- Publisher: Earthscan
- First published: 2007
- ISBN: 978-1-84407-432-7
One hundred and twenty years after Charles Darwin turned the world upside down, along with Alfred Russel Wallace, James Lovelock wondered too with his Gaia hypothesis if the earth had been shaped by life. Such Kuhnian paradigm-shifts cause rapid differences to emerge. The new believers wonder why they did not think of it first; the old disbelievers think it all utter nonsense, and sit back and wait. Years can pass before the new comes to be accepted. Max Planck famously once said, “a new paradigm is often accepted not because it convinces the majority of its opponents, but because it outlives them”. Gaia remains controversial, mainly because some have misrepresented it as suggesting the Earth itself is alive. This was never the intention, but it remains an appealing idea to some searching for a guiding hand. What Lovelock did say was that life helped to make the earth a place where life could persist. It made its own bed, and it’s a comfortable one. At an average current temperature of 13o C (until climate changes fully takes hold), the earth is hospitable. Mars and Venus, by contrast, are thoroughly inhospitable, one bitterly cold and the other twice as hot as an average oven. Life maintains the earth’s biogeochemical cycles far from equilibrium, and this in turn helps to shape and influence the kinds of life that persist.
This makes the biosphere an emergent property of millions of years of interaction between life, the earth and its environments. We humans are part of this process too. Hominids emerged some five million years ago (our genus about 2.5 million years ago; our species about 160,000 years ago), and we have been shaped by hundreds of thousands of generations to arrive at where we are today, bicycles notwithstanding. To paraphrase Sartre, all our lives have led us to this very moment. And here is the link back to Darwin, whose shattering idea of evolution driven by natural selection recognised the mechanism by which the many forms of life have emerged, survived, and diverged in their specific environments. It is now clear that individual organisms, populations and their species change their environments, often in ways that increase their chances of survival. Survival of the fittest also means survival of those that influence their environments in a favourable way, and can then pass on these capabilities to descendents.
At the same time as Darwin’s Origin of Species was published, a monk in Austria was laying the foundations for modern genetics. Gregor Mendel’s experiments with peas during the 1850s and 1860s clearly showed how characteristics, or traits, could be passed from one generation to another (though his work was not recognised until the early 20th century). A half century after this, Francis Crick, James Watson and the mostly forgotten Maurice Wilkins and Rosalind Franklin established the structure for DNA, which later allowed chromosome structure and gene expression to be determined. Another half century of huge collaborative efforts across laboratories in many countries have seen all the genes for a number of organisms be fully mapped, including the 30,000 or so genes of humans. For a while, this appeared to suggest we are near to knowing everything about us and these other mapped organisms. But this is far from true. We know more, but also have gained insights into how little we still know.
Mapping and naming genes is like picking up the phone directory for your local town or city. Lots of names and numbers, structured in columns, and helpfully all in alphabetical order. But from these lists alone, you can only guess about the structure and functioning of the city. You need to ring up every person (or gene) and ask them what they do. You then need to find out what causes that person to get up in the morning. What are their motivations? If it is a rainy day, will that person stay inside; if sunny, go to the beach? Will that person do something when another person (gene) in the phone book calls them and invites then over for tea, or was it to the pub? You may have a contact that calls every day; and another one only every five years. Now we have a pretty good gene phone book, and have begun to realise that we understand so little about how they interact – both with other genes and with the environments that are internal and external to the organisms which carry them.
This, then, brings us to another enduring controversy. How much do genes or the environment affect who we are? Is it nature (genes) or nurture (environment or culture) that is mostly, or even solely, important? Like all these handy dichotomies, the truth lies in elements of both, not one or the other. But the post-Darwin literature is often less forgiving. And this has led us into many difficult places. A century of polarised opinions seemed to explode in the mid-1970s with the publication of E O Wilson’s Sociobiology, in which biological explanations were provided for many aspects of human behaviour and society. Many social scientists attacked Wilson, as did some evolutionary biologists. Part of the problem may have come from Wilson’s provocative claim that the social sciences would eventually be subsumed into biology, as he indicated that a great deal of behaviour could be explained by biology alone. Even after the dust from this particular controversy has settled, there still remains a wide range of divergent views, from those who appear to reject any cultural explanation of human behaviour, to those memeticists who seek to provide evolutionary perspectives that are essentially cultural. What is not clear is that evolution does not have a directing hand, or a determined pathway. It is about adaptation to environments, changing environments to make them more suitable, and then survival of those genes (and the organisms that carry them) that are best able to do these things.
