Hominals the ever changing species

Posted: April 25, 2014 in Education, History, Science
Tags: , , , , , , , , , ,

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Have you ever wondered if humankind as a whole is still evolving? It dawned on me that mutations happens more times than we think and what if we as a species still has some changing to do. If dinosaurs roamed the earth for over 100 million years and have undergone changes and we have only been on this planet for just under 200,000 years than it’s only logical to think our kind has a lot of evolving to go through.

The idea of evolution is a result of mother nature getting rid of those who aren’t fit to survive much like a natural filter. Picture Mother Nature like a metaphorical Brita water dispenser lol. A few years ago the National Academy of Sciences added fuel to the debate that humans are still evolving. Their findings include that for the past 5,000 years our brains have been getting smaller. They also saw a pattern of genetics in having children at younger ages along having large families than we have before. The scientists studied the records of nearly 6,000 Finns born between 1760 and 1849 which has information on births, deaths, marriages and economic status.

They used the data to compare humans patterns of survival and reproduction against other animals living in the same region. “Studying evolution requires large sample sizes with individual-based data covering the entire life span of each born person,” said researcher Virpi Lummaa at the University of Sheffield in England.The researchers found that humans continued to evolve just like other species and agriculture became a driving force in this process when taking into consideration survival to adulthood, access to mates, mating success and fertility per mate.

Some instances of evolution are not all bold permutations as much as you might think. The notion of drinking milk doesn’t strike you as a radical mutant change like growing a third arm, but when you take into consideration that the ability to digest lactose didn’t last long after being breastfed initially is a feat in itself. It was until we domesticated cows and used their milk that for nourishment that our genes began to change to make it easier for digestion. A study in 2006 shows that as early as 3,000 years ago in East Africa. Now 95% of Northern European descendants carry the gene that allows for milk digestion.

Another  evolutionary invention that is becoming no longer useful is our wisdom teeth. They originally were used for chewing roots, nuts and leaves. The wisdom tooth was useful when humans had a much larger jaw for easier chewing. Much like the appendix there is really no use for the wisdom tooth since we have utensils for our food and also now even 35% of the population is said to be born without them and will eventually phase out completely.

Here’s another instance that evolution is having a hand in that within the last 40,000 years humans have developed over 1,800 genes that are used for fighting off diseases like malaria. Researchers found that Africans as well as those in the city are producing genetic variants to fight off diseases like malaria, tuberculosis and leprosy. “This seems to be an elegant example of evolution in action,” says Dr. Ian Barnes from the School of Biological Sciences at Royal Holloway. “It flags up the importance of a very recent aspect of our evolution as a species, the development of cities as a selective force.”

I talked a little earlier about our brains are also getting smaller. It seems for the past 30,000 years our brains have decreased in volume from 1,500 cubic centimeters to 1,350 cubic centimeters or the size of a tennis ball. The reasoning is one argument that has the science world split down the middle. One side suggest that our brain becoming smaller is happening because we are becoming dumber. The correlation is that having a big brain means having more knowledge to process. The flip side to this argument is that our brains are becoming smaller because our brains are becoming more efficient, almost like a new model of  car coming out decades after the original model. Picture the a 1967 classic Camaro and now look at the 2014 Camaro. While the older model works fine and can handle transportation needs, the 2014 version is sleeker, more fuel-efficient has better sound quality and even the color is brighter. It could be the same thing with the human brain. This researchers also believe aggressive behavior will also decrease.

Up until 10,000 years ago all humans had brown eyes, a mutation happened turning some humans eyes blue. It’s not clear why this happened, but researchers have tied in that males find blue eyes in women compared to women with brown eyes. Also can you believe breaking down starch is a sign of evolving among humans. AMY1 a gene for amylase is an enzyme the breaks down starchy foods like bread glucose which can be transformed into energy. Those with a higher count of AMY1 in the genome are able to breakdown more starch than those with lower counts. Regions where starchy food consumption is high and a staple are also the same regions where individuals have higher AMY1. Places such  as Japan, USA and Europe historically have been higher in the AMY1 genome because of the higher consumption of starches. Certain places in Africa where the people hunt for food and don’t usually eat starchy foods have lower AMY1 copy numbers.

One last sign that we have evolved and are still evolving is the findings of a little girl who had  fifth digit on her hand. Researchers found a little pinky bone or the distal phalanx of the fifth digit. The bones and DNA came from a girl in Siberia from Deniscova Cave and what maks this find interesting is that it came from a group of that is unlike Neanderthals and unlike modern humans. It’s a population totally new to us. Some of this population still lives today according to scientists and have remained in regions like the Austrlian aboriginal peoples, the islands of New Guinea, Melanesia and the Southeast part of the Asian continent.

 

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Comments
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  2. Raul says:

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