Ancestors of these various animals re-invaded oceans after evolving adaptations to life on land. 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 They had to make a transition back to the ocean Four limbs  two limbs (flippers) Four limbs  two limbs (flippers) Lungs  lungs with modification to store oxygen Lungs  lungs with modification to store oxygen Dryer habitat  water - adaptations to osmoregulation Dryer habitat  water - adaptations to osmoregulation Marine Reptiles, Birds, Mammals – Fig. 9-1

Internal fertilization – External Development (ovoviviparous) Internal fertilization – External Development (ovoviviparous) Leathery shells decrease water loss Leathery shells decrease water loss Scales/dry skin – decreases water loss Scales/dry skin – decreases water loss Uric acid as a nitrogenous waste decreases water loss Uric acid as a nitrogenous waste decreases water loss Ectotherm/poikilotherm Ectotherm/poikilotherm Marine Reptiles

Sea Turtles

Carapace – shell fused to backbone Carapace – shell fused to backbone Legs modified into fins Legs modified into fins Can not retract head (land turtles can) Can not retract head (land turtles can) Usually only leave water every 2-4 years to lay eggs (mating occurs at sea) Usually only leave water every 2-4 years to lay eggs (mating occurs at sea) Females return to beaches from which they were born Females return to beaches from which they were born Migrate – navigate by wave motion & magnetic field of earth Migrate – navigate by wave motion & magnetic field of earth eggs laid in sand to incubate for 60 days (Fig. 9-2) eggs laid in sand to incubate for 60 days (Fig. 9-2) All nine species are endangered All nine species are endangered Sea Turtles

caretta/video-09b.html (loggerhead turtle laying eggs) caretta/video-09b.html (loggerhead turtle laying eggs) caretta/video-09b.html caretta/video-09b.html 1 (turtle covering nest) 1 (turtle covering nest) ature=related (turtle heading back to sea) ature=related (turtle heading back to sea) ature=related ature=related (sea turtles hatching) (sea turtles hatching) (TED) (TED) Sea Turtles

Totally marine Totally marine Most venomous but usually not aggressive Most venomous but usually not aggressive carnivores carnivores Sea Snakes – Fig. 9-4

opics_with_matt_zaller_episode_6/?source=playlist (sea snake) opics_with_matt_zaller_episode_6/?source=playlist (eagle catching sea snake) Sea Snakes – Fig. 9-4

Marine iguana – Galapagos Island – Fig. 9-5 Marine iguana – Galapagos Island – Fig. 9-5 Saltwater crocodile Saltwater crocodile Other Marine Reptiles

Live a large part of their life at sea Live a large part of their life at sea Feathers – aid in warmth & buoyancy, water proof Feathers – aid in warmth & buoyancy, water proof Endotherms/homeothermic Endotherms/homeothermic Nest on land Nest on land Webbed feet Webbed feet Seabirds

Wings modified to flippers/can not fly Wings modified to flippers/can not fly Heavier bones decrease buoyancy Heavier bones decrease buoyancy Streamlined bodies Streamlined bodies Except for Galapagos, all live in cold climates Except for Galapagos, all live in cold climates Fat decreases heat loss Fat decreases heat loss Eggs laid in winter in order to hatch during spring when prey is abundant Eggs laid in winter in order to hatch during spring when prey is abundant Parental responsibilities are shared Parental responsibilities are shared Penguins – Fig. 9-6a

Penguins

Penguins

(emperor penguin & leopard seal) (emperor penguin & leopard seal) Penguins

Tubelike nostrils/heavy bills – curved Fig. 9-7a Tubelike nostrils/heavy bills – curved Fig. 9-7a Spend extended period of time at sea Spend extended period of time at sea Great flyers Great flyers Salt glands to excrete excess salt Salt glands to excrete excess salt Turbernoses

Turbernoses

Webbing between all four toes Webbing between all four toes Pelicans

Largest variety of seabirds Largest variety of seabirds Gulls and Related Birds

Do not swim Do not swim Found along beaches and estuaries Found along beaches and estuaries Shorebirds

Viviparous – placenta Viviparous – placenta Endotherm; homeothermic Endotherm; homeothermic Hair, mammary glands produce milk Hair, mammary glands produce milk Larger brain than other vertebrates Larger brain than other vertebrates Do not give birth to a large number of young because a lot of parental involvement 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. Marine mammals followed different evolutionary paths and adapted to the marine environment in different ways. Marine Mammals

Evolved from terrestrial carnivore Evolved from terrestrial carnivore Paddle-shaped flippers for swimming Paddle-shaped flippers for swimming Breed and give birth on land 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) 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 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 Sea lions – rear flippers can move forward, have external ears; front flippers can be rotated backward for support Walrus - tusks Walrus - tusks Seals, Sea Lions, Walruses Order Pinnipedia

mals/mammals-animals/seals-and- manatees/walrus_cuddle.html (walrus mother and pup) mals/mammals-animals/seals-and- manatees/walrus_cuddle.html (walrus mother and pup) mals/mammals-animals/seals-and- manatees/walrus_cuddle.html mals/mammals-animals/seals-and- manatees/walrus_cuddle.html (monk seal) (monk seal) Seals, Sea Lions, Walruses Order Pinnipedia

Smallest marine mammal Smallest marine mammal Lacks blubber; insulates by air trapped in dense fur Lacks blubber; insulates by air trapped in dense fur Most of its time is spent in water including breeding & birth Most of its time is spent in water including breeding & birth ea-otter/enhydra- lutris/video-ne08a.html ea-otter/enhydra- lutris/video-ne08a.html ea-otter/enhydra- lutris/video-ne08a.html ea-otter/enhydra- lutris/video-ne08a.html Sea Otters Order Carnivora

One pair of front flippers but no rear flippers One pair of front flippers but no rear flippers Horizontal tail Horizontal tail Strict herbivores Strict herbivores One pup is born every 3 years One pup is born every 3 years Manatees & Dugongs – “Sea Cows” Order - Sirenia

mals/mammals-animals/seals-and- manatees/dugong.html (dugong) mals/mammals-animals/seals-and- manatees/dugong.html

Whales/Dolphins/Porpoises Order 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/Porpoises Order Cetacea Sperm Whale - toothed

Whales/Dol phins/Porpoises Order Cetacea Humpback Whale (filter feeder)

Whales/Dolphins/Porpoises Order Cetacea Blue Whale – filter feeder; largest animal

Whales/Dolphins/Porpoises Order 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/Porpoises Order 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). e%20dolphin/dolphinvsporpoise.htm (dolphin vs porpoise) e%20dolphin/dolphinvsporpoise.htm

Whales/Dolphins/Porpoises Order Cetacea mals/mammals-animals/whales/whale_sperm.html (sperm whale diving) mals/mammals-animals/whales/whale_sperm.html musculus/video-08.html (blue whale feeding) musculus/video-08.html (humpback whales feeding) oL_MINZyo&feature=related (spinner dolphin) oL_MINZyo&feature=related

Biology of Marine Mammals Swimming 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 Mammals Swimming and Diving Deep divers must be able to hold breath for extended period of time 90 % of O2 is exchanged during each breath (only % 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 Mammals Echolocation 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)

Biology of Marine Mammals Behavior 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 Mammals Behavior 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

Biology of Marine Mammals Behavior Posture/Movement Communications Indicate mood – Ex. Dolphins will open their mouth as a threat posture Tail slapping may be a warning signal 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 lated lated

Biology of Marine Mammals Behavior 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 ure=fvwrel (mass stranding) ure=fvwrel

Biology of Marine Mammals Migration 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 Mammals Reproduction 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 (beluga whale giving birth)