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Marine Reptiles, Birds, Mammals. Marine Reptiles, Birds, Mammals – Fig. 9-1. Ancestors of these various animals re-invaded oceans after evolving adaptations to life on land. They had to make a transition back to the ocean Four limbs two limbs (flippers)
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Marine Reptiles, Birds, Mammals – Fig. 9-1 • Ancestors of these various animals re-invaded oceans after evolving adaptations to life on land. • They had to make a transition back to the ocean • Four limbs two limbs (flippers) • Lungs lungs with modification to store oxygen • Dryer habitat water - adaptations to osmoregulation
Marine Reptiles • Internal fertilization – External Development (ovoviviparous) • Leathery shells decrease water loss • Scales/dry skin – decreases water loss • Uric acid as a nitrogenous waste decreases water loss • Ectotherm/poikilotherm
Sea Turtles • Carapace – shell fused to backbone • Legs modified into fins • Can not retract head (land turtles can) • Usually only leave water every 2-4 years to lay eggs (mating occurs at sea) • Females return to beaches from which they were born • Migrate – navigate by wave motion & magnetic field of earth • 100-160 eggs laid in sand to incubate for 60 days (Fig. 9-2) • All nine species are endangered
Sea Turtles • http://www.arkive.org/loggerhead-turtle/caretta-caretta/video-09b.html (loggerhead turtle laying eggs) • http://www.youtube.com/watch?v=TYX0Kt73li8&NR=1 (turtle covering nest) • http://www.youtube.com/watch?v=fH9nNDdFh4w&feature=related (turtle heading back to sea) • http://www.youtube.com/watch?v=0TbzP0AT1Bk (sea turtles hatching) • http://www.youtube.com/watch?v=j9olIycYg0c (TED)
Sea Snakes – Fig. 9-4 • Totally marine • Most venomous but usually not aggressive • carnivores
Sea Snakes – Fig. 9-4 • http://www.metacafe.com/watch/6192859/trending_topics_with_matt_zaller_episode_6/?source=playlist (sea snake) • http://www.youtube.com/watch?v=Xf240LcsPno (eagle catching sea snake)
Other Marine Reptiles • Marine iguana – Galapagos Island – Fig. 9-5 • Saltwater crocodile
Seabirds • Live a large part of their life at sea • Feathers – aid in warmth & buoyancy , water proof • Endotherms/homeothermic • Nest on land • Webbed feet
Penguins – Fig. 9-6a • Wings modified to flippers/can not fly • Heavier bones decrease buoyancy • Streamlined bodies • Except for Galapagos, all live in cold climates • Fat decreases heat loss • Eggs laid in winter in order to hatch during spring when prey is abundant • Parental responsibilities are shared
Penguins • http://www.youtube.com/watch?v=r3RElQWsh34 (emperor penguin & leopard seal)
Turbernoses • Tubelike nostrils/heavy bills – curved Fig. 9-7a • Spend extended period of time at sea • Great flyers • Salt glands to excrete excess salt
Pelicans • Webbing between all four toes
Gulls and Related Birds • Largest variety of seabirds
Shorebirds • Do not swim • Found along beaches and estuaries
Marine Mammals • Viviparous – placenta • Endotherm; homeothermic • Hair, mammary glands produce milk • Larger brain than other vertebrates • Do not give birth to a large number of young because a lot of parental involvement • Marine mammals followed different evolutionary paths and adapted to the marine environment in different ways.
Seals, Sea Lions, WalrusesOrder Pinnipedia • Evolved from terrestrial carnivore • Paddle-shaped flippers for swimming • Breed and give birth on land • Blubber – insulates, serves a food reserve and aids in buoyancy (large body size also serves to decrease heat loss because of a decrease in the surface area to volume ratio) • Seals – rear flippers can not move forward, have internal ears • Sea lions – rear flippers can move forward, have external ears; front flippers can be rotated backward for support • Walrus - tusks
Seals, Sea Lions, WalrusesOrder Pinnipedia • http://video.nationalgeographic.com/video/player/animals/mammals-animals/seals-and-manatees/walrus_cuddle.html (walrus mother and pup) • http://www.youtube.com/watch?v=9PKDbJ-0gzs (monk seal)
Sea OttersOrder Carnivora • Smallest marine mammal • Lacks blubber; insulates by air trapped in dense fur • Most of its time is spent in water including breeding & birth • http://www.arkive.org/sea-otter/enhydra-lutris/video-ne08a.html
Manatees & Dugongs – “Sea Cows”Order - Sirenia • One pair of front flippers but no rear flippers • Horizontal tail • Strict herbivores • One pup is born every 3 years
Manatees & Dugongs – “Sea Cows”Order - Sirenia • http://video.nationalgeographic.com/video/player/animals/mammals-animals/seals-and-manatees/dugong.html (dugong)
Whales/Dolphins/PorpoisesOrder Cetacea • Largest group of marine mammals • Spend entire life at sea • Convergent evolution – different species develop similar characteristics because of environmental pressures. This is achieved through natural selection • Paired anterior fins (posterior present in embryo only) • Flukes – tail • Blubber • Baleen – fibrous plates that filters food from the water • Baleen whales have two blowholes • Toothed whales swallow food whole; have only one blowhole
Whales/Dolphins/PorpoisesOrder Cetacea Sperm Whale - toothed
Whales/Dolphins/PorpoisesOrder Cetacea Humpback Whale (filter feeder)
Whales/Dolphins/PorpoisesOrder Cetacea Blue Whale – filter feeder; largest animal
Whales/Dolphins/PorpoisesOrder Cetacea • Differences between dolphins and porpoises • Porpoises have flattened, spade-shaped teeth. • Another difference between these two similar creatures is their lengths. Dolphins have an extremely wide range of lengths and widths, anywhere from 1.2 meters (4 ft) and 40 kilograms 88 pounds up to 9.5 meters (30 ft) and ten tons, referring to the killer whale. While the stubbly porpoise’s average length is just over 5 ft (1.5m) while females are slightly larger with average lengths of 5.5 ft (1.7m).
