1. Other facets of invertebrate embryology

2. Stages of development Egg and sperm Fertilized embryo
Cell division resulting in a multicellular embryo (cleavage)
Radial cleavage
Spiral cleavage
Morula--solid ball of cells
Blastula-hollow ball of cells
Gastrula

3. The outcomes of gastrulation
Diploblasty
Formation of the primitive gut
Name of the entrances and exits
If the first opening becomes the mouth, protostomates
If the first opening becomes the anus, deuterostomates

4. Formation of mesoderm in the eucoelomates
Protostomates
Solid mass of mesodermal cells in blastocoel
Schizocoely--split in the mesoderm to form the coelom
Deuterostomates
Budding off of the archenteron
enterocoely

5. Outcomes in the pattern of development
Protostomates, have spiral cleavage
Determinate--cell futures are predictable
Deuterostomates, have radial cleavage
Indeterminate--cell futures are not predictable at the eight cell stage

6. Phylogenetic relationships
Protostomates
Annelida
Mollusca
Arthropoda
Deuterostomates
Echinodermata
Chordata
Invertebrate chordates
Vertebrates

7. Origin of the eucoelomates
Relationship to the platyhelminthes
Larval relationships
Protostomates have a larval stage = trochophore
Platyhelminthes larvae = Muller’s larvae