Marine Mammals, Birds and Reptiles

To the Land and Back  350 MYA - Tetrapods evolve from fish  Need:  Lungs  Forelimbs  Ability to avoid drying out  Some move back to the oceans - new adaptations required  350 MYA - Tetrapods evolve from fish  Need:  Lungs  Forelimbs  Ability to avoid drying out  Some move back to the oceans - new adaptations required

Sea Turtles  Enclosed by carapace  Cannot retract head  Flippers  Return to land to reproduce after long migrations  All threatened to endangered  Enclosed by carapace  Cannot retract head  Flippers  Return to land to reproduce after long migrations  All threatened to endangered

Sea Snakes

 Tropical Indian and Pacific  Laterally compressed  Ovoviparous  Small mouth but highly venomous

Marine Iguanas

 Galapagos  Live in large colonies  Herbivores  Salt glands in nose  Galapagos  Live in large colonies  Herbivores  Salt glands in nose

Saltwater Crocodile  Very large (usually max of 20 ft.)  Usually found in coastal areas  Highly aggressive  Very large (usually max of 20 ft.)  Usually found in coastal areas  Highly aggressive

Seabirds  Homeothermic / Endothermic  Oil glands  Feathers  Light, hollow bones  Hard egg shell But can they do this??!!

Penguins  Flightless  Denser bones (reduces buoyancy)  Layer of fat plus feathers for warmth  Southern hemisphere  Mating practices

Tubenoses

 Heavy curved beak  Mostly open sea predators  Elaborate courtship followed by lifelong pairing  Albatrosses, shearwaters, petrels  Heavy curved beak  Mostly open sea predators  Elaborate courtship followed by lifelong pairing  Albatrosses, shearwaters, petrels

Pelicans and Relatives  Webbing between toes  Fish eaters  Webbing between toes  Fish eaters

Gulls and Relatives

AUKS!!  Common name for the Alcids  May fill penguin niche in Northern Hemisphere  Puffins, razorbills, guillemots, dovekies (little auks)  Great auk extinct in 1844  Common name for the Alcids  May fill penguin niche in Northern Hemisphere  Puffins, razorbills, guillemots, dovekies (little auks)  Great auk extinct in 1844

Shorebirds  Herons, egrets, plovers, etc.  Found on coastlines usually for feeding  Often common in freshwater

Marine Mammals  Endothermic/Homeothermic  Hair and mammary glands  Viviparous and placental  Large, complex brain  Endothermic/Homeothermic  Hair and mammary glands  Viviparous and placental  Large, complex brain

Pinnipeds  Relatives of Carnivora  Blubber and fur  Seals, sea lions and walruses  Relatives of Carnivora  Blubber and fur  Seals, sea lions and walruses

Seals

Sea Lions and Fur Seals

Walruses

Carnivora - Polar Bears  Arctic top predators  Swim well but hunt on ice (seals, belugas, etc.)  Parental care  Arctic top predators  Swim well but hunt on ice (seals, belugas, etc.)  Parental care

Carnivora - Sea Otters  Smallest marine mammal  Lacks blubber but dense fur  Eat a LOT! (Mostly inverts)  Parental care  Still threatened

Sirenians  Manatees and dugongs  No rear limbs  Paddle shaped tail  Thick blubber layer but almost no hair  Four remaining species (all endangered)  Manatees and dugongs  No rear limbs  Paddle shaped tail  Thick blubber layer but almost no hair  Four remaining species (all endangered)

Cetaceans  Largest group of marine mammals  Entirely aquatic  Convergent evolution  Largest group of marine mammals  Entirely aquatic  Convergent evolution

Respiration  Nasal drift  Rapid air movement  90% oxygen delivery from lungs!  Blood adaptations:  Greater blood volume  More erythrocytes with more hemoglobin  Extra myoglobin in muscles  Lowered HR and restricted blood flow  Lung collapse?? Exhalation before diving?? Why??  Nasal drift  Rapid air movement  90% oxygen delivery from lungs!  Blood adaptations:  Greater blood volume  More erythrocytes with more hemoglobin  Extra myoglobin in muscles  Lowered HR and restricted blood flow  Lung collapse?? Exhalation before diving?? Why??

Echolocation  Toothed whales, some pinnipeds and baleen whales

It’s cold down there!!  Blubber - useful as insulation and as energy reserve  Fur in pinnipeds and carnivora  Blood vessels in whale tongues transfer heat back to core  Blubber - useful as insulation and as energy reserve  Fur in pinnipeds and carnivora  Blood vessels in whale tongues transfer heat back to core

Vocalization What purpose does it serve?

Other Behaviors

Reproduction - Cetaceans  Copulation in water  Competition and cooperation  Sex play  month gestation  Birth  Maternal care  Copulation in water  Competition and cooperation  Sex play  month gestation  Birth  Maternal care

Reproduction - Pinnipeds  Monogamy vs. polygamy  Harems and bachelor groups  Maternal care  Variation in nursing period  Females return  Delayed implantation allows birth to coincide with return to shore  Monogamy vs. polygamy  Harems and bachelor groups  Maternal care  Variation in nursing period  Females return  Delayed implantation allows birth to coincide with return to shore