Invertebrate Zoology
Week 1
Amanda Callaghan
Animal Diversity
Major 9 phyla;
1. Arthropoda
2. Platyhelminths
3. Nematodes 4
4. Mollusks
5. Sponges
6. Chordates
7. Echinoderms
8. Annelids
9. Cnidaria
Major splits; bilateral symmetry bi/triploblastic cells
Porifera; Sponges;
- Pore bearer, filter feeder largest outliers as asymmetrical organisms.
- Simple sponges have no nervous system, organs, respiratory or circulatory system
- Two layers of cells separated by jelly-like mesohyl.
Cnidaria; Jellyfish;
- 2 cell layers, jelly like middle
- Radial symmetry, jellyfish, coral and anemones.
- Have nematocytes – stinging cells.
Tissue Layers;
- Diploblast has an ectoderm [outside membrane], endoderm [inner membrane] and
non-living tissue in-between
- Triploblastic have ectoderm [outer] endoderm [inner] and mesoderm [middle living
tissue layer in which organs grow out of]
Protostome; gastrulation becomes the mouth [first indentation is the mouth]
Deuterostome; gastrulation becomes the anus [second indentation is the mouth
- Gastrulation occurs to allow O2 to get to the center of cells, blastopores form to reach
the center.
Week 1
Amanda Callaghan
Animal Diversity
Major 9 phyla;
1. Arthropoda
2. Platyhelminths
3. Nematodes 4
4. Mollusks
5. Sponges
6. Chordates
7. Echinoderms
8. Annelids
9. Cnidaria
Major splits; bilateral symmetry bi/triploblastic cells
Porifera; Sponges;
- Pore bearer, filter feeder largest outliers as asymmetrical organisms.
- Simple sponges have no nervous system, organs, respiratory or circulatory system
- Two layers of cells separated by jelly-like mesohyl.
Cnidaria; Jellyfish;
- 2 cell layers, jelly like middle
- Radial symmetry, jellyfish, coral and anemones.
- Have nematocytes – stinging cells.
Tissue Layers;
- Diploblast has an ectoderm [outside membrane], endoderm [inner membrane] and
non-living tissue in-between
- Triploblastic have ectoderm [outer] endoderm [inner] and mesoderm [middle living
tissue layer in which organs grow out of]
Protostome; gastrulation becomes the mouth [first indentation is the mouth]
Deuterostome; gastrulation becomes the anus [second indentation is the mouth
- Gastrulation occurs to allow O2 to get to the center of cells, blastopores form to reach
the center.
