Lecture 10: Protostomes

Lophotrochozoa contain 13 phyla divided into what four

rotifers

platyhelminthes (flatworms)

annelids (segmented woms)

mollusks

Ecdysozoa contain what four major phyla

nematodes (round worms)

tardigades (water bears)

onychophors (velvet worms)

arthropods (insects, spiders, crustaceans)

how do protostomes different from deuterostomes

1) embryonic development of mouth before anus

2) isolated early embryonic cells cannot develop into a complete embryo

3) coelom formed by splitting of mesodermal cell blocks

Segmented worms

shape, lineages

repeated units separated by septa

Polychaeta (lugworm)

Oligochaeta (earthworm)

Hirudinea (leeches)

Mollusks lineages

chitons (dorsal shell of plates)

bivalves (clams)

gastropods (slugs)

cephalopods (octopuses)

the ______________ contains the radula

what is the radula

mouth

feeding structure made of sharp plates

Ecdysozoans have (continuous/discontinuous) growth

discontinuous

Tagmata

Prominent body regions in arthropods

Arthropods

importance? three features?

most imp ecdosozoans

1) segmented body (tagmata)

2) exoskeleton of chitin

3) jointed limbs

four arthropod lineages

1) myriapods

2) insects

3) crustaceans

4) chelicerates