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Flashcards · Biology

Evidence for Evolution and Classification

92 cards from 6 lessons

  1. What is a fossil?

    The remains of an organism from millions of years ago, found in rocks.

  2. Name the three ways in which fossils form.

    Parts not decayed, parts replaced by minerals, and preserved traces.

  3. Why might an organism not decay?

    One or more of the conditions needed for decay is absent.

  4. Give an example of a place where decay is prevented.

    Amber, ice or a peat bog.

  5. What replaces the parts of an organism in some fossils?

    Minerals.

  6. Give three examples of trace fossils.

    Footprints, burrows and rootlet traces.

  7. Why have early soft-bodied organisms left few fossils?

    They have no hard parts, so they decayed without leaving traces.

  8. What destroyed many early fossils?

    Geological activity.

  9. Why can scientists not be sure how life began?

    The traces of the earliest soft-bodied organisms were mostly destroyed.

  10. What can fossils show about how organisms have changed?

    How much or how little they have changed.

  11. In undisturbed rock layers, which fossils are older?

    Those in the deeper layers.

  12. What kind of fossil is Archaeopteryx?

    A fossil with features of both birds and reptiles.

  13. Is the fossil record complete?

    No. Most organisms never form fossils.

  14. What type of rock usually contains fossils?

    Sedimentary rock.

  15. What other evidence supports Darwin's theory, besides fossils?

    Genes passing on characteristics, and antibiotic resistance in bacteria.

  16. A fossil in amber, a bone with minerals and a footprint and burrow, with no labels. Name the three ways in which fossils form and give an example of each. (Look at the blank diagram.)

    1 Parts that have not decayed, such as an insect in amber. 2 Parts replaced by minerals, such as a bone. 3 Preserved traces, such as footprints and burrows.

  17. When does a species become extinct?

    When there are no remaining individuals of the species still alive.

  18. Name three factors that may contribute to extinction.

    New predators, new diseases and new competitors.

  19. How can environmental change cause extinction?

    The species cannot adapt, move or evolve fast enough.

  20. Give two catastrophic events that can cause extinction.

    A massive volcanic eruption and an asteroid collision.

  21. When did the dinosaurs go extinct?

    About 66 million years ago.

  22. What happened to the climate after the asteroid impact?

    It became colder as dust blocked the sunlight.

  23. Name an animal that humans hunted to extinction.

    The dodo.

  24. How does habitat destruction cause extinction?

    The species loses the place and the resources it needs.

  25. Why are small populations at greater risk?

    One event could kill all the individuals, and there is little variation.

  26. Why does low variation increase the risk?

    No individual may have the allele that helps it survive a change.

  27. What is a mass extinction?

    An event in which a large proportion of species die out together.

  28. Why are island species often at risk?

    They have not evolved defences against newly arrived predators.

  29. How do fossils show that extinction has happened?

    Fossils of species that no longer exist are found in rocks.

  30. Name one human activity that causes global warming.

    Burning fossil fuels.

  31. Is extinction always caused by humans?

    No. It has happened naturally throughout the history of life.

  32. Why can bacteria evolve rapidly?

    They reproduce at a fast rate.

  33. What produces new strains of bacteria?

    Mutations.

  34. What does antibiotic resistance mean?

    The bacteria are not killed by the antibiotic.

  35. What happens to non-resistant bacteria when an antibiotic is used?

    They are killed.

  36. What happens to resistant bacteria when an antibiotic is used?

    They survive and reproduce.

  37. Why does the population of the resistant strain rise?

    The survivors reproduce and there is no competition from the killed bacteria.

  38. Why does a resistant strain spread?

    People are not immune to it and there is no effective treatment.

  39. What does MRSA stand for?

    Methicillin-resistant Staphylococcus aureus.

  40. Do antibiotics work against viruses?

    No.

  41. Why should patients finish a course of antibiotics?

    So all the bacteria are killed and none survive to form resistant strains.

  42. Why should farm use of antibiotics be restricted?

    It gives bacteria more chances to evolve resistance.

  43. Why is developing new antibiotics difficult?

    It is costly and slow.

  44. Is antibiotic resistance evidence for evolution?

    Yes. It shows natural selection happening in bacteria.

  45. Can a single bacterium change to become resistant because it was exposed to an antibiotic?

    No. Resistance comes from random mutations, and the antibiotic selects the resistant ones.

