Big Idea I

Evolution is ongoing. One way evolution can be understood is by studying crop domestication.

Domestication is the process by which plants and animals are genetically modified over time for traits that are more desirable for humans (e.g. higher yield, larger fruit, better flavor). This process mirrors evolution – natural selection – except that humans are doing the selection.

Maize is an excellent example of domestication – evolution in action – as we can compare current varieties of maize with its wild ancestor, teosinte. Maize was domesticated approximately 6,000 years ago. Humans selected those plants with desirable characteristics such as more kernels, larger kernels, and more edible kernels (that had lost the hard outer glume). Scientific studies have identified the genes that were responsible for these changes and how the DNA sequence has changed over time. Humans continue to modify maize by creating varieties that have improved nutrition, disease and insect resistance, and drought tolerance.