscopic, bilaterally
  symmetrical, free-swimming larva.
• Larva changes and becomes sessile, attaching to
  the ocean floor
• Metamorphosis occurs producing arms and an upper
  and lower surface

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2 types of sea stars (starfish)

• 1. Asteroideas arms connect to one another
• 2. Ophiuroideas arms do not connect to one
  another

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Locomotion

• Starfish move using tiny tube feet and the
  water-vascular system
• Water enters a tube, causing them to elongate,
  and the sucker attached to a surface
• Tube foot contracts, water is forced back,
  starfish moves forward

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Reproduction

• expel enormous numbers of eggs and sperm into the
  ocean
• fertilization is external.
• After fertilization, the tiny, transparent,
  bilaterally-symmetrical larvae (baby sea stars)
  travel many miles as they are swept along by
  ocean currents for about two months.
• Larva eat phytoplankton

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Diet

• carnivores (meat-eaters).
• Eat clams , fish, coral, sponges etcother
  animals.
• They push their stomach out through their mouth,
  releasing digestive enzymes and digest the prey.

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Anatomy

• do not have a brain they have a simple ring of
  nerve cells that moves information around the
  body.
• Eyespots (primitive light sensors) are at the
  tip of each arm.
• If a sea star's arm is cut off, it will
  regenerate (regrow).

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