As we shall see, genes play a fundamental role in shaping who and what we are, but they do not act in a vacuum. They take their signals from the environment, which once was predominantly ecological but now is cultural too, and these signals switch on and off genes. What we are is actually an emergent property of both genes and ecological-social environments, and thus we do have choice. We cannot bend our genes to our intentionality, at least not personally, but we can and do affect the environment which indirectly presses our genetic buttons. Thus, as Kevin Laland and Gillian Brown say, “using evolutionary theory is not the same as taking a genetic determinist viewpoint”. Indeed, says Richard Dawkins, “the bogey of genetic determinism needs to be laid to rest”.
The controversy over how much genes or the environment affect who we are is curious, as we pretty well accept the fact that genes are units of inheritance. Genes determine a great deal, but strangely we do not seem to find this a comfort. The problem centres on questions of free will, which we would all like to think we have. I am free to choose what I think or like, I am free to be happy or sad, or to choose one person or food over another. I can choose, in other words, my own future. It is not, though, that simple. Genes shape those choices, as we do our environments, which once had antelopes in them, but now have supermarkets and fast food outlets. And how much free will do we actually have when it comes to buying food? Are we not subliminally influenced by advertising anyway? Do the stores seek to influence your choices in subtle ways? Of course they do. The average American child will have seen 360,000 TV advertisements and 200,000 violent acts by the age of 18.
Both genetic determinism and the idea of being born with a blank slate are wrong. None of the commonly used binary oppositions are alone correct – genes or environment; nature or nurture; innate or acquired; individuals or culture. The problem is that false insights into these questions has led to the expression of many political and social prejudices, and in the hands of tyrannical leaders allowed many atrocities to be justified. Some believed they could and should create a master race (as if the environment did not matter), and others believed that could rewrite human nature if social circumstances were changed (as if genes did not matter) (though most do not occupy such extreme territory). The worries about genetic determinism, though, are centred on false ideas about genetics. As Matt Ridley has rightly put it, genes are not gods. Just because you or I have a particular gene does not mean it will necessarily be expressed (it may sit quietly doing nothing), and equally, if we lack a certain gene, it does not mean we will lack a trait or characteristic (another gene may step in, and do the job instead).
The central dogma of genetics has long been that information flows out of the gene, and not back to it. Experience (the environment) does not change gene sequences (DNA), otherwise Lamarck was correct. But information does flow back to genes to affect their expression. Genes are switched on and off by signals from the environment. These signals can be transcription factors (which are themselves encoded by genes) that bind to the promoter sequences of genes, or a range of other molecules, such as proteins, that transmit external environmental cues into some form of internal signal. Each of us carries our own phonebook set of genes, but not all of them are expressed in a lifetime. It depends on the external and internal signals that switch genes on and off.
Daniel Dennett has called the concern about genes and free will, “the panic that lies underneath the surface”. Are we fully responsible for our actions? We may more often come to hear the cry: `it is not my fault, it’s the fault of my genes’. Indeed, this has already happened in the US, where in 1994 the lawyers for a convicted murderer, Stephen Mobley, argued in his appeal that he came from a long line of criminals, and that he committed murder because his genes made him do it. In short, he wanted to pretend he had no free will. This raises more fundamental philosophical questions. People generally want to be responsible, want to have the choices to avoid a behaviour that may be coded for by a particular set of genes. Yet knowing about how genes and the environment interact could actually increase free will, not constrain it further, as some people worry. When we know that certain genes are associated with certain kinds of behaviour, it does not mean that someone with that gene is locked into a certain and inevitable pathway. They still have choices. We rewrite ourselves as we grow.
