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Chapter 12 Marine Mammals

Chapter 12 Marine Mammals. Key Concepts. Mammals have a body covering of hair, maintain a constant warm body temperature, and nourish their young with milk produced by the mammary glands of the mother. Sea otters have thick coats of fur and feed on marine invertebrates near shore.

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Chapter 12 Marine Mammals

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  1. Chapter 12 Marine Mammals

  2. Key Concepts • Mammals have a body covering of hair, maintain a constant warm body temperature, and nourish their young with milk produced by the mammary glands of the mother. • Sea otters have thick coats of fur and feed on marine invertebrates near shore. • Polar bears feed mainly on seals and are top predators in arctic food chains.

  3. Key Concepts • Pinnipeds have limbs modified to form flippers, and are better adapted to life at sea than to life on land. • Sirenians are totally aquatic mammals that feed on a variety of aquatic vegetation. • Cetaceans have a fish-like body shape and are the mammals most suited to life in the sea.

  4. Key Concepts • Special physiological adaptations allow cetaceans to dive to great depths and to remain submerged for long periods. • Cetaceans are intelligent animals that display a range of behaviors for communication and investigating their environment. • Some cetaceans use echolocation to navigate, find prey, and avoid predators.

  5. Key Concepts • Baleen whales have plates of baleen instead of teeth and feed primarily on plankton, such as krill. • Toothed whales have teeth allowing them to feed on larger prey, primarily fish and squid, although killer whales will eat marine birds and mammals. • Dolphins are intelligent animals that are capable of learning and sophisticated intraspecies communication.

  6. Characteristics of Marine Mammals • Most have hair insulating body • Homeothermic • Mothers produce milk for their young • mammary glands • Placental mammals • Placenta • Parental investment • Feed at various trophic levels

  7. Sea Otters • Enhydra lutris; order Carnivora • Found from California coast to the Aleutian Islands • Short, erect ears • Dexterous 5-fingered forelimbs • Well-defined hind limbs with fin-like feet • Have thick fur with an air layer for insulation • Usually stay within a mile of shore • normally give birth to 1 pup on shoreline rocks, and it soon follows its mother into the sea

  8. Sea Otters

  9. Sea Otters • Eat nearly 25% of their weight in each day • sea urchins, molluscs, crustaceans, fish • Diurnal, gregarious, vocal and playful • Nearly hunted to extinction for fur

  10. The Fantastic Fur of Sea Otters • https://youtu.be/Zxqg_um1TXI • https://youtu.be/Uc7Ahp5--eE - use rock to open clam

  11. IQ#1 • Write down five general characteristics of marine mammals?

  12. Polar Bears • Ursus maritimus; order Carnivora • Top predators in Arctic food chains • Adult male may be ~3 meters and 725 kilograms • Live on shifting ice sheets and floes • Well adapted to cold environment • large body • black skin • dense layer of under-fur

  13. Polar Bears • Eats mostly seals https://youtu.be/0mgnf6t9VEc • In spring, males compete for available females • Give birth usually to 2 cubs each weighing 1 lbs • Climate change causing shrinkage of ice sheets • Considered endangered

  14. Polar Bear International • http://www.polarbearsinternational.org/ • Website holds info on current research and management actions being taken to protect polar bears and their habitat.

  15. Fight for Survival • https://www.livescience.com/64741-polar-bears-are-taking-back-russia.html • Starvation leads to an invasion

  16. IQ#2 • When we talk about global warming, why does the melting of ice pose a great concern for polar bear populations?

  17. VIDEO: Polar bears playing

  18. Reflection 3 Things Learned: 1. 2. 3. 3 Things Confused: 1. 2. 3. Develop 3 hypothesis to your confused questions

  19. Bellringer 3/7 • Draw and color a marine mammal and present 5 interesting facts • Will be graded upon completion and presentation

  20. Pinnipeds: Seals, Sea Lions, and Walruses • Order carnivora; Suborder Pinnipedia • seals, elephant seals, sea lions and walruses • Mate, give birth and molt on land • Eat fish, larger invertebrates • Predators - sharks, whales and humans

  21. No external ears Front and back flippers cannot rotate Figure 12-4b p319

  22. Pinniped Characteristics • 3 families: • eared seals (Otariidae) • true seals (Phocidae) • walruses (Odobenidae) • Eared seals have small external ears • True seals lack external ears

  23. External ear Rear flippers can rotate forward Front flippers can rotate backward Figure 12-4a p319

  24. Pinniped Characteristics • Spindle-shaped bodies • Many have thick layers of fat • Round head is carried on a distinct neck • Large brains, well-developed senses • 2 pairs of limbs are modified into flippers

  25. Swimming and Diving • Fast swimmers and expert divers • Adaptations for diving • exhale before diving • metabolism slows and heart rate decreases • blood is redistributed • Have much more oxygen in their muscles than humans

  26. Reproduction in Pinnipeds • Most congregate on well-established breeding beaches to mate/give birth • Some species are polygynous • Males arrive to establish territories • Females give birth to pups conceived the previous year, then mate again

  27. Reproduction in Pinnipeds • Gestation is about 1 year • Seasonal delayed implantation • Lactation period varies • coldest habitats = shortest lactation • nursing stresses the mother • some breed on pack ice, and must wean pups before it breaks up and becomes dangerous to the pups

  28. NOW! • Turn to pg 322 in your textbook and read the following article on Stellar sea lions. • Write a 1 pg summary of the reading that sheds light on the mystery of their disappearance. What do scientist know?

