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

Hydra

Portuguese Man of War

Coral