Ch. 6: Marine Vertebrates

Transcription

1 Ch. 6: Marine Vertebrates Birds Reptiles Horned Puffin Bony Fish Mammals Bottlenose Bony Fish, Cartilaginous Fish, Reptiles, Birds, Mammals Hawksbill Cartilaginous Fish Sheephead (male) Hammerhead

2 Subphylum Vertebrata Features All have chordate features + Notochord segmented into bony vertebrae Segmented skeletal muscles Closed circulatory system w/ O 2 transported by hemoglobin (in red blood cells) Muscle segments Brain & specialized sensory organs

3 Bilateral Symmetry Endoskeleton (cartilage, bone, or both) Vertebrate Types Likely Marine Likely Marine

4 Marine Fishes 50% of all living vertebrates Live in water, have fins & scales Gills for gas exchange (O 2 in, CO 2 out) Water & dissolved O 2 enter mouth & pumped over gills O 2 flows from gills into blood CO 2 flows out of blood to gills water O 2 & water in water CO 2 & water out

5 Marine Fishes Gill Arch supports 2 Gill filaments (large surface area) Active fish (Tuna): 10X more gill surface than body surface O 2 diffuses from lamellae to capillaries & bloodstream

6 Countercurrent Gas Exchange Water & blood flow in opposite directions Blood from body (low O 2, High CO 2 ) Water in lamellae (High O 2, low CO 2 ) O 2 & CO 2 move via Diffusion Some fish Highly efficient form can extract of gas exchange 85% of DO in water Highly efficient form of gas exchange Air breathers use ~25% if O2 Air breathers extract ~ 25%

7 Class Agnantha (Jawless Fish) Lampreys & hagfishes Most primitive of fishes Feed by suction (round, muscular mouth & rows of teeth) Cylindrical body (like eel, snake) Cartilagenous skeletons Lack paired fins Lamprey & scales Bore into fish & eat from inside out! Hagfish Scavengers Some parasitic

8 Class Chondrichthyes: Cartilagenous Fish Sharks, rays, chimeras Nearly all marine Cartilage skeleton, Paired fins Movable jaws with teeth Alive for ~280 million years w/ little change Hypo-osmotic body fluids (50% less salt than sea water)

9 Class Chondrichthyes: Hypo-osmotic body fluids (50% less salt than sea water) Fluids accumulate Urea (toxic) & trimethylamine oxide (protein) + salt Internal ion concentration = external NaCl concentration

10 Chimeras Temperate ocean floor Size: up to 2 meters Poisonous spine on front of dorsal fin (defense) Pacific Spookfish Rhinochimaera pacifica Males use claspers (internal fertilization) Lay leathery cased eggs Hydrolagus sp. Chimaera monstrosa

11 Flattened bodies Wing-like pectoral fins, fused with head Gill slits on underside, eyes on top of head Live on bottom Venomous spines w/ serrated barbs Stingrays Sting for defense Skates & Rays Skates: Lack whip-like tail & stinger Electric Rays: shock their prey Guitarfish: Spines, but no stinger

12 Skates & Rays Most are lie-and-wait predators Manta rays: pelagic, plankton eaters Ovoviviparous: eggs hatch inside female & are born alive Except for skates Lay eggs (mermaids purses): tendrils secure egg in algae

13 Sharks Nurse Fast swimming, predatory Most swim continuously (or drown): force water over gills (oily liver helps bouyancy) Some rest on bottom (nurse, horn sharks) Tiny, tooth-like scales (denticles) on skin Rows of teeth constantly replaced Bull

14 Horn sharks Up to 60 ft. (18m) Leopard Smoothhound Whale sharks Bamboo Hammerhead Whale & Basking Sharks Eat Plankton Basking To 40 ft. (12m) Swell shark

15 Shark Reproduction Internal fertilization Clasper (penis) 3 incubation strategies: 1. Oviparous: Lay eggs (leathery case, yolk) Ex: horn, swell shark 2. Ovoviviparous: Eggs hatch w/in Mom s reproductive tract, yolk & oviduct fluids nourish young, born alive (Ex: Dogfish) Swell shark egg Some Oophagus: 1 st hatched d eat siblings in oviduct (Ex: Makos, sand tiger)