  46. Why is a hospital a risky place for resistant bacteria to spread?

    Patients are ill, have wounds, and antibiotics are used a lot.

  47. Four panels of bacteria, showing one resistant bacterium surviving and reproducing, with no labels. Describe what is happening in each panel to explain how the population becomes resistant. (Bacteria and an antibiotic.)

    1 A mutation makes one bacterium resistant. 2 The antibiotic kills the bacteria that are not resistant. 3 The resistant bacterium survives and reproduces. 4 The population is now resistant and the strain can spread.

  48. Who developed the traditional system of classification?

    Carl Linnaeus.

  49. What is classification based on in the Linnaean system?

    The structure and characteristics of organisms.

  50. Name the seven ranks in order, from largest to smallest.

    Kingdom, phylum, class, order, family, genus and species.

  51. Which is the biggest group, kingdom or species?

    Kingdom.

  52. What is the smallest group in the Linnaean system?

    Species.

  53. What is the binomial system?

    Naming an organism using its genus and species.

  54. What does binomial mean?

    Two names.

  55. How is a binomial name written?

    Genus with a capital letter, then species with a lower case letter, in italics or underlined.

  56. What is the scientific name of humans?

    Homo sapiens.

  57. What is the genus of the lion and the tiger?

    Panthera.

  58. Why do scientists use scientific names instead of common names?

    They are the same in every country and name only one species.

  59. If two organisms are in the same genus, how closely related are they?

    Very closely related.

  60. What do organisms in the same family have in common?

    More characteristics than organisms in the same order.

  61. Which rank comes after class?

    Order.

  62. Give a memory aid for the ranks.

    King Philip Came Over For Good Soup.

  63. What new techniques led to new models of classification?

    Better microscopes and chemical analysis, and a better understanding of biochemical processes.

  64. Who developed the three-domain system?

    Carl Woese.

  65. What kind of evidence led to the three-domain system?

    Evidence from chemical analysis.

  66. Name the three domains.

    Archaea, Bacteria and Eukaryota.

  67. What are Archaea?

    Primitive bacteria usually living in extreme environments.

  68. What are Bacteria in the three-domain system?

    The true bacteria.

  69. Which organisms are in the domain Eukaryota?

    Protists, fungi, plants and animals.

  70. What do all eukaryotic cells have?

    A nucleus.

  71. What is an evolutionary tree?

    A diagram showing how scientists believe organisms are related.

  72. What data do scientists use to draw evolutionary trees?

    Classification data for living organisms and fossil data for extinct organisms.

  73. What does a branch point show on an evolutionary tree?

    A common ancestor from which two groups separated.

  74. On a tree, how can you tell which two organisms are most closely related?

    Their branches meet at the most recent branch point.

  75. Is classification a fixed fact?

    No. It is a model that changes with new evidence.

  76. Why were archaea given their own domain?

    Their chemistry is very different from that of true bacteria.

  77. Does the order of the tips on a tree show closeness?

    No. Only the branch points do.

  78. Who proposed the theory of evolution by natural selection?

    Charles Darwin.

  79. What was the name of Darwin's ship?

    HMS Beagle.

  80. Which years did Darwin's voyage take place?

    1831 to 1836.

  81. When did Darwin publish On the Origin of Species?

    1859.

  82. What are the three ideas of natural selection?

    Variation, survival of the best suited, and passing on the characteristics.

  83. Why did Darwin delay publishing?

    He spent years gathering evidence, until Wallace's letter prompted him.

  84. Give one reason why the theory was only gradually accepted.

    It challenged the idea that God made all the animals and plants.

  85. Give another reason why it was only gradually accepted.

    There was insufficient evidence at the time.

  86. What was not known until 50 years after publication?

    The mechanism of inheritance and variation.

  87. What did Lamarck suggest?

    Changes that occur in an organism during its lifetime can be inherited.

  88. Is Lamarck's idea correct?

    In the vast majority of cases, this type of inheritance cannot occur.

  89. How would Lamarck explain the long neck of a giraffe?

    The giraffe stretched its neck and passed on the longer neck.

  90. How would Darwin explain the giraffe's neck?

    Variation: those with longer necks survived and passed on their alleles.

  91. What did Darwin see on the Galapagos Islands?

    Finches with beaks of different shapes suited to their food.

  92. Was Darwin's theory developed by one person only?

    No. It developed from information gathered by many scientists.