Chapter 11 and 12

1. Chapter 11 and 12 Reptiles and Birds Marine Mammals

2. Marine Reptiles • Successful on land and in water • First began to appear about 100 million years ago • Modern day reptiles include crocodilians, turtles, lizards, and snakes.

3. Amniotic Egg • Major reason for the success of reptiles was the evolution of an amniotic egg • Covered by a protective shell and contains a liquid-filled sac called the amnion in which the embryo develops • Form of food comes from the yolk, stored in the yolk sac

5. Amniotic Egg • The allantios is designed to release waste • Membrane called the chorion lions the inside of the shell and provides a surface for gas exchange during development

6. Physiological Adaptations • The circulatory system of reptiles is more advanced than that of fishes • Circulation through the lungs is nearly completely separate from the circulation through the rest of the body • There kidneys are very efficient in the elimination of wastes and conservation of water • This allows them to inhabit dry regions and the salty environment of the ocean • Reptiles skin is covered in scales and generally lacks glands

7. Marine Crocodiles • Several species venture into the marine environment to feed. • American Crocodile • Nile Crocodile • Asian Saltwater Crocodile inhabits estuaries from India and Southeast Asia to Northern Australia

8. Saltwater Crocodiles • Can grow to 6 meters • Feed mainly on fish but have been known to attack an kill sharks • Very aggressive  can kill humans • Lives along the shoreline • Lays eggs on land

10. Sea Turtles • Seven species of sea turtles that inhabit the world’s oceans • Leatherback • Hawksbill • Kemp’s Ridley • Green • Loggerhead • Flatback • Olive Ridley

11. Adaptations to Sea Life • Have changed very little since they first evolved 150 million years ago • Covered with shells that are fused to the skeleton and fill in the spaces between the vertebrae and ribs

12. Turtle Shell • The dorsal surface of the turtle’s shell is a carapace • Ventral surface is the plastron • Leatherhead turtle lacks a shell, body is covered with a thick hide that contains small bony plates

13. Behavior • Generally solitary animals that remain submerged for most of the time they are in the sea • Alternate their time between feeding and resting during the day • Can stay underwater for up to three hours

14. Feeding and nutrition • Lack teeth but have a beaklike structure that they use to secure food • All but the green turtle they are carnivorous • Drink the salt water as they eat • Have special salt glands to rid themselves of the excess salt

15. Reproduction • Mate at sea • Males will court females by nuzzling their heads or nipping at their necks and flippers • If the female does not try to escape the male will grab shell and copulate. • Several males will fight for each female

16. Nesting and Hatching • Mainly occurs at night • Lay between 80-150 eggs • Male keeps the eggs moist by secreting a mucus on the eggs • Average incubation period is 60 days • Usually hatch at night and make their way to the ocean

17. Turtle Migration • Migrate hundreds and thousands miles from their feeding grounds to nest on beaches • Females always return to the same beach from which they were hatched to lay their eggs

18. How do they navigate • There are many hypothesis • Sense of smell • Taste • Audible signals • Magnetic field of the earth • Sun • The true reason is still unknown

20. Sea Turtles in Danger • Most species are endangered as a result of human activity • Beach erosion • Artificial lighting at nesting sites • Boat activity

21. Marine Iguana • The only marine lizard in is the iguana found on the Galapagos Island • Can grow up to 1 meter long • Herbivores • Good swimmers • Territorial

22. Sea Birds • 250 of the 8,500 bird species are adapted for life around the ocean • Homeothermic • They maintain a constant body temperature • Covered with feathers • High metabolism

23. Adaptation to the Sea • Salt glands • Located one above each eye • Excrete excess salt from their bodies • Shorebirds • Thin, long legs • Sharp bills

24. Types of Birds • Oyster catchers • Plovers • Sandpipers • Herons • Gulls • Skimmers • Skuas • Puffins • Pelicans • Boobies • Cormorants • Frigate birds • Tubenoses • penguins

25. Assignment • Pick 7 birds • Picture • How they reproduce • Nesting Habitats • How they Care for young • Where they live • What they eat • Not all the information can be found in the book for every bird. • Extra research may be necessary • Due Wednesday

26. Chapter 12 Marine Mammals

27. Characteristics of Marine Mammals • Insulation body covering of hair (most) • Homeothermic • Feed young with milk • Mammary glands • Placental mammals • Retain young inside body until they are ready to be born

28. Sea Otters • Skin is covered with thick fur with an underlying air layer that protects the animal form the cold • Short ears • Five-fingered forelimbs • Don’t go more then a mile from shore • Large appetite • Eat 25% of their body weight in food each day • Sea urchins • Molluscs • Fish • Often observed playing • Hunted for their fur

