ch 34.txt

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ch 34.txt
2011-12-01 01:51:54

biology 101
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  1. Vertebrates
    • -have backbone
    • -varying enormously in characteristics, such as body mass
  2. Chordata
    • -chordates are bilateral
    • -belong to Deuterostomia
    • -includes echinoderms
  3. Notochord
    • -longitudinal, flexible rod located between the digestive tube and the nerve cord
    • -fluid-filled cells in stiff, fibrous tissue
    • -provide skeletal support = firm but flexible
    • -in humans, it is reduced to gelatinous disks in between the vertebrae
  4. Dorsal, Hollow Nerve Cord
    • -unique to chordates
    • -hollow; developed from a plate of ectoderm that rolls up located dorsal to the notochord
    • -develops into central nervous system: brain and spinal cord
  5. Pharyngeal slits or clefts
    • -alongside the pharynx, there are a series of grooves (clefts) that develop into slits that open up to the outside body
    • -slits allow water to enter the mouth and exit the body without going through the digestive tract
    • -function as suspension feeding devices
    • -function in gas exchange
    • -in tetrapods, they don't develop into slits; develop into ear and structures in head and neck
  6. muscular, post-anal tail
    -it helps propel many aquatic species in the water
  7. Lancelets (Cephalochordata)
    • -most basal group of living chordates; invertebrates
    • -larvae feed on plankton
    • -wriggles backward into the sand, with anterior end sticking up
    • -mucus secreted by slits removes tiny food particles from the water
    • -gas exchange occurs more over entire body
    • -serial arrangement of muscles allow it to contract side to side in swimming - evidence of segmentation
    • -muscle develops from blocks of mesoderm = somites
  8. Tunicates (Urochordates)
    • -4 characteristics of chordates in larvae
    • -swims until it finds substrate
    • -metamorphosis- disappearing chordate characteristics
    • -organs rotate 90 degrees
    • -incurrent siphon
    • -large atrium
    • -"sea squirts" = jet themselves from the excurrent siphon
    • -9 Hox genes
  9. Chordate evolution
    • -lancelets provide useful clues to these evolutionary changes
    • -they have slightly swollen tip ("brain") at the anterior end of dorsal nerve cord
    • -Hox genes that organize regions of the brain correspond themselves in small clusters of cells
    • -turnicates have a completely sequenced genome (special genes that determine organs such as the heart and thyroid)
    • -turnicates lack genes like long range nerve impulses
  10. craniates
    • -origin of head, dorsal nerve cord, eyes and sensory organs
    • -skull
    • -duplicated genes from the divergence sequence led to genetic complexity
  11. Neural crest
    • -a collection of cells that appear near the dorsal margins of the closing neural tube in an embryo
    • -these cells give rise to teeth, bones, cartilage in the skull, dermis of the face, neurons, and sensory capsules
    • -aquatic craniates: clefts evolved into slits = gills
    • -associated with pumping water through
    • -facilitates gas exchange
    • -higher metabolic rates, more muscles
    • -heart with 2 chambers; blood cells and hemoglobin
    • -kidneys
  12. origin of craniates
    • -Haikouella = resembled lancelet
    • -had brain, small eyes, and muscle segments
    • -respiratory gills, no skull or ear organs
    • -Myllokunmingia = had ear capsules, eye capsules, and skull
  13. Hagfish (Myxini)
    • -cartilage skull
    • -lack jaws and vertebrae
    • -keratin "teeth", segmented muscles
    • -secrete slime as protection from predators
  14. vertebrates are craniates that have a backbone
    • -capturing food
    • -avoiding being eaten
  15. Dlx Family
    • -a group of transcription factor genes
    • -nervous system, skeleton, skull, and backbone
    • -aquatic vertebrates acquired fins and more efficient gas exchange through gills
