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Marine Reptiles

Explore the evolution of marine reptiles from ocean origins to land adaptation. Discover the unique characteristics of reptiles such as crocodiles, turtles, and sea snakes. Learn about the challenges they face and how human interactions impact their survival. Dive into the fascinating world of these ancient creatures!

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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

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