29. Pinnipeds: Seals, Sea Lions, and Walruses • Pinniped • Featherfooted • Retained forelimbs therefore are able to walk on land • Come on shore to give birth and molt • Most mate on shore • Many sleep on land to avoid predation • Three families • Otariidae • Eared seals • Phocidae • True seals • Obobenidae • walruses

30. Characteristics • Ears • Rear flippers • Front flippers • Spindle shaped body • Several thick layers of subcutaneous fat • Round head • Distinct neck • Allows independent movement of head • Large brains • Well developed senses • Vestigial tail

31. Swimming and Diving • Very fast • 15-18 miles per hour • For short distances • Can remain under water for as long as 45 minutes • Exhale prior to diving to decrease buoyancy • Underwater their metabolism slows to 20% and heart rate decreases to conserve oxygen • Some a capable of diving to great depths • Weddell Seal • 1,968 feet • 70 minutes

32. Reproduction • Most leave the water to reproduce • Congregate on beaches • Some species are polygynous • One male mates with several females • Females arrive ready to give birth, and conceive again • Gestation is 9-12 months depending on the species • Only 1-2 pups are born at a time • Cared for by the mother for 2-3 weeks

33. Eared Seals • Sea Lions • Intelligent • Eagerness to learn • Playful • Highly social • territorial • Fur Seals • Thick, woolly undercoats • Hunted • 1914 only 200,000 • Today 1.5 million • small

34. True Seals • Forelimbs set closer to the head and are smaller than hind limbs • Less adapted to life on land • Most abundant is the crabeater seal • 15 million • Most familiar is the Harbor Seal • Leopard Seal • Harp Seal

35. Walruses • Lack external ears • Distinct neck • Hind limbs allow them to walk on land • Very large • Tusks • Appear around 5 years and continue to grow • Hunted for their tusks

36. Sirens • At one time were widely distributed around the world • Now are confined to coastal areas and estuaries • No hind limbs • Vestigial pelvis

37. Sirens Manatees Dugongs Marine and coastal waters Feed on shallow-water grasses Tail in not notched • Live in sea and inland rivers • Mate and give birth underwater • Males remain with mates even after breeding season

38. Cetaceans • Best adapted for a marine life • Bodies closely resemble fish • Exact ancestry is not known • Believe to have evolved from land animals • Five fingered appendages • Vestigial pelvic bones • Blowhole for breathing • Streamlined body • Flippers • Tail fluk

39. Adaptations for Diving • Able to dive great depths • Alveoli • Numerous number of air sacs help to oxygenate the blood • Metabolism and heart rate decrease while diving • Contain hemoglobin within their red blood cells • Lactic acid is produced when oxygen levels are low • Creates a mucus coating in the lungs to prevent the bends

40. Cetacean Behaviors • Spy Hopping • Whales stick their heads straight up out of the water and survey their surroundings • Generally occurs when interested in a boat not another whale • Breaching • Whale completely or almost completely leaves the water • Social reasons • Slapping • Hitting fins on the waters surface • Marking position

41. Reproduction and Development • Most travel in groups called pods • Composed of adults and young • Bear only one offspring at a time • Feed young with milk • 40-50% fat • Care for young for several weeks

42. Baleen Whales Right Whales Rorquals Gray whales Toothed Whales Sperm whales White Whales Porpoises Dolphins Pick seven of the following and create a foldable, giving as much information about the whales as possible Must include pictures Must include specific characterists Types of Whales

43. Echolocation • Most whales can not see much farther than 100 feet even in clear water • They have ears that are modified to receive a wide range of underwater vibrations • Similar to SONAR • Allows animals to distinguish and home in on objects from distance of several hundred meters away

44. Echolocation • Arthur F. McBride • First to discover echolocation in cetaceans in the early 1950’s • Winthrop N. Kellogg • Demonstrated that dolphins use a series of clicking sounds in the same what that humans use sonar

45. Orientation Clicks Low-frequency clicks give the animals a general idea of its surroundings Discrimination clicks Give the animal a precise picture of a particular object Can be produced as a single sound or a series of sounds Dolphins Clicks

46. Does not have vocal cords Ring of muscles that acts as a valve Allows air flow through the valve Air under pressure circulates through the animals nasal passages and produce the clicks The Sound is directed by being focused in the melon Dolphin Larynx

47. Cont. • When the sound emitted bounces off the target and is picked up by sensors in the low jaw • The sound can only bounce of solid objects • Sound is only direct forward the animal • Can not sense anything below the jaw line • Such as sloping terrain

48. Can determine • Direction • Change in frequency • Amplitude • Time elapsed before the emitted sound returns • Size • Shape • Texture • density

49. Scanning the Ocean floor • Dolphins scan the ocean floor by emitting sound waves then move head side to side, up and down to get the vibrations back • This determines what they may attach or flea from