Key Concepts Marine Reptiles Amniotic Egg Physiological Adaptations Marine Crocodiles

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1 Key Concepts The evolution of the amniotic egg gave reptiles a great reproductive advantage. The Asian saltwater crocodile lives in estuaries and is adapted to life in the marine environment. Sea turtles have streamlined bodies and appendages modified into flippers. Sea turtles mate at sea and lay eggs on the same beaches where the females hatched. Sea turtles may migrate long distances between their breeding grounds and their nesting beaches. The marine iguana of the Galápagos Islands is the only marine lizard. Sea snakes are mostly found in the shallow coastal waters of the Western Pacific and Indian oceans where they feed on fish and fish eggs. Shorebirds are adapted for finding food in shallow water and sand. A variety of bird species including, gulls, pelicans, and tubenoses are adapted to feeding on marine organisms. Penguins are the birds most adapted to life in the sea. Many marine reptiles and birds are endangered by human activities. Marine Reptiles Ancestors of modern reptiles appeared about 100 million years ago. Reptiles adapted for success on land, then used the same characteristics to return to the sea Modern-day reptiles include: crocodilians turtles lizards snakes Amniotic Egg An amniotic egg is covered by a protective shell amnion yolk sac allantois chorion Amniotic egg allowed longs development with less risk of predation Copulatory organs allow efficient internal fertilization Physiological Adaptations Advanced circulatory system Kidneys are efficient in eliminating wastes while conserving water Skin covered with scales and lacking glands decreases water loss Marine Crocodiles Largest living reptiles Feed mainly on fishes Drink salt water and eliminate excess salt through salt glands on their tongues Lives along the shore, where it nests Females reach sexual maturity at years of age, males mature at ~ 16 years.

2 Elevated nests contain eggs, incubation period is ~ 90 days Communicate with calls or barks Good navigational skills Sea Turtles Seven species inhabit world s oceans Adaptations to life at sea protective shells that are fused to the skeleton outer layer composed of keratin inner layer composed of bone carapace plastron leatherback turtle lacks shell Adaptations to life at sea shell is adapted for buoyancy/swimming fatty deposits and spongy bones add buoyancy front limbs are modified into large flippers back limbs are used for steering and digging nests Behavior generally solitary, interact for courtship remain submerged (up to 3 hrs) while at sea alternate between feeding and resting sleep on the bottom under rocks or coral in deep water, sea turtles can sleep on surface Feeding and nutrition have a beak-like structure instead of teeth green sea turtle is the only herbivore leatherback sea turtles adapted to eat jellyfish salt consumed are eliminated as tears Reproduction courtship nesting female can lay several clutches of eggs development and hatching Turtle migrations migrate hundreds to thousands of km females return to beaches where they were born to nest many hypotheses explaining method for sea turtle navigation over long distances: utilize smell and taste as well as auditory cues sense angle intensity of earth s magnetic field use sun Sea turtles in danger beach erosion/alteration artificial lighting near nesting beaches sea turtles are killed when trapped in fishing nests

3 turtles are hunted by humans dogs, cats and raccoons dig up nests and prey on eggs Marine Iguana The only marine iguana is in the Galápagos Islands Most are black, some mottled red and black absorption of heat high body heat allows swimming and feeding in cold water few predators but vulnerable to feral predators Feeding and nutrition herbivores with snout for grazing on seaweed some dive at high tide to feed on algae excess salt excreted by specialized glands Behaviors good swimmers intruders are attacked when they enter territory rarely result in serious injury Sea Snakes Descendants of lizards Adaptations to life in the sea scales tail nostrils single lung exchange gases through the skin can lower metabolic rate to use less O 2 Feeding and nutrition eat mainly fish, fish eggs and eels salt excreting gland Reproduction 3 oviparous species, others are viviparous congregate to mate have two penises - hemipenes gestation from 4 to 11 months can swim at birth Sea snakes and humans venom is toxic rarely bite humans eaten in Japan Seabirds 250 of 8,500 bird species live near or in the sea Seabirds feed in the sea Some spend months away from land Types of seabirds:

4 shorebirds gulls and their relatives pelicans and their relatives tubenoses penguins Adaptations for Flight Homeothermic High rate of metabolism Strong muscles, quick responses and coordination Advanced respiratory system with 4-chambered heart Excellent sight and hearing and large brain Adapting to Life in the Sea Large amounts of salt are consumed salt glands remove excess salt tears have high salt concentration Shorebirds Oystercatchers oystercatchers use long, orange bills to slice through adductor muscles of bivalve molluscs, pry limpets off rocks, crush crabs and probe mud Plovers have short, plump bodies nests in depressions or hollows on the ground Turnstones heavyset birds, with upturned bills used like crowbars to turn over stones and beach debris Sandpipers feed on small crustaceans and mollusks in sand Curlews long-billed curlew uses bill like a forceps to extract shellfish from their burrows Avocets and Stilts have long legs and necks and slender bodies avocets wade through shallow water, moving beak the water stilts probe the mud for small animals Herons, egrets and bitterns widespread skinny legs and long necks most stand still and wait for prey some stalk prey or frighten prey into motion Gulls and Their Relatives Gulls have webbed feet and oil glands They are not true ocean-going birds

5 Have enormous appetites but are not selective feeders Relatives of gulls include terns, skuas, jaeger birds, skimmers and alcids Gulls herring gulls are the most widespread feeding noisy, aggressive, efficient predators and scavengers may drop prey to break the shell open highly successful at finding food nesting highly gregarious; gather in large colonies not picky about nesting sites or materials both sexes assist in incubating 2-3 eggs chicks hatch in 3-4 weeks not uncommon for only 1 out of every 5 hatchlings to survive Terns small birds with brightly-colored bills and forked tails hunt by plunging into the water; will steal food usually gregarious nesters Skuas and Jaegers very aggressive omnivores and predators hawks or vultures of the sea jaegers will pursue other birds to steal their prey Skimmers (scissorbills) pupils that are vertical slits and a lower jaw protruding farther than the upper bill fly over water and create ripples that attract fish Alcids - include auks, puffins and murres look like penguins but are related to gulls convergent evolution ecological equivalents nesting and reproduction alcids gather in dense, cliff side colonies both parents care for 1 pear-shaped egg parental care of the young young murres plunge into the water to be joined by the parents alcid parents spend most of their time gathering food for chicks adult puffins abruptly leave chicks to learn to swim after 6 weeks of constant care Pelicans and Their Relatives Pelicans, gannets, boobies, cormorants, darters, frigatebirds, tropicbirds Have webs between all 4 toes Upper mandible is hooked in pelicans, cormorants and frigatebirds Many are brightly colored, or have head adornments Pelicans

6 large birds preferring warm latitudes and estuary, coastal and inland waters require a large fish population feed just under the water s surface gular pouch Boobies dive into the sea from m up to fish numbers of eggs may reflect food supply Cormorants lack oil glands, must periodically dry their wings Frigatebirds lightweight body and near 2 m wingspan cannot waterproof their feathers hence they feed by skimming surface with their bills pursue/attack other birds to steal prey Tubenoses Petrels, albatrosses and shearwaters Tubular nostrils on their beaks Glands secrete concentrated salt solution Glands in stomachs produces oil used for feeding hatchlings and defense Albatrosses gliders with wings nearly 3.5 m long most live in the Southern Hemisphere usually come to land only to breed elaborate courtship displays precede mating 1 egg is incubated by both Petrels small birds with long legs with fluttering flight feed with legs extended and feet paddling rapidly form long-term pair bonds for breeding live only in year-round cold water spot prey from the air, dive, and pursue prey by flying underwater Penguins Swift swimmers streamlined flat, webbed feet for steering leap from the water to breathe Eat fishes, squid and krill Eaten by leopard seals and killer whales Female emperor penguin lays 1 egg, which the male incubates while she feeds egg sits on his feet, covered by a fold of skin male can feed the chick crop both parents help by summer, the chick can feed itself,