1. © 2006 Thomson-Brooks Cole Chapter 11 Reptiles and Birds

2. © 2006 Thomson-Brooks Cole 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.

3. © 2006 Thomson-Brooks Cole Key Concepts 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. Sea turtle populations are endangered by a number of human endeavors.

4. © 2006 Thomson-Brooks Cole Key Concepts The marine iguana of the Galápagos Islands is the only marine lizard. Several species of venomous sea snake live in the marine environment. Shorebirds have long legs for wading and thin, sharp bills for finding food in shallow water and sand.

5. © 2006 Thomson-Brooks Cole Key Concepts 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.

6. © 2006 Thomson-Brooks Cole Marine Reptiles Reptiles adapted for success on land, then used the same characteristics to return to the sea and gain success there as well Modern-day reptiles include: –crocodilians –turtles –lizards –snakes

7. © 2006 Thomson-Brooks Cole Amniotic Egg An amniotic egg is covered by a protective shell and contains: –amnion—a liquid-filled sac in which the embryo develops –yolk sac—sac where yolk (food) is stored –allantois—sac for disposal of waste –chorion—a membrane lining the inside of the shell which provides a surface for gas exchange during development Copulatory organs allow efficient internal fertilization

8. © 2006 Thomson-Brooks Cole

9. Physiological Adaptations Advanced circulatory system in which circulation through the lungs is nearly completely separate from circulation through the rest of the body –more efficient method of supplying oxygen Kidneys are efficient in eliminating wastes while conserving water Skin covered with scales and lacking glands decreases water loss

10. © 2006 Thomson-Brooks Cole Marine Crocodiles Best adapted to the marine environment is the Asian saltwater crocodile (Crocodylus porosus) Large animals (up to 6 m long) Feed mainly on fishes Drink salt water and eliminate excess salt through salt glands on their tongues Lives along the shore, where it nests

11. © 2006 Thomson-Brooks Cole Sea Turtles

12. © 2006 Thomson-Brooks Cole

18. Sea Turtles Adaptations to life at sea –protective shells that are fused to the skeleton and fill in the spaces between the vertebrae and ribs protect their bodies outer layer of shell composed of keratin inner layer composed of bone carapace—dorsal surface of the shell pastron—ventral surface of the shell –leatherback turtle lacks shell and has a thick hide containing small bony plates

19. © 2006 Thomson-Brooks Cole

20. Sea Turtles Adaptations to life at sea (continued) –shell is flattened, streamlined,d reduced in size and weight, for buoyancy/swimming –large fatty deposits beneath the skin and light, spongy bones add buoyancy –front limbs are modified into large flippers –back limbs are paddle shaped and used for steering and digging nests

21. © 2006 Thomson-Brooks Cole Sea Turtles Behavior –generally solitary, don’t interact –remain submerged while at sea; breathe air but can stay under water for as long as 3 hours –alternate between feeding and resting during the day –sleep on the bottom under rocks or coral

22. © 2006 Thomson-Brooks Cole Sea Turtles Feeding and nutrition –have a beak-like structure instead of teeth –green sea turtle is the only herbivore –leatherback sea turtles eat jellyfish pharynx is lined with sharp spines to hold slippery prey digestive system adapted to withstand stings –large amounts of salt consumed with food and water are eliminated as concentrated tears through salt glands above the eyes

23. © 2006 Thomson-Brooks Cole

24. Sea Turtles Reproduction –courtship – males court females before mating; males may compete for a female, or 1 female may mate with several males –nesting – females dig shallow pits on the beach, usually at night, and bury eggs –development and hatching temperature determines development time and sex ratio hatchlings rush for the safety of the sea after hatching

25. © 2006 Thomson-Brooks Cole

26. Sea Turtles Turtle migrations –females migrate from feeding grounds to the beaches where they were born to nest –green sea turtles feed on grasses in warm, shallow continental waters, but breed on remote islands some breed on a 2- or 3-year cycle –method for navigation over long distances is unknown

27. © 2006 Thomson-Brooks Cole Sea Turtles Sea turtles in danger –beach erosion –artificial lighting near nesting beaches –sea turtles are killed when trapped in fishing nests, especially those used for shrimpers turtle exclusion devices can reduce turtle mortality by as much as 95% when used for shrimp nets –turtles are hunted by humans for meat, eggs, leather and shells

28. © 2006 Thomson-Brooks Cole

29. Marine Iguana The marine iguana of the Galápagos Islands off Ecuador is the only marine lizard Most are black, but some are mottled red and black –dark coloration is thought to allow more absorption of heat energy –raising body temperature allows them to swim and feed in cold Pacific waters

