Grass, Ruminants and the evolution of humans

In my previous piece I explored evidence of how grasslands and its attendant fauna have come to dominate the earths ecosystems from approx 15 Myrs ago.

There is conflicting evidence for the evolution of both the biosphere and the climate since then, this evolution has been studied extensively, but firm conclusions about causality are lacking. I have a theory which I believe best fits the facts but for which evidence is both anecdotal and conflicting but nevertheless has the best explanation for the current pseudo crisis.

Grasslands have developed over the last 20 Myrs, with an attendant faunal complex to create a dominant ecosystem. This dominance is mainly due to the way in which the sum of the parts is greater than the whole.

The ecosystem is comprised of grasses, grazers and hunters. The evolution of large herds of grazing animals in a mutualistic system with the grasslands created an opportunity for the development of pack hunting carnivores, this development is reasonably well documented for individual species, wolves, lions hyenas etc.

About 7 Myrs ago primates descended from the trees, and although omnivorous entered this ecosystem, and the rest as they say is history. Humans developed to both use and dominate this ecosystem. Human evolution has occurred in tandem with the development of this system and a cooling climate. It can be no accident that the principle foods of humans are grasses (wheat , rice etc) and grazing animal products (meat, milk etc). Indeed these products not only sustain us but are part of our psyche, witness the western worlds love of lawns, and the eastern world and bamboo.

The development of humans of course involved elements which had not previously occurred i.e. intelligence and the use of tools including fire. Indeed fire and the humans use of it increased the dominance of this ecosystem, see previous posts.

Many modern scientists and commentators point to the human abuse of this ecosystem, and the climate, but I contend that serendipitously or not the principle reason for the evolution of humans was to reverse the downward trend of co2, and end the ice ages. The final link in this chain, which started with the spread of humans across all land masses over the last 30,000 years, was the industrial revolution. The vast increase in CO2 over the last 300 yrs was partly in response to an incipient ice age. This and previous human interventions in the climate over the Holocene can be viewed as a biological environmental control mechanism (biological pump), with the sole purpose of stabilising the climate. This was both necessary and also a result of our evolution and genetic programming.

My final observation in this piece is that although common belief is that weather is more volatile today, the paleoclimatic data suggests the climate has been more stable over the last 15,000 yrs than in the previous 1 Myrs, this is almost certainly been caused by the growing influence of the grassland biome. This coupled with the observation that stone age humans survived much more extreme climates than we currently do, should mean that the future is rosier than the doom mongers are predicting.

As another favoured blog of mine often says, ‘keep calm and enjoy the interglacial’



About madmikedavies

Retired Communications Engineer, living in Portugal. Interests are Cosmology, Earth Sciences, Organic farming, Climatology, Football, Golf, Birdwatching, and Dogs
This entry was posted in Climate change, evolution and tagged , , . Bookmark the permalink.

4 Responses to Grass, Ruminants and the evolution of humans

  1. Sam Andrews says:

    Great insight! …since I mostly agree… Have you read Ruddiman’s, Plows, Plagues, and Petroleum, about how we “took control of climate” millennia ago? -Sam A. M.


    • Sam,
      Yes, although I have only read a summary, I did communicate some of my original ideas to Bill Ruddiman over 4 years ago. My belief is that intelligence in part evolved to oppose the then cooling of the earth. Have you read any of my earlier musings



  2. Pingback: Grass, Ruminants and the evolution of humans | Gaia Gazette

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