• Question: Have we evolved anymore (through immunity, characteristics, etc) since we became homosapiens?

    Asked by rowanxmas18 to James, Anthony, Alice on 7 Jan 2019. This question was also asked by yasminxmas18.
    • Photo: Edward Morrison

      Edward Morrison answered on 7 Jan 2019:

      It depends on when you think “Homo sapiens” began. Humans split from the human-chimp ancestor some 5-7 million years ago and we have changed hugely since then.

      Paleontologists find fossils from about 1000000 years ago that look the same as modern humans and so they call these Homo sapiens. We have definitely changed since then in other ways though as we see diversity in human skin colour, hair type etc. that all happened after we were anatomically modern.

      So any genetic racial differences we see, including susceptibility to particular diseases, is due to evolution since being Homo sapiens.

    • Photo: Gemma Chandratillake

      Gemma Chandratillake answered on 8 Jan 2019:

      We can see evidence of human evolution in the different frequencies of different characteristics in different populations e.g. lactose tolerance/intolerance. Humans would have originally turned off the gene to digest milk after being weaned from mother’s milk (no point in making an enzyme, lactase, that you’re not using). But, after some human groups began herding animals, there was a selective advantage in being able to digest milk (more nutrition) so evolution led to the lactase gene being kept on into adulthood in those populations. We see different frequencies of the genetic variants that cause sickle-call anemia and thalassemia in regions where malaria is found as compared to regions where it is not present. This is because, in regions with no malaria, these changes are harmful and therefore are selected against in the population, but in malarial regions, carrying variants in these genes can protect against malaria so there is selection acting to maintain these variants in the population in these regions.