Organisms do not evolve in a static environment. They are constantly changing it, and therefore changing the course of their own evolution. As David Krakauer of Santa Fe Institute says, organisms are “builders engaged actively in the planet’s construction”. This is what Kevin Laland and John Odling-Smee have called niche construction. Organisms modify the environment and so modify the sources of natural selection too (often to make them more favourable). All organisms constantly interact with their local environment, and so change them over time. Earthworms change the structure and chemical composition of soils by dragging leaves and other organic matter into the soil, and thus mixing organic with inorganic materials. Thus, “contemporary earthworms live in worlds that have been partly niche-constructed by many generations of ancestors”. Other niche modification examples include elephants that uproot whole trees, open canopies, create parkland, and recycle the herbage through their bodies that in turn reduces the incidence of fires. Hippos create close-cropped riverside grasslands, and as large browsers trample vegetation and keep the understorey open. Wild boar create open ground and aid tree germination, and beavers form riverside water meadows and coppice willows. Thousands of spectacled eider duck assemble on the Arctic Sea during winter to keep the sea ice open through their continuous movement on the surface, so allowing them to dive down 60 metres to get food throughout the winter.
The idea of niche construction is similar to Dawkins’ idea of the extended phenotype. Genes build environmental states beyond the organism to increase their chance of survival. Some extended phenotypes can be inherited, if the environment is changed, and benefit future generations, which then continue to maintain the environment in a favourable state. Ecological inheritance does not depend on just biological replicators (genes) but the persistence of physical changes too. Organisms modify environmental resources. They effectively try to change their worlds to make them more favourable to their own survival. Laland and Odling-Smee suggest that organisms shape environments as surely as environments shape organisms, with the result that “evolution is transformed from a linear to a cyclic process”.
But Odling-Smee and Laland also suggest another concept – that of negative niche construction, when organisms destroy their habitats. Could we humans be driving ourselves to extinction by harming the very environments in which we evolved so successfully? It is now an increasingly common conception that humans are well-adapted to the ancestral Pleistocene environment, and not particularly to the industrialised environment. But this is only partly correct. Foundations were indeed laid, but evolution has been working since then. We have also been modifying the later environments, and these must have been having an effect on us too. Niche construction also suggests that the initial environment of savannahs was in the first place shaped by hominids. We did not simply evolve in one environment, and then stop. We continued to change.
For most of our time, therefore, we have survived in a world rich in biological diversity. We have, of course, been part of this diversity, shaping it and being shaped in return. We change the environment – burn the grasses to prevent scrub encroachment, channel the water to trees, collect the fish with care – and it shapes us. The natural environment is not a fixed entity that does not change over time. We amend it, and it affects which of us will survive. But if the shaping is harmful, does this mean we eventually harm ourselves? Are humans now, by causing massive species extinctions and changing the global climate, actually threatening the survival of modern civiliation? It would be good to know now, as it might still be possible to do something about it. Ancestral humans did clearly play a significant role in reducing biological diversity before this generation’s extraordinary extinctions. We hunted the mammoths to extinction in former Europe, the ground sloths in the Americas, and the slow moving ground marsupials in Australia. But nothing compares with today’s losses – called by many the sixth great extinction. The previous five were all caused by global geological or climatic catastrophes. This one is being provoked by humans alone.
As knowledge of gene function increases, so many new questions are raised about environmental influences. It is now known that weight is partially heritable: the correlation in weight amongst identical twins is 80%, but is only 43% amongst fraternal twins. Thus given the same access to food, some people will put on more weight than others. Food shortages during pregnancy change the likelihood of the embryo suffering from obesity in later life. A poorly nourished baby is born expecting to live in a state of food deprivation throughout its life. Its metabolism is geared to being small, and is good at hoarding calories and avoiding excessive exercise. If this individual finds itself with plenty of food all the time, then it responds by growing rapidly, putting on weight and straining its heart. If there is famine in the first two trimesters, then babies with normal birth weight themselves give birth to small babies. On the savannah and other locations where food is sometimes scarce, they survive. In the cities populated with junk food outlets, they will not.
Ever since the earliest hominids stepped into the savannahs, some 250-350,000 generations ago, a dance of genetics and culture has determined which genes have survived to reach us today. In some circumstances, the fittest have survived – those that caused their bodies to run the furthest when the prey needed chasing down. In others, the richest or most powerful survived – those with the resources to ensure their progeny survived best. It is the poorest who are more likely to suffer high levels of infant mortality; it is the richest who are more likely to pay their way out of a problem – buying clean water rather than relying on sewage-contaminated ponds. The balance between biology and culture changes through human history, but will it change again? What will the future bring? There are two certainties. Environmental destruction will continue for some time, perhaps the whole of this century. At the same time, medical and biological technology will transform us internally, perhaps even bringing mergers with silicon technology to produce new cyborgs. We may bring on an age of destruction, and an age of isolation at the same time.
