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Are Humans Still Evolving?
Are Humans Still Evolving?
By: Clker-Free-Vector-Images on Pixabay.com
It’s easy to assume that due to our recent technological advances that humans have grown past the need to evolve. Well, that is false! Evolutions are still happening in our lives and around us. Many people tend to think of evolution as the same as natural selection or selection pressure. However, evolution can occur without these factors. For example, in the stone age, our ancestors used natural selection and selection pressure in cases like hunting. The ones who can outrun a mammoth or another animal were the ones who survived and were able to go on and have children. Since that natural selection, humans evolved over time to be fast runners (Hamrud, n.d).
Evolution does not need natural selection or selection pressure to happen. This can happen by a change in gene variants over time or even a change in our DNA that we don’t even realize (Hamrud, n.d). However, selection pressure and natural selection can still happen. Usually, mammals lose the ability to digest milk after they are done breastfeeding. Many humans have developed lactase persistence, which means we can make lactose throughout our lives (Hamrud, n.d). Thanks to the gene variant, -13910*T, humans were able to attain lactase persistence. This change was brought about by ourselves when humans first started domesticating animals for milking purposes.
Although it is unclear how humans will evolve next, many people consider that one - day technology will come into play. That one day we will put our phones in our heads and access our brain through our computer. Or that humans might be able to alter DNA to an extreme. Despite the interest, this may spark, using these modes of evolution might be harmful to us in the future. Technology can completely change human life if it begins to become a part of ourselves.
By: Pete Linforth on Pixalby.com
Examples of Evolution Today
Evolution can be complex at times. It’s hard to keep up with the changes that humans have had to adapt to throughout their time on Earth. However, there are some evolutions that don’t have a true purpose and some that humans brought upon themselves. For example, there are some humans that have evolved to survive and live in higher altitudes. Tibetans who live in the Himalayan mountains have evolved to survive in high altitudes with low oxygen levels. Research shows that their blood is “genetically predisposed to produce more oxygen-transporting hemoglobin protein” (Kane, 2016). This evolution is dated back to only 3,000 years ago. Another example is the erasure of wisdom teeth. Back when humans had to hunt and search for food, wisdom teeth were used for tougher and strenuous foods. With the growth of our brains and our jaws becoming smaller, our wisdom teeth have no room to grow and stay under the gums. A mutation one thousand years ago caused wisdom teeth not to grow at all and now 1 out of 4 people have at least one missing wisdom tooth (Kane, 2016).
Portions of the human body continue to evolve everyday. The sex of a baby is determined by the pairing of chromosomes the child receives from the parents. Two X chromosomes result in a female offspring, while an X and a Y chromosome produce a male offspring. The Y chromosome has been shrinking, evolving, over the course of human existence and continues evolving everyday. These X and Y chromosomes each carry vital genetic information. Genes can mutate over time and these mutations can prompt dangerous outcomes. However, the chances of mutation is decreased when the chromosomes recombine with one another (Whitcomb, 2020). The X chromosomes can swap arms to avoid these mutations since there are two X chromosomes to mix and match with. The Y chromosome, however, cannot do so since the Y chromosome is not similar enough to an X chromosome to swap and finding two Y chromosomes in one person is extremely unlikely. This results in the Y chromosome shrinking to avoid this risk of mutation. It is suspected that the Y chromosome and the X chromosome once carried an equal amount of genes, around 1,669 genes 166 million years ago (Whitcomb, 2020). Given that the Y chromosome now carries about 45 genes to the upwards of 1200 genes on the X chromosome, the Y chromosome has shrunk dramatically to reduce this mutation risk (Schwartz, 2013). The human body continues to evolve everyday.
References
Hamrud, Eva “Are Humans Still Evolving? Scientists Weigh In.” ScienceAlert, www.sciencealert.com/are-humans-still- evolving#:~:text=Evolution%20can't%20be%20stopped,natural%20selection%20is%20always%20happening.&text=Huma ns%20are%20still%20evolving%2C%20and,to%20change%20in%20the%20future.
Kane, Sean. “7 Strange and Surprising Ways That Humans Have Recently Evolved.” Business Insider, Business Insider, 3 Aug. 2016, www.businessinsider.com/recent-human-evolution-traits-2016-8#6-alcohol-flush-reaction-6.
Schwartz, C. E. (2013). X Chromosome. In S. Maloy, & K. Hughes (Eds.), Brenner's Encyclopedia of Genetics (Second Edition) (pp. 352-354). Academic Press. https://doi.org/10.1016/B978-0-12-374984-0.01650-8
Ward, Peter. “What May Become of Homo Sapiens.” Scientific American, Scientific American, 1 Nov. 2012, www.scientificamerican.com/article/what-may-become-of-homo-sapiens/.
Whitcomb, I. (2020). Is The Y Chromosome Dying Out? Live Science. https://www.livescience.com/y-chromosome-dying.html
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