Life in the World’s Oceans

Course Overview

An award-winning professor of marine science reveals the great diversity of life in the world’s oceans.

Course No. 1725
The Great Courses teams with the Smithsonian to produce a vivid exploration of life in the world’s oceans. In 30 lectures, Professor Sean K. Todd of the College of the Atlantic—one of the world’s leading marine biologists—takes you on a journey from the beginning of life on Earth four billion years ago to the environmental factors and international treaties shaping our oceans today.

With an engaging approach and infectious passion, Professor Todd shares cutting-edge research on marine-mammal intelligence, bioluminescence, deep-sea exploration, and the Smithsonian’s global studies, including the Great Barrier Reef.

You’ll discover life from microscopic phytoplankton (producing 50% of Earth’s oxygen) to the colossal blue whale. Explore the deep ocean’s sunless ecosystems and marvel at marine mammals’ tool use, cooperation, and self-awareness.

This course illuminates the ocean’s magnificence—and the urgency of protecting it.

Video Lectures

Module 1: Foundations of Marine Life

1. Water: The Source of Life (35 min)

• How water’s unique properties sustain life.

1. Ocean Currents and Why They Matter (33 min)

• How currents shape climate and marine ecosystems.

1. The Origin and Diversity of Ocean Life (37 min)

• Theories of life’s beginnings and bacteria’s dominance.

Module 2: Marine Ecosystems

4. Beaches, Estuaries, and Coral Reefs (30 min)

• Adaptations in dynamic coastal environments.

4. Life in Polar and Deepwater Environments (29 min)

• Productivity in icy and sunless depths.

4. Phytoplankton and Other Autotrophs (29 min)

• The oxygen producers fueling marine food webs.

Module 3: Ocean Inhabitants

7. Invertebrate Life in the Ocean (33 min)

• Diversity from microscopic to giant species.

7. An Overview of Marine Vertebrates (33 min)

• Classes of vertebrates thriving in the sea.

7. Fish: The First Vertebrates (32 min)

• Evolutionary adaptations for aquatic life.

Module 4: Marine Megafauna

10. Marine Megavertebrates and Their Fisheries (33 min)

• Human impact on apex predators.

10. Sharks and Rays (34 min)

• Myths and marvels of these ancient predators.

10. Marine Reptiles and Birds (31 min)

• Adaptations bridging land and sea.

Module 5: Marine Mammals

13. The Evolutionary History of Whales (30 min)

• From land mammals to ocean giants.

13. The Taxonomy of Marine Mammals (31 min)

• Five lineages of whales, seals, and more.

13. How Animals Adapt to Ocean Temperatures (31 min)

• Blubber, migrations, and survival strategies.

Module 6: Human Impact & Future

29. The Urban Ocean: Human Impact on Marine Life (35 min)

• Noise, plastics, and ecosystem threats.

29. Our Role in the Ocean’s Future (42 min)

• Solutions for ocean conservation.