How we came into existence has substantially been a topic of debate for generations. Since science was not appealing enough before the 18th Century, people following different cultures had their own ideology and explanation for origin of man. While some of these are still existent today, majority of us now believe in the scientific explanation. Science regards evolution, based on Charles Darwin’s theory, as the primary explanation for life as we see it today.
Evolution simply means the change in characteristics of a species over several generations. People rarely believe that we have not been same forever. Darwin cited “Natural Selection”, Individuals with best-suited characteristics for survival will live while others will perish, for explaining his theory of change in characteristics. The unambiguous inference is that modern humans (we) are not a duplicate of what humans were like a million years ago. Lack of ability to pass on genetic material without variation explains this transition.
So how do know about the past? Paleontology (Study of fossils) gives us a perception of how modern humans evolved. Everyone in their slightest notion are aware that we share our ancestry with Chimpanzees. But not everyone knows that transition took place for millions of years to constitute our current form. It is believed that somewhere around 7 million years ago, the evolutionary divergence took place to constitute the origin of man.
- The major achievement took place when in 1974 fossils of an almost complete Australopithecus afarensis named “Lucy” were found in Ethiopia (East Africa). It was concluded as an early hominid that roamed the earth on two legs (Bipedalism) 3-4 million years ago. It had brain size and biology similar to apes. Although this genus is extinct, it revealed adaptation towards a terrestrial lifestyle.
- Homo habilis is widely accepted as the first human. Their first fossils were found in the late 1950s. They were 40 inches in height, had ape-like arms, made stone tools and lived around 2 million years ago.
- However the most prominent of the Homo genus was Homo erectus. The first fossils were found in 1891. They were the first to migrate out of Africa to modern-day China and Indonesia. They had an upright body and a decent sized brain. It is believed that they were the first to control fire, scare predators away, and lived from about 2 million to 110,000 years ago.
- The closest to modern humans were Neanderthals. They existed in western Eurasia from 400,000 to 40,000 years ago. They were 5 feet long and had larger brains than modern-day humans. They buried the dead, killed at a distance, had sophisticated culture, clothing, shelter, tools and were capable of making art. Homo sapiens (we) came into existence around 300,000 years ago.
WHY HOMO SAPIENS SURVIVED?
It is clear that not one human has walked on earth. Most scientists recognize some 15 to 20 different species of early humans. Further, it is widely accepted that there was a time when we lived along with at least six of our cousins. So, where did they disappear? Why is it that only Homo sapiens survived? What made our species so special?
It is imperative to note that human evolution was not a linear process rather it was a web. Interbreeding took place extensively. From the time period of Neanderthal extinction it is understood that both climate and Homo sapiens had a crucial role in it. Abrupt climate shift and disease spread was accompanied by a time when Homo sapiens grew stronger. Some researchers believe extensive interbreeding between Neanderthal and Homo sapiens was the prominent factor while others believe the theory of competition between these species. While both these factors can be crucial, the biggest challenge to date has been to sort out the dominant factor that led to life as we see it today.
With human evolution, the understanding of how humans lived earlier has also evolved over time. The theory of the mid-80s contradicts the late 80s, the late 80s contradict the 90s and 90s contradict 2000s. Two models are put forward today. The “Out of Africa” model and the “Multi-Regional” model. The former is widely accepted, according to it Homo sapiens evolved in Africa and a mass exodus took place 60,000 years ago to different parts of the world. According to the latter, Homo sapiens evolved in multiple places rather than a single site. The theory of origin of man is bound to change in future as more and more traces of the past are revealed.
For more than 99% of human history, life was entirely different. Multiple revolutions is the result of life as we see it today. Bipedalism developed millions of years ago, but the large and complex brain, the ability to communicate through a language, complex symbolic expression developed more recently. It is believed that behaviorally modern humans evolved 70,000 years ago. We had an explosion in innovation of tools and weapons around 50,000 years ago. Agriculture began 12,000 years ago. With agriculture came civilization followed by villages, cities, kingdoms and empires. Scientific revolution began 500 years ago, followed by the Industrial revolution 200 years ago. The Internet came to a generation ago and major technological advancement was not made until the 21st Century. We preserved our knowledge and expanded on past knowledge. This the reason why we are successful than other species. In simple terms, life, as we see it today, would not have been possible if the fire was not controlled a million years ago and stone tools were not made half a million years ago. Those negligible innovations in today’s sense are the root of all the advancement that followed.
The origin of man has always been subjected to doubts and debates for generations. After all, it is not possible to peak in the past and know everything. Speculation on the origin of man might go on for a long time before we come to a scientific conclusion. It may well be that we may never know the exact truth. Despite this, a major accomplishment in the recent past has helped us to understand who we are and where do we come from. Every part of our body is a result of millions of years of evolution. It is interesting that even today, many of us carry a slight fraction of DNA from archaic Neanderthal and Denisovan ancestors. This may well be the reason why we are able to tackle modern-day diseases and adapt to new environments. It is important that we cherish everything we have today because, for 99% of human existence, none of it was ever available.