How did selective breeding change crops and domesticated animals?

Selective breeding, also known as artificial selection, is the process of mating individuals with specific, desirable traits to increase the frequency of those traits in a population. By isolating and propagating specific genotypes, humans have profoundly altered the biology of plants and animals over thousands of years to suit economic or aesthetic needs.12

Impact on Crops

Selective breeding has transformed wild plants into productive cultigens that are often entirely dependent on human care. For example:3
* Corn: Humans selectively bred teosinte for increased kernel numbers, eventually creating modern corn.13
* Cruciferous Vegetables: Selection from a common wild mustard ancestor led to diverse varieties like kale (large leaves) and cauliflower (enlarged flower buds).1

Impact on Animals

Domestication has caused significant shifts in seasonal biology, such as the ability to reproduce year-round and reduced molting rhythms. Selective breeding has also created immense morphological diversity; for instance, dogs have been bred from wolves into over 400 distinct breeds. However, intense selection can reduce genetic diversity, sometimes leading to health issues, such as the breathing difficulties seen in French Bulldogs.21