30. © 2006 Thomson-Brooks Cole Marine Iguana Feeding and nutrition –herbivores with a short, heavy snout for grazing on dense mats of seaweed –swallow small stones to reduce buoyancy for feeding under water –excess salt from consumed seawater is extracted and excreted by specialized tear and nasal glands

31. © 2006 Thomson-Brooks Cole Marine Iguana Behaviors –good swimmers, using lateral undulations of the body and tail –each male occupies a small territory on the rocks, usually with 1 or 2 females –intruders or challengers are attacked when they enter the male’s territory fights between male iguanas rarely result in serious injury

32. © 2006 Thomson-Brooks Cole Sea Snakes Adaptations to life in the sea –scales are absent or greatly reduced for streamlining –tail is laterally compressed into a paddle –nostrils are higher on the head valves in the nostrils prevent water from entering when the snake is submerged –single lung reaches to the tail, and trachea is modified to act as an accessory lung by absorbing oxygen

33. © 2006 Thomson-Brooks Cole Sea Snakes Adaptations to life in the sea (cont.) –can exchange gases through the skin while under water –can lower metabolic rate to use less O 2 Feeding and nutrition –eat mainly fish and eels, sometimes eggs –most ambush prey and strike with venomous fangs –can swallow prey more than twice their diameter

34. © 2006 Thomson-Brooks Cole Sea Snakes Reproduction –3 oviparous species lay eggs on land –others are viviparous, with females retaining the eggs within their bodies until they hatch; young can swim at birth Sea snakes and humans –sea snake venom is toxic to humans –being timid, sea snakes rarely bite humans; people eat them in Japan

35. © 2006 Thomson-Brooks Cole Seabirds 250 of 8,500 bird species are adapted to live near or in the sea Seabirds feed in the sea Some spend months away from land, but all must return to land to breed Types of seabirds: –shorebirds –gulls and their relatives –pelicans and their relatives –tubenoses –penguins

36. © 2006 Thomson-Brooks Cole Adaptations for Flight Homeothermic—maintaining a constant body temperature Feathers aid in flight and insulate High rate of metabolism to supply energy for active flight/nervous system Strong muscles, quick responses, great deal of coordination Advanced respiratory system with 4- chambered heart Keen senses

37. © 2006 Thomson-Brooks Cole Adapting to Life in the Sea Large amounts of salt are consumed with food and salt water –salt glands above the eyes produce tears to remove excess salt –these tears have twice the salt concentration of seawater

38. © 2006 Thomson-Brooks Cole

39. Shorebirds Waders with long legs and thin, sharp bills used to feed on intertidal organisms Oystercatchers, curlews & turnstones –oystercatchers use long, blunt, vertically- flattened orange bills to slice through adductor muscles of bivalve molluscs –long-billed curlew uses its bill like a forceps to extract shellfish from burrows

40. © 2006 Thomson-Brooks Cole Shorebirds –heavyset turnstones use slightly upturned bills as crowbars to turn over stones, sticks and beach debris in search of food Plovers –have short, plump bodies with bills resembling a pigeon’s, and are shorter than other waders –have nests characteristic of waders, built in depressions or hollows on the ground

41. © 2006 Thomson-Brooks Cole Shorebirds Avocets, stilts, and sandpipers –avocets and stilts have very long legs, elongated necks, and slender bodies –avocets wade through shallow water, moving a partially opened beak from side to side through the water, to feed –stilts probe the mud for small animals (e.g. insects, crustaceans) with their bills –sociable sandpipers feed on small crustaceans and molluscs as the surf retreats

42. © 2006 Thomson-Brooks Cole Shorebirds Herons (e.g. egrets and bitterns) –most stand still and wait for prey to come in range to feed –some stalk prey or stir up the bottom to frighten prey into motion so it can be caught

43. © 2006 Thomson-Brooks Cole Gulls and their Relatives Gulls have webbed feet and oil glands to waterproof their feathers They are not true ocean-going birds, and do not stray far from land Have enormous appetites Are not very selective feeders Relatives of gulls include terns, skuas, jaeger birds, skimmers and alcids

44. © 2006 Thomson-Brooks Cole Gulls and their Relatives Gulls –herring gulls are the most widespread, and are vocal, gray and white, and travel in large groups –feeding noisy, aggressive, efficient predators and scavengers may drop prey with hard shells on rocks or parking lots to break the shell open highly successful at finding food and surviving

45. © 2006 Thomson-Brooks Cole Gulls and their Relatives Gulls (continued) –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, and remain in the nest until almost fully grown, camouflaged by speckled down chicks are vulnerable to predation by other animals and by other gulls

