Humans have evolved in the way we digest lactose. “This is because they carry a regulatory change in the region of DNA that controls the expression of the gene that codes for lactase. This DNA change enables the lactase gene to be switched on and lactase production to continue, even after weaning.” “Milk may have also prevented death from starvation when crops failed and food was scarce. Those who could not tolerate lactose would die of starvation, while those who could tolerate lactose would survive.” (http://www.yourgenome.org) So now people are able to drink milk or eat things with milk in them cause the DNA has changed.People could have died if they couldn’t tolerate …show more content…
“Since the disease often targets humans in earlier life, there was such a strong pressure to evolve defenses from malaria - any genetic factor that confer resistance against it would give descendents a chance to have offspring, while those without protection were more likely to not reproduce.” (http://www.livescience.com) If we didn’t evolve to where we were less likely to get malaria it would be harder for us to reproduce. Then there wouldn’t be anymore offspring. “There are lots of examples of defenses against malaria. Sickle cell anemia is the best known - the disorder deforms red blood cells into sickle shapes, which can impair blood flow, thus damaging tissues, this malformation also prevents the malaria parasite from infesting blood cells.” (http://www.livescience.com) There are prevention against malaria and the can show how we have