  16. Lampreys (Petromyzontida)
    • -most are parasites that clamp jawless mouths onto the flank of a fish
    • -ingest the blood
    • -resemble lancelets in larval state
    • -devastated the fish in the Great Lakes
    • -cartilage lacks collagen
    • -have a flexible sheath around notochord (different from hagfish)
  17. Conodonts
    • -soft-bodied vertebrates with prominent eyes
    • -barbed hooks at anterior of mouth; mineralized with calcium
    • -their abundance 300 mya that today their fossils are used in petroleum
  18. mineralization hypotheses
    • -mineralization was associated with a transition in feeding mechanisms
    • -may have begun in the mouth and later was incorporated into protective armor
    • -then skull
  19. gnathostomes
    • -jawed vertebrates
    • -sharks, ray-finned fish, lobe-finned fish, amphibians, reptiles and mammals
    • -enlarged forebrain (for sight and smell)
    • -in aquatic, lateral line system = organs form a row along each side of the body and are sensitive to vibrations
  20. gnathostome hypothesis
    • -jaws evolved by modification of the skeletal rods that had previously supported the anterior pharyngeal slits
    • -the gnathostome common ancestor underwent a duplicated Hox gene; entire genome duplicated
  21. gnathostome fossils
    • -survival: fins and tails allowed them to swim fast; jaws let them cut flesh
    • -placoderms
    • -extinct, "plate-skinned"
    • -acanthodians
  22. Chondrichthyans
    • -sharks, rays, and skates
    • -skeleton made of cartilage
    • -mineralized bone is derived characteristic
  23. sharks
    • -streamlined body with fins
    • -oil in the liver keeps them buoyant
    • -constant swimming keeps gas exchange
    • -when they spend time on the ocean floor, they use muscles to pump water
    • -spiral valve within intestine which increases surface area and prolongs passage of food
    • -sharp vision, no colors
    • -smell; sound is transmitted through the entire body
  24. shark reproduction
    • -oviparous = lay eggs that hatch outside of the mother's body
    • -ovoviviarous = they retain fertilized egg within the body, hatched within the uterus
    • -viviparous = young develops within the uterus and is fed through the placenta
    • -excretory and birth leads to cloaca and then released from one hole
  25. rays
    • -bottom dwellers
    • -whiplike tail
    • -eat mollusks and crustaceans
  26. osteichthyan
    • -ossified endoskeleton
    • -made of calcium phosphate
    • -the fish have 5 pairs of gills protected by an operculum
    • -swim bladder = buoyancy
    • -may have had lungs
    • -flattened bony scales
    • -glands secrete mucus that reduces drag
    • -most are oviparous
  27. ray-finned fish
    • -bony rays that support their fins
    • -big source of protein for us
    • -threats: over fishing cod, building dams block their migration patterns
  28. lobe-fins
    • -rod-shaped bones surrounded by a thick layer of muscle in their pectoral and pelvic fins
    • -coalacanths thought to be extinct
    • -lungfishes burrow when ponds shrink
    • -tetrapods
  29. Tetrapods
    • -have limbs
    • -there is a neck, pelvic girdle is fused to backbone
    • -no gills
    • -Tiktaalik - fins, gills, lungs, covered in scales, ribs, neck, front fin was a limb design
  30. Amphibians
    -salamanders, frogs, caecilians
  31. salamanders (urodela)
    • -walk with a side to side bend of the body
    • -paedomorphosis is common, axolotl retains larval features even when sexually mature
    • -larvae look like adult and are carnivores
  32. frogs (anura)
    • -powerful hind legs to jump
    • -toads are frogs with leathery skin
    • -stick their tongue out to get flies
    • -distasteful mucus secreted from the body
    • -poisonous species are brightly colored
  33. apodans (caecilians)
    • -legless, nearly blind, look like earthworms
    • -they lost their legs as adaptations
