Monday, 11 April 2011

Book Review

'Here On Earth: A new beginning' by Tim Flannery, pub. Allen Lane, 2010, (ISBN: 978-1-846-14396-0), 316 pp., £14.99

The Sun, together with its attendant planets, including the Earth, condensed out of a cosmic cloud of gas and dust 4.5 billion years ago. Within a billion years, as the author of this book expresses it: “parts of [the Earth’s] crust had begun to organise into life”. Eventually there appeared microscopic plants and bacteria which split the CO2 rich atmosphere into oxygen and carbon. They also used toxic metals, dissolved in sea water, to speed up the chemical reactions which were essential to their existence. As they died and sank to the ocean floor the toxins were taken out of circulation and concentrated into the Earth’s crust. Hence living organisms modified the planet by making the atmosphere richer in energy (oxygen is a very reactive gas) and the oceans less toxic. The stage was set for life to become more complex.

Five or six million years ago several species of upright apes (hominids) began to appear in Africa. Two million years ago one of these hominids (Homo erectus) managed to migrate out of Africa and to colonise parts of Asia and Europe. Although H. erectus developed stone tools it had a smaller brain than modern humans and appears not to have possessed language; eventually, for reasons which are not clear, it became extinct. Fifty thousand years ago one of H. erectus’s smarter relatives (H. sapiens) also migrated out of Africa. These modern humans made their way around the shores of the Indian Ocean, eventually reaching as far as Australia. Some break-away groups then gradually colonised inland Asia, Europe and the Americas. Much of this story has only recently become clear as a result of genetic studies.

The impact of human beings on the rest of the world was catastrophic. Our fire and tool using, upright ape ancestors caused havoc, wiping out the megafauna (and much else) on five continents. In northern Eurasia, for example, there once existed a place called the Mammoth Steppe. This was a dry, frigid grassland populated by mammoth, woolly rhino, bison, musk ox, giant elk and horse. It took our species a while to adapt to this region’s harsh climate but once we had done so we wiped out all of these giant beasts - basically scoffing the lot! This mass extinction, particularly the loss of the mammoths, had a profound and devastating effect on the region’s ecology. Soon after, humans arrived in North America - which promptly lost 34 genera of large mammals, followed by South America which lost 50. Today we’re just mopping up what’s left - but we are waging this on-going war against Nature war with a ferocity that our ancestors could only have dreamed of. We have drenched the land with poisons and dug up the toxic heavy metals that the ancient bacteria had buried and spread them around again. Most dangerous of all we have extracted vast quantities of fossil carbon from the Earth’s crust and burned it to form CO2 - resulting in increasing climate instability.

In this book the Australian scientist, writer and explorer, Tim Flannery looks at this long and complex story from an evolutionary perspective. He reviews the life and work of Charles Darwin and his ‘Neo-Darwinist’ successor, Richard Dawkins - who reasoned, in his book ‘The Selfish Gene’ (1976), that we and other animals are mere ‘survival machines’ whose sole purpose is to ensure the perpetuation of the genes we carry. He goes on to suggest that the theories of Darwin and Dawkins are essentially reductionist and contrasts those theories with the more ‘holistic’ views of the co-discoverer (with Darwin) of the Theory of Evolution, Alfred Russell Wallace. Flannery tells us that while Darwin, “sought enlightenment by studying smaller and smaller pieces of life’s puzzle, Wallace took on the whole, trying to make sense of life at a planetary and universal scale.” He nominates the remarkable English chemist and planetary scientist, James Lovelock as Wallace’s modern-day successor. Lovelock, you may remember, formulated the ‘Gaia Hypothesis’ which suggests that the whole planet, from the core to the fringes of space, is one vast, self-regulating ‘organism’ and that continental plates, volcanoes, the ice caps, the oceans, the atmosphere and living things all play their part in maintaining an equilibrium which allows life to flourish. What humans are doing at the moment is the equivalent of sticking a large screwdriver into the delicate works of an antique clock and stirring it around. Lovelock believes that the coming climate catastrophe will kill 90% of us.

Flannery reminds us that, at this time in our history, we humans are not just ruled by our genes but also by, what he calls, ‘mnemes’ (Dawkins calls them ‘memes’) which are, basically, “ideas which have a living reality in our brains”. Science, religion and philanthropy are all examples of mnemes and they can act for good or for ill. Darwin’s Theory of Evolution is another mneme, but so is the wilful mis-interpretation of the Darwinian ‘survival of the fittest’ concept which has often been mis-applied to human societies with disastrous consequences (Nazism or rampant, unregulated Capitalism, anyone?). Mnemes, of course, evolve far faster than genes.

Another concept which Flannery discusses is coevolution. This is natural selection triggered by interactions between living things. Throughout the history of life on Earth countless examples of coeveolution have arisen. Examples include microrrhizal fungi on the roots of trees and other plants and the relationship between the coral polyp and its algal partner. It’s an extraordinary fact that the cells which compose our bodies contain elements called mitochondria which actually power the cells. There is strong evidence that mitochondria were once free living bacteria which invaded the cells of our remote ancestors aeons ago. Incidentally, mitochondrial DNA is only transmitted through the female line and this fact was used to trace the paths that humans took out of Africa.

When considering the future of the planet and the living things (including us) which co-exist with it, Flannery invokes another duality – the competing possibilities of a ‘Medean’ future or a ‘Gaian’ one.
The palaeontologist Peter Ward has advanced the hypothesis that species will, if left unchecked, destroy themselves by exploiting their resources to the point of collapse; this is the Medea hypothesis. The other possibility is a Gaian one. Flannery suggests that our species has already evolved into a ‘superorganism’. If we survive the next couple of centuries we may possibly learn to restore the Earth. And then the planet, through her co-evolved human superorganism, would “be able to foresee malfunction, instability or other danger and act with precision.” My money is on a Medean outcome – but let’s hope that a Gaian future is not beyond the bounds of possibility and that this fine book will help to plant the Gaian mneme in the collective brain of humanity.

This is a remarkable book and if you are interested in the past, present and future of our planet and our species then I know of no finer summary of present knowledge.

Dave Bishop, April 2011

No comments: