Fruits and vegetables have changed a lot since the onset of agriculture 10,000 years ago, as generation after generation of farmers artificially bred crops to select for more desirable traits like size and taste.
But that change can be hard to visualize. So James Kennedy, a chemistry teacher in Australia, created some terrific infographics to show just how drastic the evolution has been. This one, for instance, shows how corn has changed in the last 9,000 years — from a wild grass in the early Americas known as teosinte to the plump ears of corn we know today:
The evolution of corn
The evolution of corn (maize) is a fascinating story. For a long time, scientists couldn’t figure out where domesticated corn originally came from — it doesn’t look like anything that grows in the wild. It took serious sleuthingby geneticists, botanists, and archaeologists to figure out that maize split off from teosinte grass some 9,000 years ago. (The two are surprisingly similar at the DNA level, differing by just a handful of genes.)
As maize became domesticated in Mesoamerica, it was radically alteredthrough selective breeding. Early farmers would examine their plants and save the seeds of those that were larger, or tastier, or whose kernels were easier to grind. By 4,000 BC, cobs were already an inch long. And within just a few thousands years, cobs had grown to many times that size.
Nowadays, corn is grown all over the planet and selective breeding is still ongoing — though in recent decades it’s also been combined with genetic engineering. Scientists have inserted genes from Bt soil bacteria into corn in order to ward off pests. And some researchers are now hoping to develop corn varieties that can withstand drought. And so on.