16 Shark Reproduction 3. Viviparous (live birth): placental link between Mom & young (like mammals) Young born alive, fully functional EX: Hammerhead, bull, basking sharks

17 Shark Locomotion Fairly immobile pectoral fins Side to side movement of Heterocercal Caudal provides forward thrust & lift Flattened underside & pectorals aid lift No swim bladder (only oily liver) Thresher Bull

18 Why do Sharks have a bad reputation? 375 shark species: only 30 reported to ever attack a human (4 sp. killed a human) Only ~12 potentially dangerous if encountered 80% harmless Tiger Galeocerdo cuvier White Carcharodon carcharias Bull Carcharhinus leucas

19 Sport Humans kill ~ 1 million sharks for every human killed by a shark You re 30 times more likely to be killed by lightning than a shark! Meat Fear Shark Fin Soup Finning

20 Why Do Sharks Sometimes Attack Humans? 1. Misidentification Diver & surfer silhouettes resemble pinnipeds World Unprovoked Attacks ( ): 212 (61 fatal)

21 2. Sharks strike unfamiliar objects to test for food potential Decide a prey's palatability while in its mouth Prefer prey rich in energy (fat): marine mammals Spit out energy-poor prey (not fatty): Humans Yuck! Too skinny! Yum! Blubber!

22 Why Should We Protect Sharks? Apex predators: control prey populations & maintain ecological balance Part of complex food web: Feed on fish, shellfish & mammals Sick & dying Larger animals (whales, seals, tuna) that have few predators If removed, ecosystem balance is altered Blue

23 Class Osteichthyes (Bony fish) Skeleton at least partially made of bone Lighter = smaller body sizes 98% of all fishes (> 50% marine) Operculum: bony plates protect gills Most have scales protected by mucus Coelacanths & lungfishes 2 sub-classes Ray Fins eelpout Black seabass

24 Coelacanth 1st appear in fossil record (Devonian) ~400 million years ago (MYA) Thought extinct 60 MYA Fresh, dead specimen discovered 1938 Found in Indian Ocean below 100m Rocky caves, more active at night 1 st Discovered Coelacanth Order Teleost (Largest Rayfin Order): 90% of all fish 60% are marine South Africa Neutral Bouyancy (swim bladder), scales Hypo-osmotic body fluids 80kg (176 lb.) Avg. 2m (6.5 ft.) long

25 Order Teleost (Largest Rayfin Order): 90% of all fish 60% are marine Neutral Bouyancy (swim bladder), scales Hypo-osmotic body fluids Great camouflage Movable fins = controlled swimmers Bluefin Tuna Haddock Atlantic Mackerel

26 Summer Flounder Teleosts Swordfish Monkfish Scorpionfish: Sea Raven Adapted to Many Habitats Bay Anchovy

27 ptic Coloration untershading: k back, Light Belly mouflage & Body ucture varies Habitat Benthic Camouflage & Body Structure varies by Habitat Cryptic Coloration Pelagic Countershading: Dark back, Light belly

28 Body Plan Variety Sprinting (Long, thin): being sighted as chase prey Maneuvering: egg-shaped, long fins ( drag, but surface for fine adjustment Cruising: Large, streamlined body, packed with muscle Generalist

29 Swim Bladder Allows for Greater Maneuverability Shark s flat, rigid pectoral fins must provide lift Swim bladder provides buoyancy = fins free for other uses (break, turn, balance) No Swim Bladder

30 Caudal Type Helps Determine Speed Rounded fin produces a lot of drag: Slower fish w/ high maneuverability Forked & Lunate fins greatly drag: Fast, cruising fish (Marathon swimmers) Increasing Drag: resistance Dragto movement Decreasing Drag: resistance in a fluid to movement in a fluid Aspect Ratio (Ht./area)

31 Species Maintenance of Males Many species don t maintain equal # s of males as females One male may mate w/ multiple females Hermaphroditic species often produce males as needed CA Sheephead: CA Sheephead: Females Females become become males after males ~ age 8after ~ age 8 All individuals contribute to All individuals producing & carrying young contribute to producing & carrying young

