BIOL111 Lectures 1-2

  1. What are the "big three" things biologists think an organism needs to be considered alive?
    • 1. Energy transformation - transform energy to synthesize new molecules
    • 2. Reproduce - make nearly faithful copies of themselves
    • 3. Maintain homeostasis - regulate internal environment in response to external changes
  2. What sources of energy are used by life?
    • 1. light
    • 2. inorganic compounds (H2, H2S etc.)
    • 3. organic compounds (starch, fats etc.)
  3. Define autotroph
    • "self-feeding"
    • can make organic molecules usig inorganic compounds and outside energy
  4. Define photoautotroph
    use light energy and CO2 to make glucose
  5. Define chemoautotroph
    use chemical energy and CO2 to make glucose
  6. Define heterotroph
    "different feeding"
  7. Define chemoheterotroph
    • consume organic molecules as both energy source and carbon source to transform into other organic molecules
    • examples: animals and fungi and many bacteria
  8. Define photoheterotroph
    • Use light as energy source but obtain carbon from food
    • example: certain bacteria
  9. What is asexual reproduction?
    • "without sex"
    • no union of gametes
    • little to no genetic difference
  10. What is sexual reproduction?
    • union of gametes
    • genetic difference between parents and offspring
  11. What is the definition of evolution?
    genetic and resulting phenotpic change (observable property) in populations of organisms from one generation to the next
  12. What are some examples of "living fossils"?
    • brachiopod
    • ginkgo biloba
    • horseshoe crab
    • coelocanth
  13. How is genetic analyses revolutionizing our understanding of Neanderthals?
    • DNA analyses indicate that Neanderthals and Humans interbred
    • DNA extracted from leg bones, now 60% of Neanderthal genome has been sequenced
    • Found Neanderthal DNA fragments are scattered through genome of non-African ancestry
  14. What is the importance of the Miller and Urey experiments (1950s)?
    • Process:
    • 1. mimic earth's early atmosphere (CH4, N2, NH3, H2, H2O, CO2)
    • 2. zap with electricity
    • 3. condense and analyze for simple organic compounds
    • Found:
    • all 5 bases in DNA and RNA
    • 17/20 amino acids used in protein synthesis
    • 3- and 6-carbon sugars
  15. What is a "recipe for life"?
    • 1. take early (pre-O2) atmosphere and zap with lightning - form monomers (amino acids, nucleotides, sugars)
    • 2. place monomers in locations favorable to condensation reactions (clay shores, hydrothermal vents, hot pools) - polymers (proteins, carbs, RNA/DNA, lipids)
    • 3. RNA before DNA - simpler, acts as a catalyst
    • 4. lipids naturally form bilayer spheres - encapsulae RNA providing more stable environment
    • 5. self-replicating structure - nucleic acid inside and nucleotides on outside
  16. how long ago did earth form?
    ~4.5 bya
  17. how long ago did life originate?
    ~3.8 bya
  18. how long ago did photosynthesis arise?
    ~2.5 bya
  19. how long ago did eukaryotes arise?
    1.5 bya
  20. how long ago did multicellular life form?
    700 mya
  21. how long ago was the "Cambrian explosion"?
    542 mya
  22. When did life on land begin?
    420 mya
  23. When did the first humans arise?
    ~200,000 ya
  24. What are some examples of physical changes to earth that happened over time?
    • movement of continents - continental drift
    • volcanic activity, meteorite collisions
    • rise and fall of sea levels
    • changing temp
    • increase in O2
  25. What's an example of a physical change that life brought to Earth instead of the other way around?
    Produced an increase in O2
  26. how did photosynthesis arise?
    • early atmosphere had no oxygen
    • light energy splits water, organisms used free electrons to reduce carbon dioxide and build organic molecules
    • oxygen is a waste product
    • leads to aerobic respiration
    • leads to more complex life (eukaryotic, multicellular)
  27. Which species evolved photosynthesis first?
    Cyanobacteria - photosynthetic prokaryotes, formed stromatolites
  28. What is the precambrian era?
    • lasted from ~4.5bya to 542 mya
    • largely unicellular, prokaryotes
    • life confined to oceans
  29. What is the paleozoic era?
    • "old life"
    • lasted from 542mya to 251mya
  30. What is the mesozoic era?
    • "middle life"
    • lasted from 251mya to 65mya
  31. What is the cenozoic era?
    • "new life"
    • from 65mya-present
  32. in which geological era did stromatolites form?
