WHY TO KNOW ABOUT HUMAN EVOLUTION?

 

WHY DO WE NEED TO KNOW ABOUT HUMAN EVOLUTION? 

 

Who does not want to know about how we evolved, where we came from, how are we related to other living beings in the world, and many such things? Evolution explains all these for us. But there are cynics among us who do not believe in the scientific explanation of  evolution, or ignore it by saying, “why bother to know about evolution? It does not affect our daily life! Etc.," 

Before proceeding further, it is imperative that we address these cynics and reiterate why it is beneficial for us to know about evolution as a whole, and human evolution in particular. 

From an early age we start wondering where we come from. The amazing array of fossils that have been found in Africa, Asia, and Europe tell us  about our evolutionary lineage from Australopithecus to early Homo sapiens and also the different species that branched off in between. The fossil record reveals the huge morphological changes that distinguish us from other great apes, when we began walking upright, and when our brain size increased, and so on. 

Understanding Evolution Makes Life Easy

Evolution also tells us how we managed  technology with time and how we mastered it to our advantage. Who does not want to know why we do the things we do and improve the way we do? Tapping into our inherent curiosity about our history and origins is a great way to get  excited about science. Human evolution is instantly relatable. 

A modern understanding of human evolution, underpinned by natural selection,  enables us   to manipulate the physical environment to our advantage. As reflected by Beardsley in his editorial on the 200^th birth anniversary of Charles Darwin, understanding natural selection in itself opens paths to freedom (Beardsley, 2009). Having understood the broader principle of natural selection, researchers can now manipulate it to develop disease-resistant crops more easily and to improve various types of drug therapy. Thus, Darwin’s legacy daily enhances freedom from hunger and disease. As Beardsley says, “Good ideas, as well as advantageous genes, tend to spread.” 

Importantly, Darwin’s legacy has a direct bearing on how society makes public policy and even, at times, on how we choose to run our lives. Overfishing of mature adults  makes way  for smaller fish; at the same time excessive use of antibiotics leads, by natural selection, to drug resistance. A food for thought for regulators and legislators (Why Everyone Should Learn the Theory of Evolution. Scientific American, January 1, 2009)! 

Knowledge Of Evolution Helps Us to Fight Diseases

Understanding evolution helps us solve biological problems that impact our lives. There are excellent examples of this in the field of medicine. To stay one step ahead of pathogenic diseases, researchers try to understand the evolutionary patterns of disease-causing organisms and virus-host relationship. To control hereditary diseases in people, researchers study the evolutionary histories of the disease-causing genes. In these ways, a knowledge of evolution can improve the quality of human life. 

Since the time Randolph Nesse and George Williams published their book, 'Why We Get Sick: The New Science of Darwinian Medicine', many have been convinced that a Darwinian perspective on disease  can provide insights into many clinical conditions. For instance, Williams refers to  the suggestions of the British biologist J.B.S. Haldane that the high frequency of genetic blood diseases, sickle-cell anaemia, and thalassaemia in some human populations,  may be linked to malaria resistance. It was a remarkable insight, but it took a long time to validate (Williams, 2003). Sickle cell anaemia is an inherited red blood cell disorder in which there are not enough healthy red blood cells to carry oxygen throughout the body. Sickle cell disease itself is very severe but the affected people  live normal lives and are far less likely to develop malaria, if the disease is not active. 

Malaria is not the only such case.  There are people whose genes make them more resistant to HIV/Aids. As the technology for analysing genes and their variability advances, more examples of genetic variation in the face of disease are likely to emerge.  As rightly stated by Williams (2003), knowing about the different forms of relative resistance to a disease might also lead to new ways of managing it.

 Evolution may also provide an insight into many modern diseases, such as obesity, diabetes and autoimmune disorders, breast cancer, hip fracture, and depression, which come about partly  because of the mismatch between our genes and an environment that changes more quickly than human genomes can evolve. According to many, the change from  ancient hunter-gatherer environments to the  present-day environments may be a reason for these. Understanding this disparity may help convince us to make a change in diet and life-style to better conform to the demands of a genetic heritage. 

