Diversity of Life - MOLLUSCA- · Mollusca - Classification 1. Gastropoda - snails and slugs If you...
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Transcript of Diversity of Life - MOLLUSCA- · Mollusca - Classification 1. Gastropoda - snails and slugs If you...
Porifera
Cnidaria Ctenophora Platyhelminthes Rotifera
Nematoda Nemertea Mollusca Annelida Arthropoda Bryozoa
Phoronida Brachiopoda Echinodermata Chordata
No true tissues
radial symmetry diploblastic
true tissues
Acoelomates
Deuterostomes
Bilateral symmetry triploblastic
Body cavity
Protostomes
Lophophorate phyla
Pseudocoelomates
Coelomates
A Phylogeny of the Animal Phyla
Mollusca - What makes them all molluscs?
Molluscs • triploblastic • soft bodied animals • protected by or possess a hard calcium carbonate shell
Mollusca - How do you build a mollusc?
Remember the standard coelomate body plan.
Step 2 - Put a fold of tissue dorsally
Step 1 - Expand the lower body wall
Step 3 - Put a shell over top
Mollusca - How do you build a mollusc?
End view Side view
Coelom
Shell
Mantle
Foot
Visceral Mass Foot
Mollusca - How do you build a mollusc?
This is the basic body plan from which all molluscs are derived.
Mollusca - Classification
1. Gastropoda - snails and slugs If you lift and twist the shell + visceral mass in the basic body plan, you make a snail.
Mollusca - Classification
2. Bivalvia - clams, oysters, mussels If you grow the shell down both sides of the body, you make a mussel or clam.
Mollusca - Classification
2. Cephalopoda - octopus and squid If you lose the shell and pull the foot down to make a series of tentacles, you make a squid or octopus.