Evolution Part.1 : Humans

Let’s talk about Evolution. We’ve all had that dispute with a Creationist that uses any desperate measure to attempt to prove intelligent design over Evolution.

There are modern day examples of how Evolution works and I will explore several of them.

Part 1: Human Evolution

Vestigial traits are examples of leftover muscles that Evolution has kept in some humans. Everyone knows someone who can move their ears, but can you? These muscles are auricle and are found in Dogs, Cats that are used to direct their ears towards sounds.

Hypoxia (mountain sickness) can range from headaches, to nausea and impaired thinking that is due to lack of oxygen in the atmosphere at high altitudes.

Andean inhabitants would have suffered greatly when they initially chose to live at high altitudes, but the human body can adapt, and to combat hypoxia the human body starts to carry more oxygen in red blood cells, thus making the people able to withstand the high altitudes.

Tibetans, however, do it differently than Andeans in that they do it respiratory by taking more breaths to compensate for lack of oxygen. Studies have also found that they have developed larger blood vessels that allow them to carry more oxygen, and they they have higher levels of hemoglobin.

Genetic mutations have also been studied in the Inuits of Greenland, and their bodies have adapted (due to their poor diets) to enable the body to control how it uses fat, and that provides the clearest evidence to date that human populations have adapted to particular diets.

The Inuit diet is an example of how high levels of omega3 fatty acids can counterbalance the bad health effects of a highfat diet.

Dr Pascale Gerbault (UCL Genetics, Evolution & Environment and UCL Anthropology), who co-authored a study, said:

“These findings give us important clues about how our diet and the way we metabolise our food has affected and probably still affects our evolution.”

Inuits have also been said to have more brown fat than inhabitants of warmer climates which burns energy to create heat.

Most animals have the the Jacobson‘s organ that is part of the vomeronasal system. Humans also have it, but it’s now redundant. Animals use it to seek pheromones, or marks that another animal has left so they can determine the sex. Scientists have found that in humans it potentially stopped working a long time ago, as there are no nerve endings found connecting to the brain.

Ever seen a Chimp use its back feet like hands so they can grip branches? This is because of the Plantaris Muscle. Humans also have this muscle but it’s superficial as we have no real use for it anymore, and a percentage of humans are now even born without it.

Wisdom teeth were needed when our ancestors needed to eat plants in a hurry to get enough food to get the nutrients needed when foraging. As human diets changed the third molar became redundant, and some people will live their entire life without them developing.

Another vestigial feature of humans is the third eyelid (Nictitating membrane)(plica semilunaris). In Gorillas this is still active, but in one of our closest relatives, the chimpanzee, it also appears to be dormant.

Most animals that use the third eyelid have it for protection, and to keep the eye clean. Why humans have evolved it away is unknown, but it may be because of change of habitat, and no natural predators.

The appendix which has been long known to be a useless evolutionary artifact can be removed with no harm to a person. The reasoning as to why we have it is unknown, but some scientists believe it to have once been part of the cecum which extinct ancestors used to help digestion.

My final example of human vestigiality is the coccyx, which is the remnants of a mammalian tail, which can consist of 3 to 5 bones. Whilst it serves no purpose as a tail anymore it does help hold certain essential muscles and ligaments in place.

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