Selective breeding is a form of artificial selection, whereby man intervenes in the breeding of species to produce desired traits in offspring. By breeding members of a species with a desired trait, the trait’s frequency becomes more common in successive generations. Selective breeding provides evidence of evolution as targeted breeds can show significant variation in a (relatively) short period
Example 1: Horse Breeding
Horses have been selectively bred across many generations to produce variation according to a targeted function
Example 1: Horse Breeding
Horses have been selectively bred across many generations to produce variation according to a targeted function
- Race horses have been bred for speed and hence are typically leaner, lighter, taller and quicker
- Draft horses have been bred for power and endurance and hence are sturdier and stockier
Example 2: Cow Breeding
Cows have been selectively bred across many generations to produce offspring with improved milk production
Farmers have also targeted the breeding a cows with a mutation resulting in increased muscle mass
Cows have been selectively bred across many generations to produce offspring with improved milk production
Farmers have also targeted the breeding a cows with a mutation resulting in increased muscle mass
- The resulting stock of cattle (termed Belgian Blue) have excessive bulk and produce more edible lean meat
Example 3: Dog Breeding
Dog breeds show an enormous amount of variety due to the targeted selection of particular traits by man
Dog breeds show an enormous amount of variety due to the targeted selection of particular traits by man
- Hunting dogs (e.g. beagles) were typically bred to be smaller in stature so as to enter fox holes
- Herding dogs (e.g. sheep dogs) were bred for heightened intelligence in order to follow herding commands
- Racing dogs (e.g. greyhounds) were specifically bred to be sleek and fast
- Toy dogs (e.g. chihuahuas) were selectively bred for their dimunitive size
Variation in Domesticated Dog Breeds