Final answer:
Farmers and horticulturalists bred broccoli, cauliflower, kale, and cabbage from the wild mustard plant through artificial selection. Artificial selection is the process in which humans select and breed plants or animals to pass on specific traits to the next generation. It provides evidence for evolution by natural selection.
Step-by-step explanation:
Farmers and horticulturalists bred broccoli, cauliflower, kale, and cabbage from the wild mustard plant through artificial selection. Artificial selection occurs when humans select and breed plants or animals to pass on specific traits to the next generation. In this case, farmers selectively bred plants with desirable traits, such as larger or more nutritious leaves, resulting in the development of these vegetables. Artificial selection is similar to Darwin's conception of natural selection in that both involve the differential reproduction of individuals with favored traits, but artificial selection is carried out by humans instead of being driven by natural factors.
Artificial selection does provide evidence for evolution by natural selection. The process of artificial selection demonstrates that desirable traits can be intensified or created through selective breeding. These bred plants can then be seen as examples of the potential changes that can occur over time through natural selection, where individuals with advantageous traits have a better chance of surviving and reproducing in their natural environment.