Selective Breeding

• Crops and animals improved through selective breeding


  • Crops with disease resistance
  • Animals that produce more meat or milk
• Selective Breeding


  Humans artificially select the plants or animals that are going to breed so that the genes for particular characteristics remain in the population
• Selective breeding is when humans artificially select the plants or animals that are going to breed so that the genes for particular characteristics remain in the population
• Organisms selectively bred to develop features

  • Dogs with a good, gentle temperament
  • Decorative plants with big or unusual flowers
• Selective Breeding process


  1. Select the ones which have the characteristics you're after

  2. Breed them with each other

  3. Select the best of the offspring, and breed them together

  4. Continue this process over several generations, and the desirable trait gets stronger and stronger
• Selective breeding


  Also known as 'artificial selection'
• Selective breeding in agriculture

  • Breed together the cows and bulls with the best characteristics for producing meat to improve meat yields
• Selective breeding is nothing new-people have been doing it for thousands of years
• Selective Breeding


  • It reduces the gene pool-the number of different alleles (forms of a gene) in a population
  • Inbreeding can cause health problems because there's more chance of the organisms inheriting harmful genetic defects when the gene pool is limited
  • There can also be serious problems if a new disease appears, because there's not much variation in the population
• Inbreeding


  The farmer keeps breeding from the "best" animals or plants which are all closely related
• Some dog breeds are particularly susceptible to certain defects because of inbreeding-e.g. pugs often have breathing problems