Marine Animals VERTEBRATES

OCN 201 Biology Lecture 8

Arthropods Segmented Worms The Animal Chordates

Family Tree Molluscs

Echinoderms Round Worms

Cnidarians

Bilateria

Ctenophores Radiata Flatworms

Placozoa Sponges Ancestral Protist Chordate Tree Invertebrates Vertebrates

What is a chordate ?

Animal with the following features: • Notochord • Dorsal hollow nerve cord • Pharyngeal slits (originally for feeding, later modified) • Post-anal tail

~4% of animals are chordates Tunicates salps • Pelagic or benthic • Colonial or solitary (or alternating) • Suspension feeders

Lancelets (cephalochordates) • Small, fish-like, suspension feeder • Can swim, but usually stays partly buried (as adults)

Amphioxus Chordate Phylogeny Invertebrates Vertebrates

What is a vertebrate ?

A chordate with a vertebral column 95% of all chordates are vertebrates Vertebrate diversity

Amphibians* 6%* Mammals* 9%*

Rep2les* 13%*

Fish* 55%*

Birds* 17%*

Marine vertebrate diversity

Other& 3%&

marine vertebrates ~= fishes

Fishes& 97%& The Major Fish Groups

• Jawless fishes (Agnatha)

• Cartilaginous fishes (Chondrichthyes)

• Bony fishes (Osteichthyes)

Agnatha Lamprey • No jaws; have rasping mouths • Earliest appearance of cartilaginous skeleton • Body covered with skin (not scales) • Parasites or Scavengers Hagfish Chondrichthyes (Cartilaginous Fish)

• Sharks, Skates, Rays, and Chimaeras • Skeleton of cartilage • Earliest appearance of jaws • skin covered with dermal denticles (like teeth) • Carnivores or Planktivores

Chondrichthyes: Planktivores

• Planktivores (filter feeders) are largest • Gaping mouth with small or no teeth • Gill rakers • Manta Ray (7 m across!) • Whale Shark (up to >10 m long!) Planktivores Whale Shark

Manta Ray

Chondrichthyes: Carnivores Cookie-Cutter Shark Lateral Line System

sensing movement

Electrosensory (sharks and rays) • Ampullae of Lorenzini • Detect very weak electrical signals given off by all living things • Find food in/on sediments Cartilaginous Fish

Osteichthyes (Bony Fish) • 22,000 species • From about 1 cm to 8 m • Surface to ≥ 8370 m • Most numerous, most diverse, most successful of marine vertebrates Osteichthyes Sensory Systems

• Good sense of sight and smell (except where eyes secondarily lost) • Auditory • Lateral Line System (water movement, displacement of water / pressure)

Herbivores

Herbivores (algae) Planktivores (Filter Feeders)

Anchovies Sardines H2O filter: gill rakers mouth

gill opening

gut

Used by the most successful groups Sardines, anchovies

Carnivores Parrot Fish

Tuna Mola mola: Ocean sunfish Most Massive bony fish: Up to 1300 kg and 3 m tip to tip

Feeds on gelatinous zooplankton

Bony Fishes Chordate Phylogeny Invertebrates Vertebrates

Car8laginous fishes Chordate( ChondrichthyesPhylogeny) Invertebrates Vertebrates Coelacanths

Amphibians Lobe-finned fishes Rep8les (Sarcopterigyii)

Birds

Mammals

Sturgeons etc. (Chondrostei) Ray-finned fishes Bony fishes (Ac#nopterygii) (Teleostei) Reptiles, Birds, and Mammals

Sea turtles

5 cosmopolitan species • Loggerhead • Leatherback • Hawksbill • Olive Ridley • Green Sea Turtle (Honu)

> 2 m long up to 1300 lbs Honu (Green Sea Turtle) • Chelonia mydas • Adults herbivorous (macroalgae) • Can submerge for 2 hrs when resting • Eggs laid on beaches - 2 months to incubate • Nesting females return to beach where born (natal beach)

Other Marine Reptiles Tropical West pacific/Indian Ocean • Crocodile - one living marine species • Sea snakes - 50 species. Venomous, no gills Seabirds

• albatross, shearwaters • gulls and terns • pelicans, cormorants, frigate birds • penguins

Mammals

Features: • Endotherms (warm-blooded) • Breathe Air • Have Hair • Live Young • Milk Production in Females Marine Mammals (Class Mammalia)

Carnivora - polar bears, sea otter, pinnipeds

Sirenians - dugongs and manatees

Cetaceans - whales and dolphins

CARNIVORA Pinnipeds (seals and sea lions) Polar Bears

Sea Otters

Ursus maritimus

Enhydra lutris Sirenians

• dugongs and manatees • Herbivores - eat sea grasses • Near shore inhabitants of warm tropical waters • Only ~2300 alive today • Stellar sea cow hunted to extinction

Cetaceans

Includes the whales, dolphins and porpoises Two Cetacean Suborders:

• Mysticetes (11 living species) – large – baleen whales - filter feeders – 2 blowhole openings

• Odontocetes (about 67 species) – smaller – toothed whales, dolphins, and porpoises – 1 blowhole opening

Mysticetes (baleen whales)

Use complex vocalizations or “songs” for communication Baleen (Mysticetes)

Humpback Bubble Net Odontocetes (toothed whales)

Use squeals, chirps and clicks for communication, echolocation and stunning of prey

Questions?