32 Marine Tetrapods Four-limbed, air breathers (lungs) Reptiles, Birds, Mammals All have terrestrial ancestors Depend on sea for food & spend significant time in/on sea Hypo-osmotic body fluids

33 Class Reptilia Land reptiles that returned to Sea Ectothermic, lungs (air), scales Salt glands excrete excess salt Kidneys produce concentrated urine Most live in tropics or subtropics Sea Krait Green Sea Turtle Caymen

34 Marine Reptiles Sea Snakes (61 species, most highly venomous) Sea Turtles (7 sp.) Marine Iguana (1 sp.) Estuaries: snakes, caymens, alligators, crocodiles Loggerhead Marine Iguana Marine Crocodiles Marine Iguana: Endemic to Galapagos (found nowhere else)

35 Marine Iguana Endemic to Galapagos (found nowhere else) Eat marine algae Long claws to hang on rocks Wide tail acts like rudder

36 Live up to 80 yrs. Sea Turtles Tropical & subtropical Food: sea jellies, algae, crustaceans, molluscs Threatened: hunted (meat, shell, eggs); beach & nest destruction; tangled in nets; pollution; eat plastic (mistake for jellies) Hawksbill Loggerhead

37 Sea Turtles Lay Eggs on Beaches eggs Hatched Babies Must Return to the Sea

38 Egg-laying Marine Reptiles & Birds Most reptiles (not snakes), all birds Internal fertilization Egg Incubation: Fluid-filled sack w/ food, waste storage, gas exchange Surrounded by protective Gas Exchange shell (hard or leathery) Food Waste Storage Surrounded by protective shell (hard or leathery)

39 Class Aves (Birds) Front appendages adapted for flight Streamlined, insulated bodies (Feathers) Endotherms (Homeotherms) = warm blooded Flyers have light, hollow bones All lay eggs on land Salt excreting glands Oystercatcher Marine birds: feed in sea, some only return to land to breed

40 Marine Birds More diverse than reptiles or mammals Prey acquisition & bill shape determined by prey type Gulls & Terns Coastal Successful fishers & scavengers Shorebirds Estuaries, shore Fly underwater Eat fish & marine invertebrates Most migrate from northern (summer) breeding grounds TO Southern, winter grounds Rest & winter in estuaries

41 Gulls & Terns Coastal Successful fishers & scavengers Western Gull Heerman s Gull Skimmer Terns: plungedivers Adult Juvenile

42 Shorebirds Estuaries, shore Eat fish & marine invertebrates Most migrate from northern (summer) breeding grounds TO Southern, winter grounds Rest & winter in estuaries plover Curlew Dunlin surfbird Pacific Flyway Oystercatcher

43 Shorebird Beak Types Dependent on prey type & feeding location Minimize competition based on beak length Penguins & Allies (Puffins, auklets) Penguins: Can t Fly, Great Swimmers, Southern Hemisphere only Pelicans & Allies Long beaks feed in deeper water

44 Penguins & Allies Gentoo Puffin Penguins: Can t Fly Great Swimmers Southern Hemisphere only

45 Brown Pelican Endangered species in Calif. Pelicans & Allies Throat pouch Cormorants: Solid bones & oily feathers White Pelican Cooperative feeders Bad flyers, Great divers & swimmers

46 Jaegers Albatross: Great flyers Horrible at landing Tubenoses: Come on land only to breed Kleptoparasites Shearwater

47 Marine Mammals

48 Marine Mammal Characteristics 1. Large Brain 2. Internal fertilization 3. Live young (Viviparous) 4. Embryo nourished via a placenta 5. Young fed milk (mammary glands) 6. Endothermic (warm blooded) 7. Body hair 8. Specialized Teeth Stellar Sea Lion 9. Separate, external opening for reproductive tract

49 Marine Mammal Classification Class Mammalia: 3 Orders 3 Suborders Sub-order Pinnepedia (Order Carnivora) Evolved from land mammals Returned to sea 50 MYA

