Final answer:
Examples of unintentional selection include ancient farmers selecting wheat and barley for thinner husks and more seeds, leading to domesticated varieties, and the transformation of teosinte into modern maize.
Step-by-step explanation:
One example of unintentional selection of plant attributes for domestication in ancient agricultural practices can be seen in the domestication of wheat and barley. The ancient wild varieties of these crops had heavy husks which protected the seeds for survival through the winter. Farmers, more interested in the seeds than the husks, unintentionally selected for plants with thinner husks and more seeds, leading over time to the domesticated forms that are much more seed-heavy and have thinner husks than their wild ancestors. This process of unintentional selection is a fundamental part of the genesis of agriculture, where humans chose plants with favorable traits to cultivate, unknowingly influencing their genetic makeup and leading to plants that were more suited to human use.
Another notable example includes the transformation of teosinte, a wild plant with small seeds, into modern maize (corn). This was achieved through selecting for desirable traits over generations, which unknowingly altered its genetic makeup to produce a plant with substantially larger kernels suitable for human consumption. Such changes reflect the immense impact of unintentional human selection on the characteristics of plant species under domestication.