Whales/Dolphins/PorpoisesOrder Cetacea • Finally the most visible and easily spotted difference between these two mammals, their physical make up, the dolphins posses conical teeth and shorter beaks, while the porpoises generally tend to have flattened, spade shape teeth, the name porpoise in actuality was named from medieval times, porcopiscus (porcus pig + piscus fish). • http://library.thinkquest.org/J0110164/Life%20of%20the%20dolphin/dolphinvsporpoise.htm (dolphin vs porpoise)
Whales/Dolphins/PorpoisesOrder Cetacea • http://video.nationalgeographic.com/video/player/animals/mammals-animals/whales/whale_sperm.html (sperm whale diving) • http://arkive.org/blue-whale/balaenoptera-musculus/video-08.html (blue whale feeding) • http://www.youtube.com/watch?v=vJvfjiCTvq4 (humpback whales feeding) • http://www.youtube.com/watch?v=7-oL_MINZyo&feature=related (spinner dolphin)
Biology of Marine MammalsSwimming and Diving • Streamlined bodies a must • Cetaceans move in an up and down motion • All other marine mammals paddle • Take quick breaths to avoid inhaling water (Cetaceans have blowhole on top to prevent this; can eat and breath at the same time)
Biology of Marine MammalsSwimming and Diving • Deep divers must be able to hold breath for extended period of time • 90 % of O2 is exchanged during each breath (only 10-20% in humans) • Have more blood with higher concentration of RBC’s, therefore can carry more O2 • Muscles rich in protein myoglobin (stores O2) • Reduce O2 consumption by slowing heart rate; reducing blood flow to extremities & gut • Adaptations to prevent N2 from dissolving in blood; Lungs collapse & air is squeezed out – air is moved to central spaces where little nitrogen is absorbed
Biology of Marine MammalsEcholocation • Echolocation is the ability to sense surrounding by analyzing the reflection of sound waves, or “clicks”. Used to find prey and orientation • Clicks produced by pushing air through nasal passages • Clicks focused and directed into a beam by melon (fatty structure found in toothed whales) • Clicks are reflected back & received by lower jaw • Sound transmitted to inner ear • Electrical stimulus is sent to brain & interpreted (forms a mental image) • http://www.youtube.com/watch?v=ZoNDW0zSRNo
Biology of Marine MammalsBehavior • Behavior – What an animal does and how it does it; results from both genes and environmental factors. Mammals exhibit more complex behaviors in which learning dominates over instinct
Biology of Marine MammalsBehavior • Vocal Communications – barks, grunts, whistles – species specific • Maintain territories • Recognize young or one another • Cetacean vocalization uses different types of sounds than echolocation • Reflect mood • Sexual signaling • Maintain distance between individuals • Warning • http://www.youtube.com/watch?v=v8b_I5IjNE4
Biology of Marine MammalsBehavior • Posture/Movement Communications • Indicate mood – Ex. Dolphins will open their mouth as a threat posture • Tail slapping may be a warning signal • http://www.youtube.com/watch?v=vv2VjaOK2iA • Play behavior – “just for fun” activities with no apparent goals • Dolphins will play with floating objects, “bow” ride • Breaching – warning signal; scanning surface; get rid of external parasites or maybe just for fun • Spy hopping – scanning surface (possibly used to recognize landmarks in migration http://www.youtube.com/watch?v=XLR8YkTEI1g&feature=related
Biology of Marine MammalsBehavior • Posture/Movement Communications • Mutual assistance • Assist others when in trouble • Enhances feeding • “scout” report • Stranding/beaching – mystery; may become disoriented by storm, illness or injury; healthy individuals may follow • http://www.youtube.com/watch?v=ezzmkEQILO0&feature=fvwrel (mass stranding)
Biology of Marine MammalsMigration • Migration – usually from feeding summer areas to winter breeding area • Baleen whales tend to migrate more than toothed whales • Use landmarks • Earth’s magnetic filed • May use current, temperature differences, or day length
Biology of Marine MammalsReproduction • To keep body streamlined most male marine mammals have internal reproductive structures • Some form harems – one male and many females (“left out” males form bachelor groups) • Pinnepeds – embryo remains dormant (delayed implantation) and is not attached to uterine wall; therefore pups will not be born to early in the water (gestation is only 8 months) • Calves of cetaceans born tail first to prevent drowning • http://www.youtube.com/watch?v=GyClkrV4dI4 (beluga whale giving birth)