Artificial Selection Alters Species to Meet Human Needs
- Humans have used artificial selection for thousands of years to shape plants and animals to serve specific purposes.
- Unlike natural selection, which is driven by the environment, artificial selection is guided by human preferences.
- Modern corn, with its rows of plump kernels, originated from teosinte, a wild grass with tiny, hard seeds.
- Selective breeding over generations transformed teosinte into the corn we know today, increasing yield from 150 kg/ha to over 4,100 kg/ha.
Selective Breeding Amplifies Desired Traits Over Generations
- Artificial selection works by identifying and amplifying traits beneficial to humans:
- Desirable Traits Are Identified: Traits like high milk yield, disease resistance, or faster growth are chosen.
- Breeding Is Controlled: Only individuals with the selected traits are allowed to reproduce.
- Repetition Strengthens Traits: Over generations, the desired traits become more common.
- Dogs: Selective breeding transformed wolves into specialized breeds like greyhounds for speed and sheepdogs for herding instincts.
- Cattle: Breeds like Holstein are optimized for milk production, while Angus are bred for high-quality meat.
Artificial Selection Focuses on Human Goals, Not Nature’s Needs
While natural selection favors traits that enhance survival and reproduction, artificial selection favors traits that meet human needs, often at the expense of an organism's fitness.
