1.3

• What is the theory of evolution by natural selection?

  Survival of the fittest individuals
• Why do individuals of a species show variation?

  Due to genetic differences among individuals
• What happens to individuals with characteristics suited to the environment?

  They survive and breed successfully
• How are desirable characteristics passed on?

  They are inherited by offspring
• Why was Darwin's theory of evolution initially not accepted?

  People believed in creationism
• What was a major reason for the rejection of Darwin's theory?

  Insufficient evidence to support it
• What was unknown at the time of Darwin's theory?

  The mechanism of variation and inheritance
• What was Jean-Baptiste Lamarck's theory of inheritance?

  Changes during an organism's lifetime can be inherited
• What is speciation?

  Formation of a new species
• How does speciation occur?

  Populations cannot interbreed to produce fertile offspring
• What defines a species?

  Organisms that can interbreed to produce fertile offspring
• What is the process of speciation through geographic isolation?

  • Two populations are separated geographically
  • Geographic isolation prevents interbreeding
  • Different selection pressures lead to mutations
  • Over time, populations evolve to be unable to interbreed
• Why is genetic variation important in speciation?

  It produces phenotypic variation suited to the environment
• How did Mendel study inheritance?

  Through breeding experiments on plants
• Why was Mendel's work not recognized until after his death?

  He could not explain the mechanism of inheritance
• What hindered the communication of Mendel's work?

  It was not published in a reputable journal
• Name two kinds of evidence used to show evolution.

  Fossils and antibiotic resistance
• How are fossils formed?

  • Organism parts not decayed due to absent decay conditions
  • Parts replaced by minerals during decay
  • Traces preserved in sediment and become rock
• Why are there few traces of early life-forms?

  Most early life-forms were soft-bodied
• How do fossils provide evidence for evolution?

  They show how organisms change over time
• What do branches in evolutionary trees indicate?

  Where speciation has occurred
• What is extinction?

  No individuals of a species are alive
• What factors may lead to extinctions?

  New disease, predation, competition
• What enables bacteria to evolve quickly?

  The fast rate of their reproduction
• Outline the process of antibiotic resistance in bacteria.

  • Mutations create genetic variation
  • Some strains resist antibiotics
  • Resistant strains survive and reproduce
  • Population of resistant strains increases
• Why are resistant strains of bacteria dangerous?

  People have no immunity and no effective treatment
• Name an example of a resistant strain of bacteria.

  MRSA
• What can be done to reduce antibiotic resistance?

  • Avoid inappropriate antibiotic prescriptions
  • Complete prescribed antibiotic courses
  • Restrict agricultural antibiotic use
• Why is it difficult to keep up with emerging resistant strains?

  Developing antibiotics is costly and time-consuming