    • -larvae look like adult and are carnivores
  34. amphibians
    • -larval stage of frog is tadpole = lateral line system; herbivore
    • -metamorphosis = carnivore, gets legs, lungs, external eardrums
    • -some lack lungs and breath through skin
    • -lay eggs in water, they lack shells
    • -some carry eggs on their backs or in their mouths
    • -some are oviparous and viviparous
    • -males us vocals to attract mates
    • -they are dying out due to: disease from chytrid fungi, habitat loss, climate change and pollution
  35. amniotes
    • -reptiles and mammals
    • -amniotic egg which contains amnion, chorion, yolk sac, and allantois
    • -egg allowed the embryo to develop on land in its own private pond, reducing dependence to aqueous environments
    • -some have shells
    • -use ribcage to ventilate lungs, which is more efficient and may have led to less permeable skin
  36. amnion
    -functions as fluid-filled cavity that cushions mechanical shock
  37. yolk sac
    -stockpile of nutrients
  38. allantois
    -disposal sac for certain metabolic waste
  39. chorion
    -gas exchange membrane
  40. reptiles
    • -tuataras, lizards, snakes, turtles, crocodiles, birds
    • -have scales that are made of protein keratin
    • -scales protect from desiccation and abrasion
    • -fertilization occurs internally, some are viviparous
    • -cold-blooded comes actually from behavioral adaptations (basking and seeking shade)
    • -ectothermic = absorb heat, allows them to survive on less food
    • -birds are endothermic = maintain body temp through metabolic activity
  41. parareptiles
    • -large, stocky, quadrupedal herbivores
    • -some had plates on their skin
  42. diapsids
    -a pair of holes on each side of the skill behind the eye socket; muscles pass through this hole to connect to the jaw
  43. lepidosaurs
    • -a lineage of diapsids
    • -tuataras, lizards, and snakes
    • -mososaurs
  44. archosaurs
    • -lineage of diapsids
    • -crocodiles, pterosaurs, dinosaurs
  45. pterosaurs
    • -first tetrapods to show flight
    • -different from birds and bats = collagen membrane from hind leg to foreleg
    • -fed like birds
  46. dinosaurs
    • -bipeds and quadrupeds
    • -ornithschians were herbivores = tail clubs and horned crests
    • -most were ectothermic, some were endothermic
    • -social, and moved fast
  47. theropods
    • -long necked giants
    • -bipedal carnivores
    • -T Rex
  48. tuataras
    -threatened by rats in New Zealand
  49. lizards
    • -very diverse
    • -jaragua lizard = 16 mm small
    • -komodo dragon = hunts deer
  50. snakes
    • -some snakes maintain pelvic and limb bones = evidence of ancestry
    • -carnivores, acute chemical sensors
    • -sensitive to ground vibrations
    • -heat detecting organs that allow them to hunt at night
    • -flickering tongue fans odors to the smell organs
  51. turtles
    • -hard shell provides for defense
    • -earlier turtles could not retract their heads
    • -mechanism for retracting head evolved independently in 2 branches of turtles
    • -huge leatherbacks feed on jellies
  52. alligators and crocodiles
    • -breath air through upturned nose
    • -were small and then evolved bigger
  53. birds
    • -lack urinary bladder, females have one ovary = weight saving modifications
    • -toothless = trims weight in head
    • -wings = feathers made up of beta keratin
    • -flight enhances hunting and scavenging; ready escape
    • -endothermic; high metabolism to keep energy for flight
    • -efficient lungs with many little tubes that supply oxygen thoroughly
    • -acute eyesight
    • -internal fertilization, brooding until eggs are hatched
  54. flight evolution
    • -feathers may have enabled small dinosaurs to gain extra lift as they jumped
    • -they could have gained traction while running and flapping
    • -glided from tree to tree
  55. bird evolution
    • -evolved from theropods
    • -first bird = Archaeopteryx
  56. ratites
