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Here you'll learn about the evolution of marine organisms and the myriad of adaptations that enable them to survive in the world ocean. To emphasize evolutionary adaptations and ecological roles, the animal taxa are divided into three sections based on their predominant lifestyles: benthos, plankton, and nekton. Special emphasis is placed on the role of different groups of marine organisms in global biogeochemical cycles, especially the carbon cycle.

Table of Contents

Welcome to the Undersea World!
Marine Habitats: Definitions and Challenges
Evolution and Natural Selection

THE MICROBES

Introducing Marine Viruses
Introducing the Archaea
Introducing Marine Bacteria
Introducing the Phytoplankton

THE ANIMALS

Meet the Marine Animal Kingdom

THE BENTHOS

Benthic Protists
The Sponges
The Eumetazoa
The Benthic Cnidaria: Sea Anemones, Corals, and Hydrocorals
Bilateria: The Origins of Bilateral Symmetry
The Flatworms
The Ribbon Worms
What Makes a Mollusk?
The Bivalves
The Gastropods
The Chitons
The Aplacophora
The Monoplacophora
The Tusk Shells
The "Higher" Worms
Benthic Annelids: Polychaetes, Beard Worms, Girdle Worms and Sea Leeches
Echiura or Spoonworms
Sipuncula or Peanut Worms
What Makes an Arthropod?
The Marine Chilicerates: The Horseshoe Crab
The Crustaceans
The Barnacles
The Decapods: Shrimps, Lobsters and Crabs
The Mantis Shrimp
The Ostracods, or Seed Shrimp
The Peracaarids, Including the Amphipods
The Nematodes
The Cycloneuralia: The Priapulids, Loricifera, and Kinorhynchs
The Kamptozoa and Cycliophora
The Lophophorates: the Phoronids, the Brachiopods, and the Bryozoans
The Deuterostomes
Acorn Worms and Sea Angels
The Echinoderms
Sea Stars (Asteroidea)
Brittle Stars (Ophiuroidea)
Sea Urchins and Sand Dollars (Echinoidea)
Sea Cucumbers (Holothuroidea)
Sea Lilies and Feather Stars (Crinoidea)
What Makes A Chordate?
The Lancelets (Cephalochordates)
The Benthic Tunicates (Urochordata)


THE PLANKTON

Planktonic Protists
The Pelagic Cnidaria
The Hydrozoan Jellyfish and Siphonophores
The Scyphozoan Jellyfish
The Cubozoa, or Box Jellyfish
The Ctenophores
Pelagic Polychaetes
Pelagic Mollusks
Pelagic Arthropods, Mostly Crustacea
The Copepods
The Euphausiids, or Krill
The Chaetognaths, or Sea Arrows
Pelagic Tunicates
The Thaliacea: Pyrosomids, Dolioloids, and Salps
The Appendicularia, or Larvaceans

THE NEKTON


What is a Cephalopod?
The Cephalopod Body Plan
Squid Vision
Cephalopod Camouflage and Communication
Cephalopod Sensory Systems
Cephalopod Locomotion
Cephalopod Escape Responses
The Cephalopod Nervous System
The Cephalopod Circulatory System
Cephalopod Feeding
Cephalopod Reproduction
What is a Vertebrate?
Introducing the Fishes
Anatomy of a Fish
A Survey of Important Fishes
Agnatha, the Jawless Fishes
The Hagfish
The Lampreys
The Gnathostomata, or Jawed Fishes
The Chondrichthyes, or Cartilaginous Fishes
The Sharks
Blue Shark, the World Traveler
Hammerhead, PhD
The Great White Shark: the Landlord
Evolution of the Bony Fishes
Lobe-Finned Fishes, the Sarcopterygii
Ray-Finned Fishes, the Actinopterygii
The Herring-Like Fishes, the Clupeiforms
The Cod-Like Fishes, the Gadiforms
Tuna-Like Fishes, the Scombroids
Salmon-like Fishes, the Salmonids
The Birth of a Salmon
The Metamorphosis of a Salmon
A Salmon's Life at Sea
A Salmon's Journey Home
Salmon Recycling
Halibut-Like Fishes, the Pleuronectiforms
Rockfish-like fishes, the Percomorphs
The Rockfishes
The Sablefishes
Orange Roughy, or Slimeheads
The Snapper
Marine Reptiles: The Sea Turtles
Marine Birds
The Penguins
Albatrosses, Shearwaters and Petrels
Pelicans and Related Birds (Pelecaniformes)
Gulls and Related Birds (Charadriiformes)
What's a Marine Mammal?
The Carnivora
The Polar Bears
The Sea Otters
The Sirenia: Manatees and Dugongs
The Pinnipeds: Seals, Sea Lions, and Walruses
Cetaceans: A Case Study in Macroevolution
Climate Change and Cetacean Evolution
Modern Cetaceans: Whales, Dolphins, and Porpoises
Cetacean Feeding Strategies: Overview
How Baleen Whales Feed
How Toothed Whales Feed
Cetacean Behavior, Social Organization, and Communication
Cetacean Protection Behaviors
Cetacean Agonistic Behavior
Cetacean Social Behaviors
Cetacean Sexual Behavior
Cetacean Parenting
Cetacean Travel and Migration
Cetacean-Human Interactions
Fishing Impacts on Cetaceans
Geophysical Survey Impacts on Cetaceans
Low-Frequency Acoustic Sonar Impacts on Cetaceans
Acoustic Thermometry Impacts on Cetaceans
Whale Watching Impacts on Cetaceans
Ship Collisions with Cetaceans
The Effects of Environmental Contaminants on Cetaceans
The Effects of Climate Change on Cetaceans
Why Save the Whales?