Natural selection produces diversity, but only because a variety of environments or conditions means that a range of genes are required. If the environment becomes a monoculture, then inevitably a more limited set of genes will be selected. Monocultures are not just bad because they are not diverse. They undermine the fundamental nature of the biological world itself. Today’s industrialised processes have often come to mean a desire for homogenisation. Yet a diversity of environments, or opportunities, drives evolution, so not only are we destroying species through habitat destruction, we are undermining the likelihood of persistence of the world as we know it. Evolution increases information content and increases intelligence. Will ecolution continue these processes after our current age of destruction – of biodiversity, of nature, of languages and communities, of stories? Good communities are places where imagination grows and memories persist. Does imagination, like intelligence, grow over time? And has it now stopped growing in the modern age? Has, in other words, normal evolution been put on hold (whilst we destroy and are destroyed)?
The key to ecolution is imagination and interest. The modern homogenised world has reduced our understanding of the natural world, our daily connections, our capacities and desires to care. We develop other interests – and there is nothing inherently wrong in these, whether electronic games or films, or celebrity goings-on. The problem only emerges if we come to think of these as a replacement for the real world, and that there is no other reality that matters anymore. Diversity of places (and their associated memories) is good as it provokes imagination and desire, and provides stability at the same time. It makes us think about how to solve new problems, to understand things. After all, we all have genes passed on from a group of hominids that left the savannahs of Africa and dispersed across the world – discovering new environments, learning sufficiently rapidly to prevent consumption by larger predators, and changing the world to suit us.
Evidence suggests that we have some innate connections to nature, and also to diverse environments. When, then, do we lose heart and interest? When we no longer feel we can influence the future. When we have a repetitive and boring job, or when the commute to work is the same, day after day. We then yearn for something else, something new, an escape. Why do we go to different places for our holidays and in our leisure time? Why do we wish to visit the big city when we grow up in the country? Why do we wish to follow our relatives to another country? Of course, finance and opportunity play a role. That cities have streets paved with gold is an enduring component of many myths and stories. When we do not move, then we do something else to keep up the interest and provoke imagination – we tell stories and create myths. We make the world more interesting by telling stories that may carry important messages, but most importantly they seem to make our lives have more meaning. They are fuel for our minds. Without it, we are diminished, and our mental well-being suffers. We need mysteries and questions, as memories link the present to the past, compressing time into space. But a monoscape has no mysteries and no memories.
A phase of ecolution is now required, in which the value of cultural diversity is reaffirmed, and the value of biological diversity is recognised and increased. But will this lead to the survival of the greenest – or simply once again the richest (or even the most environmentally-destructive)? A preserved, green world has more opportunities for emotional well-being of the people in it – and different people like different environments, from the tundra to tropical rainforests, from the savannahs to the sands (and theatres, cafes and concert halls). If we lose these environments, then we lose the opportunity to express some of our genes, and these will decrease in frequency over time. And we will change. An environmentally-impoverished world will be a post-human world. Poet Gary Snyder says, “how could we be were it not for this planet that provided our very shape? The land gave us a stride, and the lake a dive… We should be thankful for that”.
Ecolution, then, suggests the need to recognise the tightly coupled nature of ecological and social systems, and to develop new opportunities for creative self-organisation for enduring with this world. Our condition is linked to that of the planet. Now they are both in crisis, on a collision course, with potential for destruction of biodiversity, cultures and life as we know it on the planet itself. In an imagined post-industrial world, human populations will fall, perhaps to as low as half of our current numbers. Many pressures will have been lifted. But can we make it across this century, possibly the most critical of all human history?
Put simply, we collectively have the choice. Our genes are saying nothing. T S Eliot says, “humankind cannot bear very much reality”. Our genes are at the mercy of the environment. What kind of natural and social environments will we now create – ones that are harmful to us and our genes, or ones in which we can coevolve and survive?