    • (layered cyanobacterial concretions
    • in the precambrian era
  33. When did eukaryotes evolve?
    late precambrian (last 1/3 of era)
  34. What are "Ediacarian animals"?
    larger soft-bodied animals
  35. when did Ediacarian animals evolve?
    late precambrian era (last 1/3)
  36. How does the paleozoic era begin?
    begins with Cambrian explosion - relatively rapid diversification of multicellular life
  37. What is Burgess Shale?
    • In British Columbia
    • discovered in 1909
    • best fossil site of cambrian animals
    • excellent preservation of soft and hard parts
  38. Which group of animals is the most diverse and numerous?
  39. What is the ordivician age?
    • During paleozoic era
    • 488-444mya
    • radiation of marine organisms (like brachiopods and mollusks)
    • ended with massive extinction (75% of species eliminated) because of sea level and ocean temperature drop
  40. what is the silurian age?
    • during mid paleozoic era
    • 444-416mya
    • marine life rebounded
    • animals swim and feed above ocean bottom, jawless fishes diversified
    • colonization of land (simple plants, arthropods like millipedes and scorpions among firtst)
  41. what is the devonian age?
    • during mid-paleozoic
    • 416-359mya
    • "age of the fishes"
    • in oceans: fishes diversify - evolve jaws, loss of heavy armour, limbs & radiation of corals and shelled cephalopods
    • on land: common are large club mosses, ferns and horsetails & first seed plants (gymnosperms) & spiders and insects
    • ends with mass extinction (75% of marine life wiped out)
  42. what is the carboniferous age?
    • during late paleozoic
    • 359-297 mya
    • "age of amphibians or coral"
    • amphibians diversify and are abundant
    • land dominated by giant swamp forests (ferns and horsetails)
    • insects evolve flight
    • crinoids abundant in oceans
    • amniotic egg evolves
  43. What is the amniotic egg?
    • a shelled egg with extra-embryonic membranes
    • key adaptation that allowed organisms (like reptiles, birds, and mammals) to reproduce on land
    • modifications exist across amniotic animals
  44. what is the permian age?
    • during late paleozoic era
    • 297-251 mya
    • reptiles diversify and begin to dominate over amphibians - many new lineages evolve
    • largest mass extinction in earth's history (96% of life became extinct)
    • oxygen concentrations dropped by 50%
  45. what is the triassic age?
    • during mesozoic era
    • 251-200 mya
    • early dinosaurs
    • first mammals
    • diversification of invertebrates
    • ends with mass extinction (~65% of species go extinct)
  46. what is the jurassic age?
    • during mesozoic era
    • 200-145 mya
    • large terrestrial herbivores and predators are dinosaurs
    • flying reptiles appear (pterosaurs)
    • first fossils of flowering plants
    • radiation of ray-finned fishes
  47. what is the cretaceous age?
    • during mesozoic era
    • 145-65 mya
    • dinosaur continue to diversify
    • first snakes appear
    • mammals radiate, but most small
  48. Why was there a mass extinction during the cretaceous age?
    • Probable cause - meteorite impact
    • On land all animals >25kg became extinct, plus many insects
    • Probably died because of lack of food
  49. How do we know there was a mass extinction during the cretaceous age?
    • 1. High concentrations of iridium (rare on earth, but abundant  in meteorites)
    • 2. Crater loacated off Yucatan, 180km in diameter and based on this size, estimate meteorite collision released 100 megatonnes of high explosives
  50. What is the cenozoic era?
    • 65mya - present
    • "age of mammals"
    • starts with the recovery from mass extinction
    • radiation of birds
    • radiation of flowering plants (angiosperms - evolve symbioses with nitrogen fixing bacteria, insects)
    • radiation of mammals - hominids
  51. When did our species appear?
    About 200,000 years ago
Card Set
BIOL111 Lectures 1-2
BIOL111 Lectures 1-2