Artificial Selection

• What is artificial selection?

  Humans choose organisms with desirable traits
• What is another term for artificial selection?

  Selective breeding
• How long have humans been selectively breeding organisms?

  For thousands of years
• What do breeders select based on in artificial selection?

  Phenotypes, not genotypes
• What can happen if breeders do not understand genetics?

  They may enhance unwanted traits
• What negative effects can arise from enhancing linked traits?

  It can harm the organism's health
• What are the steps in the process of artificial selection via selective breeding?

  1. Population shows phenotypic variation
  2. Breeder selects individuals with desired phenotypes
  3. Selected individuals are not closely related
  4. Selected individuals are bred together
  5. Offspring are tested for desirable traits
  6. Best offspring are chosen for further breeding
• What characteristics are animals selectively bred for?

  Higher yield of milk or meat
• What is the economic benefit of selective breeding in cattle?

  Increased milk yields
• What health issues can arise from selective breeding in cows?

  Mastitis, milk fever, and lameness
• What are the three phenotypes horses can have for racing?

  Sprinting, endurance, all-rounder
• What is a goal of selective breeding in racing horses?

  To produce fast-sprinting offspring
• What characteristics are plants selectively bred for?

  • Disease resistance
  • Increased crop yield
  • Hardiness to weather
  • Better tasting fruits
  • Large or unusual flowers
• What is the purpose of introducing a fungus-resistant allele in wheat?

  To increase crop yield
• What diseases affect rice plants?

  Bacterial blight and rice blast
• Why is maintaining genetic material important in artificial selection?

  To prevent a small gene pool
• What is inbreeding depression?

  Reduced vigor from breeding closely related individuals
• How can farmers prevent inbreeding depression?

  By outbreeding with wild type varieties
• What is hybrid vigor?

  Increased growth and survivability
• What ethical concerns arise from selective breeding?

  Increased chance of harmful genetic defects
• What health issues are common in Bulldogs and Pekinese?

  Breathing problems due to short snouts
• What condition do large dogs like St. Bernards suffer from?

  Hip dysplasia
• What health issue do Golden Retrievers commonly face?

  Malignant blood vessel tumors