  29. Eared Seals • Sea lions • coarse coat of nothing but hair • highly social; congregate when on shore • Fur seals • distinguished by thick undercoats • coats are prized in the fur market

  30. Phocids, or True Seals • Forelimbs closer to the head and smaller than the hind limbs • less adapted to life on land • move on land by dragging their bodies • Most congregate during breeding season; Derpy-looking seal jk

  31. Phocids, or True Seals • Harbor seals are a familiar type • Harp seal pups have a white coat, and are thus prized in the fur market • Leopard seal is only phocid that eats homeothermic prey, penguins, sea birds and other seals make up bulk of diet • Elephant seals are the largest, and bulls have a unique proboscis that amplifies their roar and attracts mates

  32. Walruses • Lack external ears but have a distinct neck and hind limbs that can be used for walking on land • Can grow to 3 to 5 meters in length and weigh up to 1,364 kilograms • Canine teeth of males develop into tusks • Typical family group is 1 bull with up to 3 females and calves of various ages (polygynous)

  33. Walruses • Reproduction • 11-month gestation period • calves with the mother for 4 or 5 years • Found in the Arctic • Eat fishes, crustaceans, molluscs and echinoderms • Native people hunt them for meat, not tusks

  34. IQ#1 THINK!! • Recall, • How long is the gestation period of the seal? • How long is the gestation period of the walrus? • Why do you think the gestation period of a seal is longer than the gestation period of a walrus? • What factors could contribute to gestation length????? Genetic or environmental? Give examples!

  35. Sirens: Manatees and Dugongs • Order Sirenia (sirenians) • Now confined to coastal areas and estuaries of tropical seas • What are estuaries???? • Bodies, forelimbs, pelvis similar to whales • Completely aquatic, helpless on land • What does completely aquatic mean???? • Gentle and often trusting of humans • Vulnerable to injuries by people

  36. Dugongs • Strictly marine! • Live in coastal areas of Indian Ocean • Feed on shallow-water grasses • Distinguished from manatees by: • larger heads • shorter flippers • notched tail • Only one species • https://youtu.be/YProaycNpHE

  37. Manatees • Three species • Northern, Brazilian and African manatees • Inhabit both the sea and inland rivers and lakes—estuaries • Mate and give birth under water!! • male remains with female • female gives birth to 1 calf after 11 months gestation • Strict vegetarians– feed on seagrass and algae • Waste water pollution feeds algae blooms!! Aren’t their presence important??? • Motorboat propellers a great danger

  38. Evolution of Sirenians??? • Based on morphological traits, manatees are believed to share common ancestry with elephants.

  39. Manatees • https://youtu.be/M0DCNzwh4p4

  40. Steller’s Sea Cow • Extinct! Sorry…… • First recorded by Georg Wilhelm Steller (1742-1742) was rare at the time already • Furs Steller brought from the Commander Islands attracted hunters to return • Used Steller’s Sea Cow as a food source, and hunted the species to extinction • Hunters found the meat tasty and delicious and easy to obtain • Fossil evidence suggest sea cow had a wider range even before discovered in 1742

  41. History on Stellar Sea Cow • https://youtu.be/fVT-HGKovUs

  42. Bellringer 3/21 • List at least 3 differences between a manatee and a dugong.

  43.  Announcements: • Extra Credit Opportunity for the end-of the quarter: • Notebook Check– Participation, notes signed by Mrs. Cartamil , classwork, homework etc.. (needs to have all bell ringers from the beginning to the end of the quarter) (If notes are missing my initials you will not receive credit for notes) (needs to be organized w/ binder and dividers requested from the beginning of the school year)

  44. Bellringer 4/2 (15 mins) • Welcome back Marine Biologist!!  • Quickly, draw a specific type of cetacean and include 5 cool facts.

  45. NOW!!! Today, You will… 1. With your textbook, write notes from page 326, section 12-6 whale relatives thru general characteristics – this will be checked. (30mins) 2.Word Wall activity– draw/color a scenario from a vocab word and define. (20mins) 3. Lecture– introduction to cetaceans (15mins)

  46. AFascinationfor Cetaceans!

  47. What’s the origin???? • Fascinated by tribes Aboriginals, Polynesians, and Greek philosophers Phoecians • Unknown but thought to evolve from land-dwelling carnivores • Evidence includes from their evolutionary development– anatomy and fetus growth • Whale Fetus=land animals fetus • What do they have in common? • Well, let’s name a few… forelimbs, nostrils, front appendages with digits, eardrum

  48. Blowhole Tail fluke Present 0 Vestigial hip and thigh bones Vestigial pelvis Baleen whales Toothed whales, dolphins, and porpoises ? TIME (millions of years ago) 50 Semi-aquatic ancestor, Ambulocetus natans (extinct) Terrestrial ancestor (extinct) 55 Figure 12-10 p326

  49. General Characteristics of Cetaceans • Streamlined bodies closely resemble fishes • blowhole • blubber • lack of neck • internal ears with wax plugs • essentially hairless • no sweat glands • forelimbs modified into flippers • fluke - the main organ of propulsion • countercurrent circulatory system with cold blood directed to un-insulated flippers conserves heat

  50. Participation • Answer the following short answer questions: • IQ#1. List at least 5 general characteristics that cetaceans share? • IQ#2. How do evolutionary biologist speculate the origin of whales? What evidence is used to support their claim? • IQ#3. What similarities beside lungs do whales and land mammals share????

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