Life in the Ocean: A Diverse Menagerie

Major Marine Groups

• Fish: 30,000+ species (tuna, salmon, bass, etc.).
• Marine mammals: Whales, dolphins, seals, sea lions, walruses—air-breathing, live birth.
• Seabirds: 10,000+ species (gulls, terns, auks).
• Reptiles: Sea turtles (air-breathing), saltwater crocodiles (breath-holding).
• Invertebrates: Jellyfish, squid, octopus, crabs—millions of species, ecosystem foundation.
• Plankton: Phytoplankton (algae) and zooplankton (microscopic animals)—base of the marine food web.

This biodiversity supports global food security, climate regulation, and immense ecological value.