Evidence suggests that Homo sapiens’ initial population originated in east Africa – though some think we may have originated in southern Africa, and others from northwest Africa.  It is believed this occurred about 300,000 years ago.  The first humans were hunter gathers and fed primarily on small prey and plants – we are omnivorous.  With the development of stone tools early humans could feed on larger prey and take a different position in the food chain.

Populations of all creatures increase and decrease due to the number of births, deaths, immigration, and emigration within their populations (we will focus more on the human population in the next article).  As populations grow, competition for needed resources increases.  One response to this competition is dispersal – the movement of members of a population to a new location where resources can be found.  This is different than migration in that in dispersal the members do not return – they have moved away.

Evidence suggests that humans began dispersing from Africa very early.  It was thought at first humans did move into southern Africa, but there was a mass movement north into the Middle East.  From here humans began to move east along southern Asia to India and beyond to southeast Asia.  There is evidence of “island hopping” as they made their way across Indonesia and eventually to Australia.  Later groups from southern Asia dispersed north into northern Asia.  From here there were two movements – one into Europe and another across an exposed landmass connecting Asia to North America – remember the Earth continues to go through slow change over time.  At one time there was a land bridge that connected the two continents and allowed humans, and other species, to cross.  Humans began to spread across North America and – with the emergence of a land bridge in Central America – reached South America.  There are those who also believe – based on language and culture – some Polynesian humans reached South America by boat.  To test this idea an expedition sailed from Polynesia to South America on a balsa wood raft called Kon Tiki in the 1940s.  This same team attempted to sail from Africa to South America to show this could have been a dispersal route as well using boat materials from that time – but that expedition failed.  However they reached South America, they did – and humans had dispersed to cover all landmasses except Antarctica.  This still holds true – there are no native populations of humans on the Antarctic continent – only visitors.

Within each region of the planet where humans have inhabited, we find physical and cultural differences.  The physical difference – which we call races today – were adaptations to the environment where they lived.  There languages, tools and building practices, songs and instruments, and religions were all born from the area where they lived.  Many of these populations were isolated from each other – and so their cultures became quite different.  As these populations grew and expanded, they would come in contact with each other.  Many times, these different cultures, or tribes, would fight for resources and space.  As our imaginations and technologies grew, some cultures were able to cover more territory and conflicts increased.

Today there are about 8 billion humans on the planet.  Some areas are more densely populated than others.  Based on the website Worldometer – we are gaining a new human almost every second.

Over history, most species have had a slower population growth – if growing at all.  Numbers are kept under control by predators, disease, and environmental conditions that impede, or restrict, reproduction.  But not with humans.  In the next article we will look closer at the cause of the human population explosion.

References

Pavid, K. 2018. Rethinking Our Human Origins in Africa. Science News. Natural History Museum. https://www.nhm.ac.uk/discover/news/2018/july/the-way-we-think-about-the-first-modern-humans-in-africa.html.

Pobinar, B. 2013. Evidence for Meat-eating by Early Humans. Nature Education Knowledge. (46)1. https://www.nature.com/scitable/knowledge/library/evidence-for-meat-eating-by-early-humans-103874273/#:~:text=Tooth%20morphology%20and%20dental%20microwear,Ungar%202000%3B%20Luca%20et%20al..

Dorey, F., Blaxland, B. 2020. The First Migrants Out of Africa. Australian Museum. https://australian.museum/learn/science/human-evolution/the-first-migrations-out-of-africa/.

Kon Tiki Expedition. Wikipedia. https://en.wikipedia.org/wiki/Kon-Tiki_expedition.

Worldometer. https://www.worldometers.info/world-population/.

1