The Invertebrates
Chapter 12AIntroduction to the Animal
Kingdom
Zoology
The study of animals
Animals
• Eukaryotic and multicellular
• Have organized tissues• Consumers• About 95% are
invertebrates
Invertebrate
An animal without a backbone
Invertebrates
• Have skeletons–May be internal or external
• Much variety
The Invertebrates
Chapter 12BSponges and Cnidarians
Phylum Porifera
The pore-bearing animals
Sponges
• Porifera = “pore bearer”
• Live in water• Sessile• Can reproduce
sexually or asexually
Sponges
• Skeleton–Spongin–Spicules
• Collar cells• Filter feeders
Phylum Cnidaria
The stinging animals
Cnidaria
• Live in water• Radial symmetry–Umbrella-shaped• Medusa
–Tubular• Polyp
Radial Symmetry(Hydra)
Cnidaria
• Free-swimming or sessile
• Can reproduce sexually or asexually
Jellyfish
• Hydrostatic skeleton• Gastrovascular cavity–Only body opening is its
mouth
• Nerves, but no brain
Jellyfish
• Nematocysts–For food–For defense
• Swimming
Phylum Cnidaria
Other Examples
Portuguese Man of War