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Vertebrate Biology

Vertebrate Biology. Lecture 26. Phylum Chordata. Subphylum Urochordata. Subphylum Cephalochordata. Subphylum Vertebrata. Agnathans Fish Sharks tetrapods. tunicates. lancets. Chordate Characteristics. Subphylum Urochordata. tunicate. Subphylum Urochordata. tunicate. Subphylum

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Vertebrate Biology

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  1. Vertebrate Biology Lecture 26

  2. Phylum Chordata Subphylum Urochordata Subphylum Cephalochordata Subphylum Vertebrata Agnathans Fish Sharks tetrapods tunicates lancets

  3. Chordate Characteristics

  4. Subphylum Urochordata tunicate

  5. Subphylum Urochordata tunicate

  6. Subphylum Cephalochordata lancet

  7. Subphylum Cephalochordata lancet

  8. Subphylum Vertebrata Class Agnatha Hagfish

  9. Subphylum Vertebrata Class Agnatha lamprey

  10. Subphylum Vertebrata Sharks, skates, rays Class Chondrichthyes

  11. Class Chondrichthyes Characteristics Sharks, skates, rays, chimera • Posses jaws with teeth, cartilaginous skeleton, paired fins • Scales (denticles) have same origin and composition as teeth • Possesses 5-7 gills • Spiral valve intestine • Ureoosmotic strategy • Lateral line • No swim bladder • Heterocercal tail • Relatively unchanged (480 mybp)

  12. Modern Sharks Feeding Types • Planktivores • Carnivores • Parasites

  13. planktivores Gill arch from basking shark

  14. carnivores

  15. Parasites Cookie cutter shark

  16. Ampullae of Lorenzeni pores Detects weak magnetic fields produced by other fish

  17. Ampullae of Lorenzeni

  18. Development Ovipary- eggs enclosed in capsule; eggs are laid and hatched outside the mother Ovovipary- give birth to young, eggs develop in uterus Vivipary- give birth to young, placental connection

  19. Antagonistic displays

  20. Attacks on Humans • Most occur in near shore waters • Follow food • Usually mistaken identification or territoriality • Spear fishing

  21. 4 methods to minimize the risk of encountering a shark • stay away from harbor entrances • avoid going in the water early in the morning and late at night • stay in a large group of people • if spearing fish, trail fish behind you

  22. Shark Finning Fins drying in Cape Town, S. Africa

  23. Shark Cartilage • Cartilage- prevents growth of blood vessels in tissue • In theory, if it prevents the growth of blood vessels in tumors, the tumors would stop growing. • Little solid evidence for ingesting over the counter capsules; they’re diluted with sugar or sterilized with ethylene oxide (a human carcinogen) • Experiments with selacchi, derived from shark cartilage 90 g/day “+” results and FDA approved • Also, harvesting sharks for unproven cure is detrimental to shark population

  24. Class Osteichthyes Characteristics • Posses jaws with teeth, bony skeleton, paired fins • 4 paired gill arches covered by operculum • Intestine- simple, no spiral valve • Swim bladder • Lateral line • Homocercal tail • Scales- cycloid, ctenoid

  25. Class Osteichthyes 680 species of fish in the islands' waters. About 30% of these fish are endemic to the area .

  26. Domino damsel Trigger (Humu) White mouthed morey Porcupine Dwarf moray Achilles tang trumpetfish

  27. Class Amphibia Characteristics • Cold blooded • Returns to water to breed • Metamorphosis • Some toxic • Estivation-dry and hot • Hibernation- cold 3,500 species

  28. Class Amphibia Mudpuppy (salamander) newt salamander Poison arrow frog Rana cancrivora Coqui

  29. Class Amphibia Metamorphosis

  30. Class Amphibia “Canaries in the coal mine” • Habitat destruction • Introduced species • Pollution • Pesticide use • Diseases • Over-harvesting • Climate change • Increased UV radiation

  31. Class Reptilia Characteristics • Cold blooded • Have scales • Amniotic egg • Dry skin • 3 chambered heart (except crocks) 6,500 species

  32. Marine Reptiles Some reinvaded the oceans, but still breathe air: Saltwater crocodile Sea snake Marine turtle Marine iguana

  33. Sea Snakes Yellow- bellied sea snake

  34. Sea Snakes • Diversity: • Laticodtidae- krates- 5 species (1 is fw in Solomon Islands) • Hydrophidae- 54 different species • All derived from Colubrid ancestor; colubrids evolved 40 mya; Laticotids evolved from colubrids 30 mya • Location: • Laticotids- live from east coast India to Japan and come to the tip of Cape York (Australia) • Hydrophiids- found from south tip of Africa to India to South East Asian Islands to Japan to north half of Australia • Habitat: • Primarily tropical; coastalestuaries, coral reefs, open sea; 33-36oC

  35. Sea Snakes • Behavior: Often schooling in aggregations; Not aggressive but human fatalities have occurred • Prey: Feed on small fish or squid, which are killed with powerful venom • Predators (few): sharks, snapper, grouper, crabs, saltwater crocodiles, raptors; they descend to escape • Venom: 2-10 times as toxic as that of a cobras

  36. Sea Snakes • Adaptations to life in the sea • Osmoregulation: skin is impermeable to salts; salts eliminated by sublingual gland • Developing a flattened paddle-shaped tail and a laterally compressed body. • Reduced metabolic rate and increased tolerance for low oxygen levels • Lungs- greatly enlarged; hydrostatic organ • Gaseous exchange - lungs and the skin.

  37. Sea Snakes • Reproduction: • Krates are oviparous and lay eggs on land • Hydrophiids are viviparous and produce young in the water • Not much known about breeding • However, olive sea snake breed in spring; seasonal courtship displays Banded sea krates forming mating group Olive Sea Snake

  38. Saltwater crocodiles • Largest living crocodilians: 6-7 m long • Eggs laid and incubated on land • Tropical and subtropical

  39. Marine Iguanas • Endemic to Galapagos islands • Herbivorous: graze on seaweeds • Salt-glands on nose to eliminate excess salt • Recently observed feeding on land for first time • They return to land to escape predators.

  40. Marine Turtles (Honu)

  41. Anatomy • Dorsal shell = carapace • Ventral shell = plastron • Head does not retract carapace plastron

  42. Anatomy Female Male

  43. Adaptation to salt water Lacrimal glands

  44. Egg tooth- used to chip away at shell Group effort to get out of nest- emerge at night (safer) and head towards brightest light Artificial lights- confuse hatchlings Turtle nest Cross section

  45. Predators

  46. Factors Affecting Green Sea Turtle Population Hawaii-100-350 nesting females French Frigate Shoals in the Northwest Hawaiian chain • Hunters • Fisheries • Marine Debris • Coastal Development and Habitat Degradation • Fibropapilloma

  47. Commercial Value • Meat • Eggs- nearly forbidden in all countries with nesting beaches • Soup • Jewelry • Leather Convention on International Trade in Endangered Species (CITES): turtle commerce prohibited in countries that signed agreement

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