What is Artificial Selection?

• Artificial selection is when humans choose which organisms to breed, based on desired traits.
• This is also called selective breeding.
• It is a form of evolution driven by humans (not nature).

How It Works

• Variation exists naturally in a population (e.g., size, shape, color).
• Humans select individuals with desirable traits (e.g., faster, sweeter, more productive).
• These are bred to pass the trait to the next generation.
• Over many generations, the trait becomes common or fixed in the population.

Examples of Artificial Selection

Plants – Brassica oleracea (wild cabbage)

From one ancestral plant, humans bred different vegetables selecting for various characteristics:

• Cabbage – selected for large leaves
• Broccoli – selected for large flower heads
• Kale – selected for edible leaves
• Brussels sprouts – selected for large buds
• Cauliflower – selected for tight flower clusters

🔍 These all came from wild cabbage, showing how genetic variation + artificial selection can create many forms.

Animals – Dog Breeds

Dogs have been selectively bred for thousands of years:

• Greyhounds – bred for speed (hunting)
• Labradors – bred for friendliness (companions)
• Border Collies – bred for intelligence and herding
• Bulldogs – bred for strength and guarding

🔍 All dogs are descended from wolves, but artificial selection created hundreds of breeds with different appearances and behaviors.

Genetic Variation

• Genetic variation means differences in DNA among individuals in a population.
• It is the raw material for artificial selection.
• Sources of variation:
  • Mutations
  • Sexual reproduction
  • Gene shuffling during meiosis

Key Points

• Artificial selection needs variation to work.
• Traits must be heritable (passed on by genes).
• Unlike natural selection, humans decide which traits are “fittest.”

Written by Kasiban Parthipan