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