Genetically modified foods, or GMOs, inspire strong reactions nowadays, but humans have been tweaking the genetics of our favorite produce for millennia. Whether it involved splicing genes from other organisms to give plants desired traits or using selective breeding over a long period of time, according to Business Insider, crops today are vastly different from those in the past. Take for example North American sweetcorn. Natural corn was first domesticated in 7,000 BC and was dry like a raw potato. Today, corn is 1,000 times larger than it was 9,000 years ago and much easier to peel and grow.