Impact of Evolution On Human Existence

Humans are perhaps the most advanced organisms that nature has ever created (well according to some sects and cults humans are God's best creation though). Being the organisms as humans are,  they possess a well-developed organ system suited to adapt any freaking climates that can virtually exist. The best part regarding human beings is that no other animal is as social and rational as they are. Sometimes some questions about rationality and socialism may arise, which are not our concern right now. We will be considering the scientific aspects of the complexities of human beings' physiological and psychological properties.

From time immemorial the origin of human existence, the evolution of human being and the effect of evolution on human existence have been a hot topic. Especially in the late 1900s, any new findings about human evolution were sold like hotcakes. Well, there are enough reasons why they did the same. As already mentioned above, the human body is by far the most complex system that mother nature has to offer, it's each and every function is tightly regulated with a failure rate of almost zero. The search, for this reason, influenced a lot of scientists and scholars to take an interest in this manner.

With the advent of Molecular Biology as a science and also the advancement of Palaeontology lead to a massive boost to the research work of origin of human beings. According to some scientists,  humans or more specifically speaking the modern-day humans (Homo sapiens sapiens) have evolved from the great apes mainly orangutans (Pongo pygmaeus). How is this possible? How is the arboreal lifestyle completely transformed into a terrestrial lifestyle? How has herbivorous nutrition transformed into an omnivorous one? These were a few of the many questions that hit the researchers at that time.

The study of fossil records reveals the following discrimination between "us" and "them". Their cranial capacity was about 375 cc which was a bit more than one-fourth of ours. They had both of their hallux ( thumb of feet) and Pollex (thumb of hand) opposing to each other, perfectly suited for arboreal life and gripping of branches, facilitating in tree climbing. In our case, we only have the Pollex opposing. They had their vermiform appendix fully active (more than 13 cm. in length)which is believed to harbor cellulolytic (cellulose-degrading) bacteriae, chiefly because of frugivorous and herbivorous diet, unlike us (whose appendix is less than 9 cm.), because of an omnivorous diet. Bipedal locomotion is favored in us due to three curvatures in the spine, allowing erect standing and they could not do that because they don't possess any curvature in the spine. The presence of true body hair (lanugo) in them protects their skin from harsh climate conditions. Rather we have much sparser body hairs as we wear clothes.

These great changes and variations were not achieved in a single day but these were the manifestation of several hundreds of million years. Yes, this is what we call "EVOLUTION".

Now let's get into the bombastic word Evolution.

What basically is Evolution? Evolution is the accumulation of certain small heritable changes in the genome of an individual as and when favored by nature, more precisely known as "Natural Selection" finally leads to speciation (or the emergence of a completely new species) one fine morning!!! Natural Selection deals with the use or disuse of certain structures like the vermiform appendix which is vestigial in us.

                                                                                                 Credit: Pinterest

Molecular analysis can explain human evolution in a better way. 18S rRNA sequencing revealed that modern-day humans are the true descendants of the great apes. The most fascinating thing is that the orangutans and the other great apes have 2n=48 chromosomes (i.e. haploid set n= 24) while humans have 2n=46 chromosomes (i.e. haploid set n= 23). One theory behind this is that a greater parts of the last homologous pair might have undergone Robertsonian Translocational chromosomal aberration, rather a homozygous translocation (occurring in both the homologs) giving rise to a novel homologous pair, wherein the homologs are double the size of the last pair and two pairs of homologs which are extremely small and contain nonessential genes and were lost during subsequent cell divisions. Due to the position effect, certain genes could not express themselves and hence got silenced, whereas some other novel genes expressed themselves which were unable to do the same in our so-called ancestors, exhibiting new phenotypes.

Well, this was not a one-day thing. It took millions and millions of years to give rise to a novel homologous pair finally give rise to modern-day human. Probably in the time yet to come more of these aberrations may arise giving rise to a more advanced system which might be true Superhumans just like the AVENGERS!!

Acknowledgements : Inspiration and theories have been collected from my friend, philosopher and guide Mr. Arindam Dey.

Author : Kaustav Mitra