Invertebrates of the Kingdom Anamalia



One interesting thing we learned while studying Invertebrates was that it often matters what symmetry the animal has in terms of how scientist classify them.

  • Spherical symmetry is when an organism can be cut into two identical halves by any cut that runs through its center. A ball has spherical symmetry. 
  • Radial symmetry is when an organism can be cut into two identical halves by any longitudinal cut through its center.
  • Bilateral symmetry is when an organism can be cut into two identical halves by one single longitudinal cut along its center which divides it into right and left halves.



There are many organisms in this phylum, including mollusks, clams, snails, oysters, and squid.
They have several mutual characteristics, the most common being a shell.
Cephalopods: Squids
All members of this phylum have radial symmetry. They have tentacles which catch prey by releasing nematocysts, small capsules that contain a toxin that is injected into prey or predators.

You may be familiar with these as natural sponges you can buy at the store in the art or beauty sections. Though they're animals and not plants, they can't think; they have no internal organs, no blood, no eyes, or ears, but can reproduce, digest food, and protect themselves.Sponges have no symmetry.

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