From around the late 70s molecular studies introduced new understanding of the  abnormalities or differences that  explain the cause of diseases or variations among the ethnic groups (Mukhopadhyay, 2016). Evidence has suggested that different illnesses, diseases, and other defects as well as other benefits can be linked to the differences of gene or in gene expression among humans. Studies have revealed  that some modern humans share genes with archaic humans, namely the Homo neanderthalensis and Denisovans.  As it has also been found that some genes inherited from Neanderthals are advantageous for the survival of humans  in colder places while some other genes are associated with higher risk of diabetes and increased rate of male infertility (Mukhopadhyay, 2016), gene sharing assumes importance in tackling these issues. The study of the haplotype facilitates tracing of any particular disease or disorder that have been inherited from a particular parent (Haplotype refers to the set of genes inherited from a single parent). 

The interaction of man with viral agents was possibly a key factor shaping human evolution, culture and civilization from its outset. Historical records on specific diseases of ancient humans are scant and fragmentary. However,  in some instances, palaeopathologists were able to identify certain diseases,  such as tuberculosis, that leave lesions in bones of primitive man (Leal and  Zanotto, 2000).  It is conceivable that during the dispersal out of Africa through all regions of the Earth, pathogens capable of causing persistent infections were possibly carried along. As further noted by Leal and Zanotto (2000),  many of the modern diseases such as measles, influenza, dengue, etc.,  were perhaps  not widespread until the Neolithic period, possibly because  till then the human population size and density were not enough to maintain sustained epidemics. 

Evolution explains aspects of the human condition that we already know about, but that are puzzling. One such condition is anxiety. Al-Shawaf (2021) explains anxiety in light of evolution. According to him, anxiety is related to how our brains evolved. When it comes to detecting danger, the brain possibly could not differentiate between a real threat or a threat that was not really there. Of these two possible errors, failing to detect a real threat was much more costly. So, our anxiety mechanisms have evolved to be what he called, “adaptively biased” towards  of the safer error, i.e., toward false alarms. Just like smoke detector, a systematic bias toward false alarms minimizes the likelihood of the more catastrophic error.

 Evolution and Humility

Echoing the sentiments of  Lauren Seville (2016), we reaffirm that learning about human evolution is a lens through which  people in general can get connected to the world, to the terra firma. We are primates, just like the living animals we call apes and monkeys, though we have our own evolutionary path, and a really big brain. We are like other animals who are best adapted to their environment,  surviving long enough to reproduce and pass their genes onto their offspring. Thus, our unique human-defining traits do not make us better than our other primate relative. We are just different!

 If we understand our evolutionary place in the world, it becomes easier to accept the idea that we are no better than the organisms we share the planet with. Looking back to the travails through which the humans passed through to evolve into what we are today only reinforces the fact that at each stage we gained something from our predecessors and contemporaries. We are a unique  product of a magnificent natural process and cannot differentiate one another on the basis of man-made classification of race, caste, or religion. In this way, studying human evolution is humbling and in this day and age, we all need a little humility.

 References -

Al-Shawaf, L., 2021.  Evolution Explains Puzzling Aspects of the Human Mind.
https://www.psychologytoday.com › intl › blog. 11-Jul-2021

Beardsley, T., M., 2009. The Individual Benefits of Evolution.   BioScience,  Vol. 59 No. 4 • 275  April 2009 doi:10.1525/bio.2009.59.4.1

Leal, E. S., and  Zanotto, P. M. A., 2000. Viral Diseases and Human Evolution. Mem Inst Oswaldo Cruz, Rio de Janeiro, Vol. 95, Suppl. I: 193-200, 2000

Saville, L., 2016. The Importance of Teaching Human Evolution. National Centre for Science Education. July 19, 2016.

Williams, N.,· 2003 Evolution and disease.  Current Biology Vol 13 No 1. https://doi.org/10.1016/S0960-9822(02)01375-1