SELECTIVE BREEDING

• SELECTIVE BREEDING:

  • Humans breed PLANTS and ANIMALS for particular GENETIC characteristics
  • Done for THOUSANDS of YEARS- bred FOOD crops from wild PLANTS and DOMESTICATED animals
• 4 EXAMPLES:

  • DOMESTICATED dogs -> bred -> GENTLE nature
  • PLANTS -> bred -> large FLOWERS
  • COWS -> bred -> more MILK / MEAT
  • WHEAT -> bred -> resistant to DISEASE
• HOW IS IT CARRIED OUT?

  • Mixed POPULATION of MALE + FEMALE animals -> largest MALE and FEMALE bred TOGETHER (sexual reproduction)
  • This means that they produce genetically DIFFERENT offspring, where some are LARGE and are SMALL
  • The LARGEST male and female are then BRED together and the largest of their OFFSPRING are bred
  • This occurs over many GENERATIONS until all the OFFSPRING are LARGE
• PROBLEM:

  • Closely RELATED animals / plants -> INBREEDING
  • Means that plants can get DISEASES / INHERITED disorders

  DOGS:

  • JOINT problems
  • HEART disease
  • EPILEPSY