3. genetic diversity

• "the increase of Bt crop plants caused mutation in one of the insect species and this mutation spread to other species of insect. was he correct?"

  NO!!

  • mutations are spontaneous and random
  • only the rate of mutation is affected by the environment
  • different species do not produce fertile offspring
  • so gene cannot be passed from one species to another

  
• "why was there a time lag between the introduction of Bt crops and appearance of first insect that was resistant to Bt toxin?"

  • initially only a few insects with favourable characteristics
  • insects with allele are more likely to reproduce passing on allele
  • takes many generations for allele to become most common allele of this gene