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The most successful and abundant of the 2 groups of fishes (96% of all fish; about 27,000 species)

Include fish like tuna, cod, flounder, goldfish, and other familiar species

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Possess a hard, strong, lightweight skeleton made of calcium that supports them and is responsible for their success and diversity within the group

Boney fish usually have cycloid or ctenoid scales, which are thin, flexible, and overlapping

Cycloid scales have a smooth outer edge

Ctenoid scales have a toothed outer edge

Scales are made of bone, covered by a thin layer of skin and protective mucus

Bony fish are known for their boney gill flap, known as operculum

use of a swim bladder allows boney fish to stay neutrally buoyant in the water, while other fish will gulp air to get more buoyant

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Boney fish are subdivided into two major groups

Lobe finned fishes:

are largely extinct, but include lungfishes and coelacanths

Ray-finned fishes:

far more successful than lobe-finned

can be further divided into soft-rayed and spiny-rayed bony fish

Soft-rayed
- Cod
- Trout
- Herring

Spiny-rayed
- Bass
- Grouper
- Reef fish

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Oviparous reproduction
- External fertilization
- California Grunion is an example of this

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Approximately 200 million years ago, another group of air-breathing vertebrates, the mammals, evolved from now-extinct reptiles

Phylum Chordata

Subphylum: Vertebrata

Class: Mammalia

Long overshadowed by the dinosaurs until about 65 million years ago

All mammals share the following characteristics:

Warm-blooded (endothermic and homeothermic)

Four-chambered heart

Fur or hair (not feathers) to retain heat

Mammary glands to produce milk for young

Marine Mammals:

all marine mammals arose from land ancestors and have become adapted to a marine existence

streamlined body shapes reduce drag

limbs have been modified into flippers

evolved means of retaining large quantities of oxygen to facilitate long dives

concentrated (highly saline) urine

protected by the Endangered Species Act of 1985 and the Marine Mammal Protection Act of 1972; prohibits the capture, harming and/or killing of any marine mammal

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Pinnipedia are nearly exclusively marine animals
- Pinnipeds include Seals, Seal lions, Fur Seals, and Walruses

Seals, Sea Lions, and Walrus

Pinnipeds ("fin footed") evolved from a terrestrial carnivore

predators, feeding mainly on fish and squid

streamlined bodies for swimming

Thick layer of blubber for insulation, food reserves, buoyancy

Sea Otters and Polar Bears

both are marine mammals belonging to order Carnivora

the sea otter is the smallest marine mammal and lacks blubber

the sea otter has extremely dense fur, which traps air against the body for insulation

otters are found only in the Pacific Ocean, and have the densest fur of all animals

otters inhabit nearshore environments and dive to the sea floor to forage on mollusks, crustaceans, and echinoderms

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Keratin scales that are waterproof on the skin

obtain all of their oxygen through lungs

they lay shelled amniotic eggs

use behavior to regulate body temperature (ectothermic)

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Testudines (turtles)

Squamata (lizards and snakes)

Crocodilia (alligators and crocodiles)

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Evolution to flight dominates Avian characteristics

Lack teeth and use a gizzard to grind food

Some lack organs (having one ovary)

Hollow bones decrease weight

Feathers made of keratin

Endothermic for increased metabolism

Four-chambered heart - efficient blood circulation

one way air flow in respiratory track

large keel to anchor pectoral muscles

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Flexible endoskeletons made of cartilage

Well-developed jaws and paired fins

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Caudal fins:

propulsion with undulations of the body

Dorsal fin

stabilizes the organism from rolling

Pectoral and Pelvic fins

used for lift in the water column

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Sharp vision but can't distinguish colors

Very good Olfaction function (smell)

Lateral Line system:

allows to sense water vibrations

Send and sense electrical fields through pores in the skin

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Three types of gestation:

Oviparous: eggs laid outside of mother in thick mucus layer

Oviparous: retention of the eggs within the uterus but only the eggs nourishes the embryo

Viviparous: placental formation in the uterus

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Developed larger pectoral fins

Many have a venomous barb on the end of their tail to avoid predation