Why hominins evolved in Africa?
Bonjour folks, In this post of scientific revelation we will discuss how and why hominins evolved in Africa. This is a topic of amazement. Why the development of hominins happened in Africa only? Clearly it had given some benefits to our ancestors so they developed and flourished here. As we know Homo erectus had first migrated out of Africa 1.8 million years ago. They were probably the ancestor of Homo floresiensis, which developed on Flores island independently. Neanderthals also had developed out of Africa from Homo heidelbergensis. Despite all these homo sapiens evolved in Africa. Our species and most of the hominin ancestors have developed in Africa. This is the very reason east Africa and South Africa are dubbed to be the birthplace of humanity. So How Africa in the truest sense turns out to be Eden garden?
There are two theories to explain our origin. First is related to DNA evidence which we can trace to find our lineage. As we know that our closest living relatives are chimpanzees. We shared a common ancestor with chimps 7 million years ago. When our lineage separated with them we both took different paths.
The second theory is related to fossils that are found in Africa. In chad, scientists have found fossils of Sahelanthropus tchadensis. It was 6 to 7 million years old Therefore it can be the hominin after the great split. They named it Toumi. In Kenya 5 million-year-old hominin Orrorin tugenensis had found. Some other prominent fossil remains have found in Africa notably the east region. Archeologists have discovered lucy (Australopithecus afarensis), Ardi (Ardipithecus ramidus) and laetoli footprints from east Africa that says a lot about our origin.
We come under the Homo genus and our species is sapiens means wise man. We are part of the Hominini tribe that also have pan genus under it. Pan is the genus of chimps. We come under the Homininae subfamily that has Hominini and the gorillini tribe under it. As you have already guessed right gorilla is part of the Gorillini tribe. Hominidae is our family which is commonly known as greater apes. This includes us, chimps and gorilla in one subfamily and ponginae as another subfamily.
In the hominin tree, we developed very recently between 300,000 to 200,000 years ago. The oldest fossil is of Sahelanthropus tchadensis found in chad. In the homo genus, the first species is thought to be Homo habilis. They are also known as handymen and were the first to use tools for hunting. Homo habilis eventually led to Homo erectus “upright man”. They were the first to migrate out of Africa some 1.8 million years ago. In the fossil of Homo habilis archaeologists have found big brains. Not as big as ours but significantly bigger than chimps. Homo erectus had a lean body and muscle.
The population of Homo erectus which had stranded on Flores island Indonesia developed into new homo species H. floresiensis. Homo erectus had also given rise to hedelbergensis. This species is known to bury their dead. They later evolved into Denisovans and Neanderthals. Either the African population of Homo erectus or some hybrid species of Africa had given rise to Homo sapiens. The brain size keeps on increasing after the appearance of Homo erectus. In later hominins it was similar to Homo sapiens. Some scientists deduce that after the discovery of fire hominin had cooked food that increased their brain size.
The development of great apes
As we are part of the great ape family, their development in Africa can tell us a lot about our past. According to fossils, great apes developed in Africa 20 million years ago. The fossils of Proconsul and Ekembo have found in Kenya and Uganda. Their skull and teeth resemble the later apes and they did not have tales. About 17 million years Africa’s climate started to change and it had influenced the vegetation. Forests started to disappear and grassland appeared. Food was of low quality and this situation urged the apes to migrate towards Europe which had a more favorable climate.
The paleoclimate of Africa
As written in the previous paragraph around 17 million years ago the climate of Africa was turning from rain forests supporter to savannah supporter. It was probably a high greenhouse period because Europe had forests similar to tropical regions. One thing is clear by the above sentences that apes needed to have a woody environment for growth and evolution. When Europe had better conditions apes moved out of Africa.
Around 90 million years ago when Indian plate separates itself from Madagascar and started moving towards Asia changes were bound to happen. The ape paradise started changing into temperate forests. As the natural habitat degraded species after species disappeared from Europe or traveled back to Africa.
The distribution of apes out of Africa
Around 16 million years ago the first ape emerged in fossils records. Griphopithecus’ remains have found in Germany, Slovakia, and turkey. In France, Dryopithecus and hungry Rudopithecus remains have found. Two ancient ape species Ouranapithecus and graecopithecus lived in savannah and open grassland environments. Their Remains have found in Greece and southern countries. Oreopithecus, an ancient ape had body features between monkey and ape. It used to live on Italian islands which then collided with the mainland and brought extinction.
Archaeologists have unearthed some fossils from Europe. Consequently, it made a huge fuss. Some thought maybe Europe was the cradle of humanity. For instance, they found a toothless jaw and a few teeth in Greece and Germany but they were not enough to contradict African origin. After that, researchers also discovered a 5 million-year-old footprint in Greece. It is telling us that maybe other hominins migrated before Erectus. The molar and canine found in Germany turn out to be of extinct ape likely Ouranapithecus or Dryopithecus. Read more about this debate on https://theconversation.com/the-theory-that-humans-emerged-in-africa-is-often-questioned-thats-good-for-science-86232
Other than these European species some African apes migrated to Asia. Sivapithecus was an ancient ape that had given rise to ponginae. Orrington might have evolved from this ancient species.
A genetic surprise for all of us
I had been watching many youtube videos on our lineage and genetic studies of we all are related. We have very little genetic variation. To clarify it we all are connected by a great grandmother from Africa. We share a common ancestor. That is to say, it lived just 3000 years ago. We know that DHA gets copies in every progeny from the parents. Only the favorable mutation that happened once in a while gets transferred in the future generations. This means if they are helping in survival they carry on or they perish.
If we go in a little bit of genetics every human carries 46 chromosomes from which each half is given by our parents. Due to genetic variation and mutation, the genetic print of our 3000 years old ancestor is invisible in us. These DNA strands are found in nuclei of the cell but there is another Chromosome strand that is present in the mitochondria. It has huge implications for our ancestry. When mitochondrial DNA is passed from one generation to another there is no variation because it is passed as such. This DNA comes only from the mother’s side.
If we trace back every female in everyone’s family tree from your mother to grandmother and so on, we find the most ancient mitochondrial DNA in Africa. As predicted it was traced back to one female who lives around 150,000 years ago. There must be other females around that time but only her lineage lives on and it is present in every one of us. We all are connected and Africa is or origin.
And the story goes on…
After lots of research and fossil evidence, we came to know how much similar we are on a genetic level. Either you live in the USA, Australia, Japan, or the Middle East the DNA difference is almost negligible. The fossils that have unearthed from Africa told the story of how hominin evolved and migrated all around the world. As we know that homo sapiens are the most advanced spices of genus Homo we may have derived from intra breeding.
It is a common understanding between scientists that homo species that lived in the same geographical areas had sexual intercourses. They don’t believe that between other species and us there was a reproduction barrier. We could very well reproduce fertile children. We have found neanderthal and Denisovan DNA in modern humans which proves the above point. Most of the advanced hominins so that is why we evolved there. Read these two articles for more information in the above topic Early humans did not developed.., and no single birthplace for mankind…
There are many things to consider that may be runaway European apes had evolved in modern ape. We are certain that there are other species and genus left to discover. As we will do more research things will be clearer for us to see our past again.