The enzyme lactase allows our bodies to tolerate the lactose found in milk. Evolution has kept this enzyme active even after we stop drinking our mother’s milk (Flatow). This genetic adjustment occurred around the same time cows and goats were domesticated, about five to ten thousand years ago ("Are Humans Still Evolving?"). Our bodies have changed in other ways as well. It has been proven that our brains have been decreasing in size. The average volume has reduced by around ten percent over the last thirty thousand years. Several theories exist for why this is happening. Several believe it means our brains have started to rely too much on technology, causing us to be weaker minded. Others however believe it could also be that our brains have become increasingly efficient and do not need to as much space to accomplish all of its regular functions (Hullinger).
Our bodies have also started increasing the production of bone tissue. A mutation has been found that increases the production of lipoprotein receptor-related protein 5 (LRP5), a gene used in coding protein. Generally, mutations in this gene cause osteoporosis. A mutation has been made that increases production of this protein, causing stronger bones to occur …show more content…
The majority of the ten thousand genes that have appeared in the last forty thousand years appear devoted to strengthening our immune system. One gene, caspase ten, works directly with our immune system against bacteria. A version of the co-receptor of the HIV virus (CCR5) protects people almost completely from the particle. This genetic variant can be found in thirteen percent of the population of Western Europe. There remain other genetic variants created from living in cities that make us more resistant to ailments similar to tuberculosis and leprosy ("Are Humans Still Evolving?") (Tyson)