The development of Homo sapiens……

The span of Hominin history

To make thongs clearer, 13.7 billion years ago there was a big bang somewhere in nothingness. It had given birth to space, time, matter, energy, and physics. Approximately 5 billion years ago from the solar system galactic cloud, our sun had born. Sun had taken 99.9% mass and rest of the mass distributed among planets. As you know because of gravity planets started to revolve around the sun in orbits. Chunks and debris of space had turned into compacted planets. About 4.8 billion years ago earth came into the picture.

Homo and Hominin

There is a difference between homo our genus and hominin. Hominin explains animals that are more similar to us than chimps. Homo is a part of the whole hominin group which also has other genus and species inside them. Other genus and species of hominin groups are different from Homo genus with more apes like features. On the other hand, the Homo genus with its famous members including Neanderthals and Homo erectus shared the same body structure, brains, and tools. They used to live in groups as a hunter-gatherer. They had sophisticated tools for hunting. Now let’s get in the past to understand other species and the mutation that eventually lead to us.

The earliest hominin species

Humans are closely related to chimpanzees. According to fossil studies, humans and chimps shared a common ancestor 7 million years ago. Approximately 7 million years ago first hominin sahelanthropus tchadensis evolved which had teeth smaller than other apes. Smaller teeth explain that their eating habits must have changed. Small compact teethes suggest nuts, fruits, and meat in the diet. Apes have sharp and long teeth that help them in chewing leaves and branches. 6.5 To 7 million years ago another species orrorin tugenesis lived in eastern Africa. It had thigh bone very similar to the human femur which suggested upright walking. The first fossil remains of orrorin tugenesis found in Kenya in 2003. It was dubbed “the millennium man”.

The onset of the homo genus

Around the same 2 million years ago time first and foremost member of our genus was found. Fossil of Homo habilis was found in Ethiopia with first tolls. They were either used for hunting or other purposes. Researchers have found remains of Homo erectus and Homo ergaster in western Asia and eastern Africa respectively. They are dated back to 2 million years old. Homo erectus probably has migrated out of Africa around this time. It had a human-like brain structure with an average 1,000 cc (546- 1,251 cc). We have found Homo neanderthalensis remains in Europe. They used to had larger brain than ours. Homo sapiens were evolved in eastern Africa around 200,000 to 150,000 years ago.

The theory of evolution

The Piltdown man hoax

In 1912 an archaeologist Charles Dawson contacted the British museum and presented them human skull fragments which he collected from Piltdown in England. After returning to the site they found some animal fossils and those helped them in determining the age of the fossil, 2.58 million years ago. They found a lower jaw on the site and its molar teeth were similar to humans. One sharp canine discovered resembles ape-like. This fossil human had a large brain and it was Eureka. A human ancestor Eoanthropus dawsoni, our missing link was found.

Species of homo Genus

To understand our species tree we have to study when and how our genus separated itself from other hominins. It is a normal acceptance that the homo genus has developed from the Australopithecus genus. The first members of homo which have developed from Australopithecus were either Homo habilis or Homo erectus. There is an ongoing debate that who made firsts modern tools H. habilis or H. erectus. The oldest member of the homo genus is H. habilis which used to live in northern Africa from 2.4 to 1.5 years ago. Homo erectus was the first species who migrated out of Africa. We have found its earliest known fossil (1.8 million years old) in Damnisi, Georgia.

Upright man and Neanderthal man

The Homo erectus ranges comprise of Asia and the Middle East. They are also considered the most successful homo species that lived for 2 million years. Homo neanderthalensis also commonly called Neanderthals lived in Europe from Western Europe to as far as the middle east. They live from 2.6 to 11000 years ago. Fossil evidence suggested that Homo erectus were upright walkers as the name describe. They had a large brain with average 1000 cc very near to our brain. They had a large body with optimum muscle mass. Neanderthals had darkened skin which in later years turned fair. Neanderthals also had developed blue eyes and they were accustomed to living in harsh winters of Europe. The cranium capacity (cc) of their brain was 1500 cc.

The hobbit

Homo floresiensis made a sensation when it discovered on Flores island of Indonesia. This species has a pet name “The Hobbit”.

Other species in the development of homo sapiens

Some other species of Homo includes Homo Naledi found in South Africa, at rising star cave, the cradle of humankind. This species had lived approximately 300,000 years ago. In Altai cave, Siberia Homo Denisova fossils were found. Studied shows they lived 200,000 years ago.

Our family tree

For a long time, it was thinking that we are not part of any group of the animal kingdom. We don’t have relatives and cousins and parents but know fossils and DNA studies have proved that we also have a family to count on. The development of Homo sapiens has happened through a long line of lineage. We come under the Hominini tribe which also includes pan, the genus of the chimpanzee. Our sister tribe is Gorillini ex. gorilla and subfamily is homininae. Our family is Hominidae means great apes. It also includes the sister family Hylobatidae lesser apes. we belong to order primates.

The development of Bipedalism

Bipedalism is the trait-associated uniquely with humans as we are the only animal who walks on two legs. On the way to the development of homo sapiens, we have learned to walk on two legs a long time ago. Birds also walk on two legs but their anatomy is different from us because they have wings on forearms so our comparison cannot be done. Up until this time Bipedalism is the main trait that we look in species to include them as Hominin.

The science behind upright walking

It is clear that a large brain developed a lot later and upright walking was present in a lot of other genera. We know that use of language and sophisticated tools for hunting are also hominin traits. But animals also possess. For instance animals like ape family and dolphins also use a wide variety of sounds for communication. Some members of the ape family have found using resources like stone or sticks for gathering food. But walking on two feet and balancing the body is something only humans can do.

The savannah hypothesis

According to fossil evidence around 10 million years ago large parts of eastern and North Africa were covered in lush green forests. But then land in east Africa began to rise due to tectonic plate movements. Rising land had stooped the rain clouds from the Indian ocean. Rainfall in the region became less and rainforest turned into the savannah. In savannah, hominin had to walk a few km to get to another patch of trees so it was better to walk on two legs.

And the research goes on…

We need time to discover how many species are out there. How interbreeding and co-surviving had paved the way for the development of us, homo sapiens. Studies have found 4% of Neanderthal DNA in some populations of Europe. In the same way, we have Denisova DNA in China and Korea. This had proved that there was occasional interbreeding between many co-living species. As the research and fossil searching goes on we will likely know more about how we have developed into homo sapiens.

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Aayushi Tiwari

Aayushi Tiwari

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Hey everyone. I am a bibliophile and love writing. I am trying to sharpen my hobby of writing regularly. I am always up for new things to learn.