46. © 2006 Thomson-Brooks Cole Gulls and their Relatives Terns –small, graceful birds with brightly-colored and delicately-sculpted bills, forked tails –hunt by plunging into the water for fish and invertebrates; 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

47. © 2006 Thomson-Brooks Cole Gulls and their Relatives Skimmers (scissorbills) –small birds with pupils that are vertical slits and a flexible lower jaw protruding much farther than the upper bill –fly over water and use the lower bill to create ripples at the water’s surface that attract fish –fish are then collected by flying along the same path over the water a second time

48. © 2006 Thomson-Brooks Cole Gulls and their Relatives Alcids (e.g. auks, puffins, murres) –look like penguins but are related to gulls convergent evolution—similar selective pressures brought about similar adaptations in unrelated groups of animals ecological equivalents—different groups of animal that have evolved independently along the same lines in similar habitats, and therefore display similar adaptations –major difference is that alcids can fly

49. © 2006 Thomson-Brooks Cole

51. Gulls and their Relatives –nesting and reproduction alcids gather in dense, noisy colonies in the cliffs along the northern Atlantic and Pacific oceans in early spring 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, and swim out to sea alcid parents spend most of their time gathering food for hungry chicks adult puffins abruptly leave chicks to learn to swim and survive by themselves after 6 weeks of constant care

52. © 2006 Thomson-Brooks Cole Pelicans and their Relatives E.g., 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

53. © 2006 Thomson-Brooks Cole Pelicans and their Relatives Pelicans –large birds preferring warm latitudes and estuary, coastal and inland waters –require a large fish population to support colonies of large birds –feed just under the water’s surface using gular pouches as nets gular pouch—a sac of skin that hangs between the flexible bones of the bird’s lower mandible

54. © 2006 Thomson-Brooks Cole Pelicans and their Relatives Boobies –dive into the sea from 18-30 m up to fish –species lay differing numbers of eggs; this is thought to reflect the reliability of the food supply around where they nest Cormorants –swim along the surface scanning for fish, then plunge deep to pursue them –lacking oil glands, they must periodically dry their wings in order to fly

55. © 2006 Thomson-Brooks Cole Pelicans and their Relatives Cormorants (continued) –most are strong fliers, but the Galápagos Island species is flightless –guano cormorant of the coast of Peru valued for its guano (bird manure) Frigatebirds –lightweight body and near 2 m wingspan –lacking oil glands, they feed by skimming with their bills –pursue/attack other birds to steal prey

56. © 2006 Thomson-Brooks Cole

57. Tubenoses E.g. petrels, albatrosses, shearwaters Have obvious tubular nostrils on their beaks which join with large nasal cavities within the head Nasal glands secrete concentrated salt solution Stomachs contain a large gland that produces a yellow oil composed of liquefied fat and vitamin A, used for feeding hatchlings and defense

58. © 2006 Thomson-Brooks Cole Tubenoses Albatrosses –gliders with wings nearly 3.5 m long –most live in the Southern Hemisphere where winds circle the earth without encountering land –usually come to land only to breed –courtship displays precede mating –1 egg is incubated by both parents on a volcano-shaped nest, and the young are fed on stomach oil, then regurgitated fish

59. © 2006 Thomson-Brooks Cole Tubenoses Petrels –storm petrels are small birds with long legs with a characteristic, fluttering flight feed with legs extended and feet paddling rapidly just below the surface form long-term pair bonds for breeding –diving petrels resemble auks live only in the Southern Hemisphere in year- round cold water spot prey from the air, perform a headlong dive, and pursue prey by “flying” underwater

60. © 2006 Thomson-Brooks Cole Penguins Bird most adapted to marine lifestyle Awkward on land, but swift swimmers –flap their wings to swim –torpedo-shaped bodies are streamlined –flat, webbed feet are used for steering –leap from the water to breathe Eat fishes, squid and krill Eaten by leopard seals and killer whales

61. © 2006 Thomson-Brooks Cole Penguins Reproduction in Antarctic species –adelie penguins lay eggs in summer; emperor penguins in mid-winter –female emperor penguin lays 1 egg, which the male incubates for 2 months while she visits her feeding grounds egg sits on his feet, covered by a fold of skin male can feed the chick a secretion from his crop if it hatches before female’s return crop—a digestive organ that stores food before it is processed

62. © 2006 Thomson-Brooks Cole Penguins –female returns with food in her crop for the chick, and male can feed –both parents help to feed the chick once it reaches 6 weeks –by summer, the chick can feed itself, and is ready to enter the sea