    • -flightless birds
    • -ostrich, rhea, kiwi, cassowary, and emu
    • -sternal keel is absent
    • -small pectoral muscles
  57. penguins
    • -have powerful pectoral muscles
    • -"fly" in the water
  58. hummingbird
    -unique: only bird to hover and fly backwards
  59. specialized beaks
    • -flamengos have filtered beaks
    • -parrots have crushing beaks
  60. mammals
    • -mammary glands produce milk
    • -hair
    • -fat layer to preserve heat
    • -endothermic
    • -efficient reps oratory and circulatory systems
    • -diaphragm
    • -long duration of parent care (like birds)
    • -larger brain (like birds)
    • -differentiated teeth
  61. synapsids
    • -mammals belong to this group
    • -distinct feature: single temporal fenestra = hole behind the eye sockets
    • -jaw muscle passes through the fenestra and anchor on your temple in humans
    • -remodeled jaw
    • -2 bones that were in the jaw, became incorporated into middle ear of mammals
  62. monotremes
    • -platypus
    • -echidnas (anteaters)
    • -lay eggs, lack nipples
  63. Marsupials
    • -opossums, kangaroos, and koalas
    • -higher metabolic rates
    • -have nipples, and give birth to live young
    • -have a placenta
    • -born early in its development; stay in marsupium pouch
  64. Eutherians
    • -complex placenta
    • -longer pregnancies
    • -deer mouse, mole, woodchuck, wolverine, flying squirrel
  65. primates
    • -lemurs, tarsiers, monkey, and apes
    • -hands and feet for grasping, flat nails
    • -skin ridges on fingers
    • -large brain, short jaw, flat face
    • -characteristics for tree-dwellers
    • -they have big toe widely separated
    • -opposable thumb for power grip
    • -enhanced depth perception with forward facing eyes
  66. anthropoids
    -monkeys, apes
  67. living primates
    -lemurs, tarsiers, lorises, bush babies
  68. monkeys
    • -new world monkeys are arboreal; have prehensile (spider and squirrel monkeys)
    • -old world monkeys are ground-dwelling and arboreal; lack prehensile tail (baboons, mandrils)
    • -separate adaptive radiations
  69. apes
    • -gorillas, orangutans, chimps, gibbons, humans
    • -diverged from old world monkeys
    • -long arms, short legs, no tail
    • -gorillas and chimps are highly social
    • -larger brain
  70. human
    • -upright and bipedal
    • -capable of behavioral differences (language, thought, etc)
    • -reduced jaws, shorter intestines
    • -1% difference in genes
  71. hominins
    • -sahelanthropus
    • -have shared characteristics to humans: reduced canine teeth, flat faces
    • -more upright
    • -foramen magnum is positioned under the skull
    • -earlier hominins were smaller and had smaller brains
  72. Australopiths
    • -walked upright, human hands and feet, teeth
    • -1/3 the size of todays brain
    • -between 4 and 2 mya
    • -Lucy, 4.2 mya
    • -long lower jaws, smaller brains
    • -paranthropus = sturdy skulls, powerful jaws, and large teeth
  73. bipedalism
    • -hypothesis: tree-dwelling hominins could no longer move through canopy, natural selection favored walking on ground
    • -they lived in mixed habitats
  74. tool use
    • -2.5 mya cut marks on animal bones as evidence of tool use
    • -used with stone tools
    • -first stone tool use = A. garhi
  75. homo habilis
    -larger brain, shorter jaw
  76. homo ergaster
    • -slender legs, hips, short and straight fingers
    • -weight difference in male and female became less
    • -means more pair-bonding, less competition for women
  77. homo erectus
    -first species to migrate out of africa
  78. Neanderthals
    • -brain equal to humans
    • -buried their dead
    • -made hunting tools
  79. homo sapiens
    • -h. floresiensis related more to h. erectus
    • -isolated islands made a physical shrinkage; dwarfism
    • -smaller brains may have resulted from reduced energy consumption
    • -h. sapiens may have driven neanderthals to extinction by competition