4 The Human Flood
This looks at how mankind reacted to other plants and animals and significantly changed the world as they spread out of Africa. This lecture deals with the vast changes that Homo Sapiens made and how it did it.
Earlier hominids did not significantly change the ecology or cross the open sea. They lived entirely on the afro-asian land mass. only breaching close by islands that could be reached bt swimming simple flotation or periodic land bridges. Homo Sapiens did manage to cross the open sea yo find land not easily visible. The eco systems on these areas Australia thee Americas and Madagascar had developed entirely separately and differently. This unified the whole planet by moving plants and animals around and by exterminating other species. 45,000 years ago homo sapiens got to Australia crossing open sea. There they discovered and adapted to a totally new ecological system that had evolved separately to be very different.
The answer is that the Indonesians had developed a seafaring society for fishing and moving between the islands in an archipelago. This was based on knowledge and technology not on physical evolution as did animals before this period when they changed their major habitat. It is also a very significant event and provides vital information because it shows how man had become the top species (predator) on the earth.
The settlers of Australia transformed the Australian Ecosystem. There were giant Kangaroos, giant Koalas and Giant flightless birds bigger than Ostriches giant lizards and snakes and the largest creature of all the diprotodon weighing 2.5 tons there were also marsupial lions as the top predator. 23 out of 24 large species rapidly became extinct during this period the only exception is the red kangaroo. There has been suggestions that climate change caused it. There is also through evidence that mankind did this.
There ate two explanations for this large marsupial animals breed slowly only having one baby with a long gestation and dependancy period hunting killed enough to overcome the birth rate. The second is that homo sapiens was not recognised as a potentially dangerous predator and so they were much easier to hunt. In Africa hunting skills developed slowly and animals had time to learn and adapt to avoid them.
Also "fire agriculture" That using fire to clear dense forest land to create open grassland in which it is easier to hunt and create traps using land features This changed the ecosystem and created open grasslands this also encouraged the eucalyptus trees which use fire to help their propagation as a survivor and a precursor plant after a forest fire. The climate change that did happen it just helped them by putting the ecosystem under stress. This was the first example of Mankind affecting the earth’s ecosystem and leaving a permanent and indelible mark on the archeology of the earth. The affect on Homo sapiens on The americas was even greater.
This section looks at other major ecological changes wrought by early man when they reached the continent of America around 16,000 years ago. This was very much larger than The invasion of Australia
Homo Sapiens crossed from Asia using a land bridge during a cold period with low sea level and spread over the whole of North and South America in around 2000 years! This probably happened while they were following the herds of nomadic mammoths and reindeer which would cover the whole of this area.
They adjusted rapidly to a vast array of climates of these large continents and were detectable at the tip of south america about 10,000 years ago. They changed the fauna very markedly there were many very different animals nearly all the large species disappeared many genera were wiped out including the native American horses. In this period 34 of 47 Genera in North America and 50 out of 60 Genera in South America became extinct each of these Genera contained several separate species! These extinctions are already one the largest extinctions outside of the major geological extinctions. over a period of 1000-2000 years! These genera had survived through many climate change episodes so climate could not have caused this mass extinction. Many smaller mammals and parasites died out due to the effect of mankind. Humankind is the most dangerous animal on the earth by far. Globally during this period before man there were 200 genera of large animals only 100 genera were left at the time of the agricultural revolution. These extinctions and ecological changes have continued since the agricultural revolution which created a second wave of extinctions. This also happened in Madagascar after the first human farmers arrived in AD500! The pattern follows with every isolated spot humans inhabit. A large variety of large animals disappears and a second wave of extinction follows the domination of human monoculture agriculture the whole ecology changes.
We have Never lived in harmony with Nature. This is not a modern phenomenon! Mankind destroys anything that gets in its way. We are now entering a third wave with of Extinctions with our industrialisation and climate change!
Asteroid strike and Climate disaster has caused mass extinctions in the past but mankind has already been responsible for extinctions on this scale. Over the last hundred years mankind has raided the oceans for large animals and fish. Unlike the Biblical story of Noah and the flood where Noah took all the animals in his ark to protect them mankind only recruits those animals and plants that will serve him and be amenable to his controls and kills off the rest!
The next lecture will discuss this domestication of plants and animals in the Agricultural revolution.
It will also discuss the high personal price that mankind has paid for doing this!
return to 1 Index page Sapiens A Brief History of Humankind
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