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Marine Reptiles
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  1. Marine Reptiles

  2. The first vertebrates originated in the ocean • About 350 million years ago, • vertebrates came onto land • Descended from bony fishes

  3. (350 MYA) (285 MYA) (200 MYA)

  4. Harsher conditions ashore: • -no more water for support • -developed new ways to move • All land vertebrates evolved two pairs of limbs • Called tetrapods: “four-footed”(even snakes) • Evolved lungs & ways to stay moist

  5. General Characteristics of Class Reptilia • Dry scaly skin to protect against water loss • Lay eggs • Sex is determined by the temperature of the environment at a time during develop. • Ectothermic • Body temperature is regulated by environment and behavior • Basking in sunlight to warm and swimming to cool off • Limited to tropical and subtropical habitats

  6. Adaptations of Reptiles to Land • Lungs for breathing so cannot obtain oxygen from water • Amniotic egg-large yolk to nourish its young and a leathery shell to prevent dessication • Internal fertilization and eggs laid on land • 3 or 4 chambered hearts (more efficient at circulating oxygenated blood)

  7. Adaptations of Reptiles to Land • Salt glands- remove salt from their blood • Found above eyes • Salt excretions help conserve water and wash sand form their eyes • Concentrated urine to conserve water

  8. Order Crocodilia • Most advanced of all reptiles • Female lays eggs in a nest and provides limited care for its young for several wks • Eyes and nostrils are positioned to be above water while croc is submerged • Well developed senses (but cannot see underwater) • Opportunistic predators (carnivorous) • Food is mostly stored as fat and they can go years without a meal

  9. Order Squamata- snakes • All species of sea snake are venomous • 1 to 2 meters in length • Flattened body side to side and paddle tail aid in swimming • Some have live birth others must lay eggs on land • Lungs are highly inflatable and they can dive for 2 hours

  10. Order Squamata- Iguana • Amblyrhynchussubcristatus • Live on the Galapagos Islands southwest of South America • Dive in cold water to find algae to eat • Warm up by basking in sun • Remove salt w/ salt glands • Under threat by human introduced animals like cats, dogs and rats and human pollution

  11. Order Chelonia • Sea turtles are the most widely distributed reptile • All species are endangered

  12. Order Chelonia Sea Turtles

  13. Biology • Found year round in the tropics but higher latitude in the summer • Most feed in shallow water • Long migrations between feeding and breeding grounds • Males spend entire life at sea, females return to land to lay eggs • Nest every other year and a couple of times a season

  14. Life Cycle • 50-170 eggs , 6-13 weeks to hatch • Emergence is typically at dusk and hatchlings head towards the brightest horizon • Lost years- lead largely pelagic existence • Females return to natal breeding ground • Live more than 50 yrs, repro. between 10 and 30 yr old

  15. Sea Turtle Body Plan • Differ in size, pattern of scales on the shell • Sea turtles can survive up to 200 yrs • Body plan is well adapted to marine environment • Fatty deposits for buoyancy • Light bones for buoyancy • Streamlined shells and flippers • Dive up to 40 minutes

  16. LeatherbackDermochelyscoriacea • 6 ft long • Feed on jellyfish

  17. GreenChelonia midas • 3.3 ft • Juveniles eat molluscs, crustaceans and jellyfish • Adults eat seagrass and algae

  18. LoggerheadCarettacaretta • 3 ft long • Eat benthic crustaceans and molluscs

  19. HawksbillEretmochelysimbricata • 2-3 ft long • Eat sponges and benthic invertebrates

  20. Kemp’s RidleyLepidochelyskempii • 2-2.6 ft long • Eat crabs, shrimp and molluscs

  21. Sea Turtle Nesting Behavior • Use their flippers to dig a hole once they select a nesting site • Eggs are laid into the hole and covered with sand • 2 months later the eggs hatch • Between hatching and 20 years of age are the lost years

  22. Hatching Success • Nests with temps below 28.7 produce mostly males • At risk for predation • Risk of suffocation • Risk of drowning • 80% Hatch success rate • Only 1 or 2 turtles survive to maturity

  23. Human Interactions • Developing and building on the shoreline • Commercial fishing • Erosion of shoreline • Disturbing nesting beaches

  24. 4 • 5