GLY150: INTRODUCTION TO OCEANOGRAPHY

University of North Carolina at Wilmington

I. General Classification of Living Organisms

Phylum

Class

Order

Family

Genus

Species

II. Origin of Animals (Kingdom Animalia/Metazoa)

Oxygen revolution - 2 billion to 400 million years ago
- Changed composition of atmosphere, more oxygen
- Made aerobic respiration practical
- First animals appear 900-700 m.y.a.

III. Invertebrate (without backbones) Phyla

Most Primative
- Protozoa - foraminifera and radiolaria
  - single celled, not true animals
  - zooplankton that feed off phytoplankton
- Porifera - sponges
  - most primitive true animals
  - no circulatory, digestive, respiratory or nervous system
  - suspension feeders
- Cnidaria - jelly fish, sea anemones and corals
  - Exhibit radial symmetry
  - No excretory, respiratory or circulatory system
  - Often have stinging tentacles or cnidoblasts
The Worms
- Platyhelmithes - flatworms
- Nematoda - round worms
- Annelida - segmented worms
Most Advanced
- Mollusca - snails, bivalves, octopi
  - Bilaterally symmetrical
  - Have well-developed nervous systems
  - Have flow-through digestive tracks
  - Secrete fitted shells
- Arthropoda - "insects of the sea", crabs, lobster, shrimp, copepods
  - Most successful of Earth's animal phyla
  - Have an exoskeleton
  - Have striated muscles
  - Have articulation
- Echinodermata - urchins, star fish, sea cucumbers, sand dollars
- Chordata - tunicates, salps
  - Have a tubular dorsal nervous system, notochord, and gill silts behind the oral opening

Have internal skeleton of calcified bone or cartilage
Have a skull which provides a secure housing for the brain, eyes and other sense organs
Most have jaws
The central nervous system is partially enclosed within the backbone
Evolved from the invertebrates