bio 207 chapter 9: marine reptiles, birds and mammals

vertebrates

descended from lobe finned bony fishes that possessed lungs

tetrapods

land dwelling vertebrates

Class Amphibia

amphibians, the first land tetrapods, delicate eggs deposited in water, must keep skin moist, frogs, toads, salamanders and newts

Class Reptilia

solved the problem of water loss and the need of water for reproduction, evolved from extinct amphibians and produce an amniotic egg, dry skin with scales, leathery-shelled eggs, poikilotherms and ectotherms, lizards, snakes, turtles and crocodilians

Order Chelonia

sea turtles, ancient group of reptiles, bodies enclosed in armor-like shell that is fused to the spine, cannot retract their heads, legs are modified into flippers

green turtles

coastal to tropic waters, numbers have dropped due to overexploitation and increased mortality, eat seagrasses and seaweeds, lack teeth but have strong biting jaws

hawksbill turtle

shell is reddish brown with yellow streaks, beak-like mouth to feed on sponges, sea squirts and barnacles

flatback sea turtle

feeds off coastal northern Australia on sea cucumbers, soft corals and other invertebrates

leatherback turtle

largest of all sea turtles, 3 m in length and 900 lbs, series of small bones buried in skin forming 7 ridges, open water species, eat jellyfish

sea turtle sex determination

based on temperature

lower temperature

male sea turtles

higher temperature

female sea turtles

sea turtle reproduction

return to land to reproduce, migrate to lay eggs on sandy remote beaches, eggs hatch after 60 days and offspring have a high predation rate

Order Squamata

sea snakes, Indian and Pacific oceans, tail for swimming, mate in ocean, ovoviviparous, feed on bottom fish, venomous

marine iguanas

inhabit Galapagos Islands, basket in the sun in large groups, eat seaweeds in cold ocean waters

Order Crocodilia

saltwater crocodile, inhabit mangrove swamps and estuaries of eastern Indian Ocean, Australia and Western Pacific Islands, aggressive, attack and eat humans

Class Aves

birds, homeotherms and endotherms, cover body with waterproof feathers that conserve body heat, achieve flight with hollow bones, eggs have hard shells resistant to water loss

bird oils

produced by a gland above the base of their tail and rubbed into feathers with their beaks during preening

seabirds

spend most of their lives at sea, mate for life, lay fewer eggs than land birds, webbed feet for swimming, predators of fish, squid, bottom invertebrates and plankton

penguins

flightless, stubby wing-like flippers for swimming, dense bones reducing buoyancy, nearsighted, adapted to cold temperatures

nearsightedness in penguins

eyes adapted for underwater vision

penguin cold tolerance

layer of fat under skin, waterproof feathers trap air and warmed by body head to protect against cold

emperor penguin mating

mate for life, males incubate a single large egg on top of his feet against his body for 64 days. female leaves to feed after laying eggs, lays eggs at the coldest time of the year so the egg hatches during the productive Antarctic summer when food is plentiful, parents feed chick for 5.5 months

tubenoses

large seabirds with distinctive tube-like nostrils and heavy beaks that are curved at the tip, spend months or years at sea, salt glands empty excess salts into the nostrils, skillful fliers, catch fish at sea, albatrosses, shearwater and petrels

pelicans

have a unique pouch below their large beaks, related to cormorants and frigatebirds

cormorants

long-necked black seabirds that dive and pursue their prey

frigatebirds

narrow wings and a long forked tail

gulls

make up the largest variety of seabirds, predators and scavengers, related to terns and puffins

shorebirds

wading birds without webbed feet, do not swim much, live in inland waters and the sea, plovers, sandpipers, rails, coots, herons, egrets, ducks

Class Mammalia

mammals, homeotherms and endotherms, hair of keratin to retain body heat, viviparous, females possess mammary glands

mammary glands

produces milk to nourish the young in mammals

Order Pinnipedia

seals, sea lions, fur seals and walruses, paddle-shaped flippers for swimming, rest and breed on land, evolved from early terrestrial carnivores, most live in cold water

Order Carnivora

sea otters and polar bears

Order Sirenia

manatees and dugongs

Order Cetacea

whales, dolphins and porpoises

seals

rear flippers cannot move forward, anterior flippers cannot be rotated backward, short neck, no external ear or testicles

sea lions and fur seals

posterior flippers can be moved forward, anterior flippers rotate backward, long neck, external ears and testicles

walruses

distinctive tusks protruding from mouth for defense and hold onto or anchor on ice, feed on bottom feeders, stiff whiskers act as feelers

sea otters

smallest marine mammals, lack blubber, traps air in dense fur, playful and intelligent, live in and around kelp beds, eat sea urchins, abalones, mussels, crabs and fish

polar bears

spend life drifting on Arctic ice, stalk and capture seals as they surface to breath, threatened by decrease of Arctic ice

manatees and dugongs

sea cows, front pair of flippers but no rear limbs, paddle-shaped horizontal tail, gentle vegetarians that feed on seagrasses and other vegetation, relatives of the elephant

whales, dolphins and porpoises

largest group of marine mammals, streamlined body, fish-like, pair of front flippers, fluke, blubber and blowhole

fluke

muscular tail in whales, dolphins and porpoises

baleen whales

toothless whales, rows of flexible plates that hang from the upper jaws, filter feeders that feed on plankton or krill

baleen

made of keratin

toothed whales

teeth adapted for a diet of fish, squid and other prey, blowhole has 1 opening

swimming

seals, sea lions and other pinnipeds: move their flippers
sirenians and cetaceans: move their tails and flukes up and down

diving

prolonged dives to considerable depths to obtain food, must be able to go a long time without breathing, hemoglobin and myoglobin, tolerant of lactic acid

apneustic breathing

taking several deep breaths followed by a rapid exhale

elastic tissues

in the lungs and diaphragms help fill and empty the lungs rapidly and efficiently

bradycardia

heart rate slows

echolocation

nature’s sonar, toothed whales and some pinnipeds emit sound waves that react back from surrounding objects, used to find prey or survey surroundings

melon

a fatty structure on the forehead of toothed whales that focuses and directs the outgoing sound waves

behavior

use a rich variety of vocalization and tactile and visual signals to communicate with each other, playfulness and mutual assistance are additional evidence

breaching

leaping in the air and loudly crashing on the surface, warning signal, a way of scanning the surface or shoreline, possible way to rid bay of external parasites

stranding or beaching

usually occurs when 1 or more members becomes disoriented either due to storm, illness or injury, some believe sonar may disorient cetaceans

migrations

most great whales move from winter breeding areas in the tropics to summer feeding areas in colder waters

cetacean reproduction

similar to land mammals, gestation lasts for 11 to 12 months

delayed implantation

allows pinnipeds to time the birth of pups with the arrival of pregnant females in feeding areas

calves

born tail first which allows placenta to stay attached as long as possible, will have oxygen until it is fully born and can reach the surface of the water, can live more than 40 years