50 Order Carnivora N. Hemis. only Semi-aquatic Rely on sea ice Thick fur & blubber Sea Otter Sea Otter Pacific (Alaska to S. Calif.) Hunted to near extinction Polar Bear Dense fur, little blubber, air between fur & skin Eat lbs/day (25-30% of body wt.) Use tools to eat urchin, shellfish

51 Pinnipeds: Predators, Blubber, Breed on land Sea Lion Seal

52 More Pinnipeds! Elephant seal Walrus Stiff whiskers are feelers Eat benthic invertebrates

53 Order Sirenia Warm, shallow, tropical seas Herbivores, no pelvic limbs Severely Endangered Dugong Boat propellers kill & injure Manatee Elephant relatives!

54 Steller s Sea Cow: hunted to extinction in 30 years (1741) Cetaceans: Whales, Dolphins, Porpoises Baleen Whales Order: Mysticeti (Blue, finback, gray humpback, right, minke, sei) 2 Blowholes Baleen = fibrous protein (keratin) Strains Bering water: Sea plankton, krill, sm. Fish, & Aleutian benthic inverts. Toothed Islands Whales Order: Odontoceti (Sperm, pilot,

55 Cetaceans: Whales, Dolphins, Porpoises Baleen Whales Order: Mysticeti Blue, finback, gray humpback, minke, 2 Blowholes Baleen = fibrous protein (keratin) Strains water: plankton, krill, sm. Fish, benthic inverts. Toothed Whales Order: Odontoceti Sperm, orca, dolphin, porpoise, narwhale 1 Blowhole Peg Teeth Social (family pods) Beluga

56 Baleen Whales Toothed California Migration

57 Baleen Whales Fin Whale Communicate with low frequency Gray Whale sounds (songs). Humpback Humpback over very long distances. Gray Humpback Gray

58 Baleen: Filters zooplankton from water or invertebrates from mud Tongue pushes food to throat, excess water/mud spit out Gray whale Humpback

59 ~ 6,000 mi. each way (Dec-April) calving & breeding (Baja, Mexico) TO Summer feeding (Alaska & Siberia) East. Pacific Gray s Pop. (few 1000 to ~25,000) West. Pacific Pop. still endangered Gray Whale Migration Longest mammal migration!

60 Beluga Whale Orca Toothed Whales Orca Pod Common Dolphin Dall s Porpoise

61 Odontocetes (Toothed Whales) Attacking gray whale

62 Marine Mammal Diving Adaptations: Respiratory system collects/retains O 2 : 1.Excellent O 2 storage in blood (High [Myoglobin] + Hemoglobin) 2. Bradycardia: slows heart rate while underwater to conserve O 2 3.Collapse lungs when diving ( water pressure & Nitrogen gas buildup in blood) 4.Vasoconstriction: shunt blood to vital organs (brain, heart)

63 Mammal Oxygen Storage Lungs Blood Muscle

64 Vertebrate Sensory Capabilities Specialized sensory organs convert chemical, mechanical, electromagnetic stimuli into nerve impulses Sent to Brain 1. Chemoreception (smell, taste) Fish: little taste, excellent olfaction Tetrapods: Don t smell in water (stop breathing) Cetaceans: lost ability to smell

65 Vertebrate Sensory Capabilities 2. Electroreception (Ampullae of Lorenzini) sharks detect electrical fields of prey w/ pits in snout 3. Mechanoreception (Lateral Line System): Detect vibrations Small canals with receptors (hair cells) Detect predators, prey, schooling schooling Lateral Line 1 Big fish or many?

66 Vertebrate Sensory Capabilities 4. Sound Reception: Sound transmitted 5X faster in water than air Lateral line = feel sound vibrations Excellent Hearing Echolocation (toothed whales) Echolocation: Produce sounds (clicks) See 3D picture of environment Fat bodies in jaw transmit sound to mid-ear Detect food (type & Excellent Hearing Echolocation (toothed whales)

67 Echolocation: Produce sounds (clicks) See 3D picture of environment Detect food (type & size of prey) May stun prey Melon Bounce off prey Clicks emitted Sonar! Jaws receive reflected sound ears brain Fat-filled chamber