Characteristics of Tetrapods

Transcription

1 Marine Tetrapods

2 Characteristics of Tetrapods Tetrapod = four-footed Reptiles, Birds, & Mammals No marine species of amphibian Air-breathing lungs

3 Class Reptilia Saltwater Crocodiles, Sea turtles, sea snakes, marine iguanas Shared Characteristics: Cold-blooded Live in tropical areas Ectotherms = temperature varies with surroundings Oviparous internally fertilized eggs Sea snakes are ovoviviparous Scales

4 Crocodiles, Sea Snakes & Iguanas Order Crocodilia Semi-aquatic Estuaries Giant saltwater crocodile Order Squamata (snakes & lizards) Sea snake - 61 species All breathe air, but some species can absorb oxygen from the water Most toxic venom of any snake Marine Iguana Galapagos Islands Herbivores

5 Order Chelonia 7 species of Sea turtles all endangered or threatened By-catch Bodies enclosed by shell Fused to backbone Legs modified into flippers No teeth strong jaws Herbivores Return to land to reproduce Males fertilize eggs in the water Females lay eggs & bury them on beaches Eggs hatch after about 60 days

6 Class Aves - Birds Warm-blooded Homeotherms = stable internal temperature Endotherms Oviparous Care for young Many mate for life Waterproof feathers Oil gland above base of tail Hollow bones Feet & legs are adapted for lifestyle Seabirds = webbed feet Shorebirds = non-webbed feet Penguins, Albatross, Pelicans, Gulls, shorebirds

7 Penguins Order Sphenisciformes Flightless All live in the Southern Hemisphere 80% of the birds in Antarctica are penguins South America, Africa, Australia, New Zealand, Galapagos Islands Adapted to water Wings modified as flippers for swimming Bones are more dense Reduces buoyancy Eyes adapted for underwater vision Nearsighted Breeding Most species breed on subarctic islands Emperor penguins stay on Antarctica

8 Mammals Homeotherms Hair helps to retain heat Viviparous eggs develop internally and receive nutrients & oxygen from mother Mammary glands feed newborns Produce few, but well-cared-for young seals, polar bears, manatees, whales

9 Challenges for Marine Mammals High oxygen consumption Life in the water requires more energy, so more oxygen is needed Maintaining temperature Breathing air Breathing air provides more oxygen myoglobin similar, but more efficient than hemoglobin Mammalian diving reflex pulse & blood flow slows

10 Challenges for Marine Mammals, cont. Water pressure Flexible lungs & sinuses Water density Moving through water requires more energy Streamlined bodies Skin adaptations Senses Sensitive hearing Echolocation

11 Order Pinnipedia Seals, Sea Lions, & Walrusses Paddle-shaped flippers Seals no ear flaps & rear flippers point backward Sea lions - ear flaps & can rotate rear flippers Walrusses - no ear flaps & can rotate rear flippers Rest & breed on land Live in cold waters Blubber = thick layer of fat Maintains body heat Serves as food storage Helps provide buoyancy

12 Order Carnivora Sea otter Smallest marine mammal Dense fur Lack blubber Spend most or all of life in water Polar bears Semiaquatic Live on arctic coasts & floating ice

13 Order Sirenia Manatees & dugongs (sea cows) Manatees are relatives of elephants Rare and endangered Paired front flippers No rear limbs paddle shaped tail Gentle animals The only herbivorous marine mammals Live in groups Reproduce slowly Every 3 years

14 Order Cetacea Whales, dolphins, and porpoises Streamlined bodies Blubber Fish-like body Paired front flippers, dorsal fin & tail Blowhole = nostrils Two groups of whales: Baleen (suborder Mysticeti) Toothed (suborder Odontoceti) Echolocation

15 Echolocation Used by most toothed whales Hunting Natural sonar Emit sound waves & listen for echoes Melon = fatty structure on forehead used to direct outgoing sound waves Incoming sound waves detected by the lower jaw

16 Baleen whales Baleen = rows of flexible, fibrous plates that hang from the upper jaw Feeding: Mouthful of water Squeeze water out through baleen Use tongue to lick off food Blue whale = largest animal on earth Record female 110 ft long, 200 tons