Our evolutionary journey began in the deep oceans of Earth. Some fish thought - "Hey, maybe I should check out what it's like to breathe outside of water". At some point, one of these fish species succeeded and life on land began as we know it now. Scientists believe a "comb jelly" is the earliest species on Earth.
The fish species that facilitated life on land evolved from their immediate ancestors 360 million years ago, most probably from species like hagfish and lampreys. Most of our characteristics like shoulders, elbows, legs, a neck resemble what ancient fish that were able to survive on land would possess. Sure, our immediate ancestors are still apes - because of the striking similarity we possess.
Evolution is a fact and the constantly changing nature of our surroundings and bodies will continue to evolve in the future. For now, let's focus on six recent evolutionary changes that have been reported among human beings:
1. A new artery growing in arm
Just last week, it was reported by the Journal of Anatomy that many human beings have developed a new artery - highlighting the evolutionary processes at play inside modern humans. Situated in the centre of one's forearms, the artery in question usually disappears in the womb.
Now that it is being retained among many people, we have additional vascular tissue.
2. Lactose intolerance and tolerance
People in India still grimace at the idea of someone having allergies. But allergies of all types are extremely common - to nuts, to lactose, and even to wheat. Most people do not realise their allergies and continue to live on with them. Milk contains lactose which many people simply cannot digest. This causes bloating, cramps and vomiting among those people.
Yet, our ability to tolerate milk didn't happen naturally. It was caused by genetic changes between 5,000 and 10,000 years ago among European societies that first embraced milk. Essentially, we evolved with our dietary needs but not everyone could adjust. In Africa, this tolerance was developed as recently as 3,000 years ago.
3. Immune system's protective gene
The ability to fight viruses and diseases is basically generational advantage. The fact that the common cold doesn't kill people anymore is testimony to how scores of humans have died due to viral infections and diseases.
Those lucky enough to survive passed on these evolutionary traits to their offspring... and so on.
Think of Covid-19 - in a few years from now it wouldn't be as lethal as it now and should receive the same treatment as the seasonal flu or a bad cold.
Caspase-12 gene is part of body's natural anti-bacterial defences. But it simply remains inactivated among human beings now, for it caused poor response to bacterial infections. Human bodies simply evolved to suppress this particular gene among many things.
4. Body temperature
Did you think that humans have the current average body temperature since we started ruining, err, living on this planet? The answer is no.
Since 1868, 98.6 degree Fahrenheit is considered the normal average temperature of a healthy body.
More than that is a fever, and anything below hypothermia.
Julie Parsonnet a professor of medicine at Stanford University conducted a study that found that average temperature among humans is dropping by 0.5 degrees every decade - we are literally cooling down!
The real average temperature of humans now is 97.9 degree Fahrenheit - bet you didn't know this! Also looks like humans are evolving to get cooler?