Agriculture is an evolutionary phenomenon. The popular myth is that agriculture began when humans realised that planting seeds in the ground would make them grow. The truth is that agriculture is a mutualism that evolved (in the biological and not merely colloquial sense of the word) from a novel ecological interaction between plants and humans. At the very origin of this mutualism, cereals rapidly adapted to the novel environment (Allen, 1977). Harvesting favoured the evolution of synchronous seed ripening. The cycle of harvesting, storage and sowing created a strong disadvantage to seed dispersal, which would remove a plant's progeny from the advantageous mutualism. Thus, newly domesticated grains rapidly evolved seed heads with a non-shattering rachis. Sowing favoured the adaptive loss of seed dormancy. These evolutionary changes were effected by people who would have been largely unaware of the selection they were imposing (Allen, 1977).

Today, evolution may seem a remote concern for agriculture, yet an evolutionary understanding of plant reproduction may provide new directions for crop improvement and agricultural management. In this chapter, we consider what evolutionary biology can tell us about crop pollination and yield. Evolutionary biologists interested in pollination have tended to ignore agricultural settings, but well-studied topics such as pollen limitation of seed set and morphological adaptations of flowers for pollination apply equally to wild and domesticated species. More recent concerns, such as the network structure of plant–pollinator interactions in different habitats, may also help us understand how invasive agricultural species interact with established pollination webs.

Applications of ecological principles to agriculture are usually developed within the discipline of agroecology, a term first used by the Russian agronomist Basil M. Bensin in the late 1920s (Wezel et al., 2009). Traditionally, however, agroecological research has focused on ecology, socioeconomics and sustainability of productivity. It is only recently that more explicit evolutionary approaches have been applied in this discipline, so much so that even articles published as recently as 2003, devoted to the issue of scaling – including time scaling – in agroecology, do not explicitly address evolutionary dynamics and processes (e.g. Dalgaard et al., 2003). Nevertheless, such a situation is being redressed in more recent work, where a new emphasis on evolutionary agroecology is steadily surfacing (Thrall et al., 2010; Weiner et al., 2010). However, the role of evolution in agriculture has been central since the very beginning of this practice: agriculture itself is, indeed, a long coevolutionary process (e.g. Hart, 1999). In this chapter, we aim to briefly review some major applications of evolutionary principles to agriculture and in the ‘Looking forward’ section we will endeavour to suggest some future directions in evolutionary agroecology. Agriculture has been called ‘the greatest ecological experiment on Earth’ and has also been described as always being in a state of ‘tension’. We are now beginning to realise more fully how the ‘experiment’ and the ‘tension’ implicate evolutionary processes as well as ecological ones.

The main issues

The fundamental premise behind almost all agricultural systems worldwide is that ecological succession is halted. In arable and vegetable cropping, for instance, annual plants can dominate the landscape. Virtually all interspecific competition is reduced to a minimum; this includes weed management within and around the crop and sometimes the reduction or removal of largely woody field margin plants. Similarly, farming attempts to reduce any negative impacts of evolutionary processes on the farming activity. These may include the development of insecticide resistance in insect pests, fungicide resistance in fungal plant diseases and weed resistance to herbicides. As well as attempting to reduce the impacts of evolutionary processes, farming also largely ignores the benefits which can accrue from a more complete understanding of the role that a knowledge of evolution can play in helping to make agriculture more ‘sustainable’. Examples of some of the evolutionary processes which are either ignored or restricted in some way are given below.

One of the most influential concepts in artificial intelligence is the notion of the swarm. That is, intelligent adaptive behaviour can arise in large groups of interacting agents, even when the individual agents have limited local information and use simple rules. Self-organisation provides a basic structure in such agent societies, while natural selection can drive the evolution of increasingly efficient and coordinated interactions through improved communication, information processing and agent specialisation. Such collective intelligences have evolved in diverse biological contexts, ranging from foraging and home-building colonies of ants, termites and bees, to the coordinated movements of vertebrate flocks and schools, to the exquisitely tuned dynamical responses of immune and neural systems. Here, we discuss how these biological models contribute to emerging technologies in fields such as optimisation, robotics, image processing, self-repairing systems and automatic structure design.

The main issues

Many modern engineering designs have been based on natural adaptations, a procedure termed biomimicry (Benyus, 2002). Among the more ambitious of these designs are those that incorporate the selective process itself. By evolving solutions to problems, researchers aim to capture the robust and adaptive properties of organisms. The growing complexity of information technology demands machines and algorithms with the ability to respond flexibly and intelligently to new situations without supervision, a feature common in living systems but virtually unheard of in normal engineering. David Green describes in Chapter 12 how natural selection can be used to solve difficult problems via evolutionary algorithms. Here, we will consider how evolutionary theory can contribute to technology more broadly through swarm intelligence (Beni, 2005; Bonabeau and Theraulaz, 2008; Camazine et al., 2003; Krause and Ruxton, 2002).

This chapter will consider whether neurodegenerative diseases may be informative with respect to the scaling up of the central nervous system (CNS) over evolutionary time. Neurodegenerative illnesses are becoming increasingly prominent as the world's population ages demographically. Alzheimer's disease (AD) represents the most common form of dementia, a major neurodegenerative illness. AD brain pathology progresses in a well-characterised dynamic sequence: there is an advancing wave of cortical atrophy sweeping from limbic and temporal cortices into association areas of the cortex which subserve higher order aspects of cognition, including declarative memory (Braak and Braak, 1995). In contrast, neuropathological changes are minimal in brain regions which mediate more fundamental cognitive processes underlying perception and movement. Taken together, are these changes informative with respect to how the brain evolved? Specifically, does the sequence of neuropathology and cognitive symptomatology in AD represent a type of ‘reverse ontogeny’ in humans? Additionally, in the context of pragmatic evolutionary considerations, could a better evolutionary understanding of the brain help in improved diagnosis and/or treatment for neurodegenerative illnesses such as AD?

The main issues

We start by considering whether neurodegenerative illness may be informative with respect to the evolution of the CNS. In order to provide some context, we initially reflect upon some of the ‘fundamentals’ of brain evolution.

The world is currently experiencing loss of biodiversity due to direct and indirect anthropogenic causes unparalleled in human history. In this chapter, we expound on the importance of evolutionary thinking in our efforts to mitigate this loss. In Otto Frankel's (1974) words, ‘reinforcing the grounds for nature conservation with an evolutionary perspective may help to give conservation a permanence which a utilitarian, and even an ecological grounding, fails to provide in men's minds'. A simple argument-from-definition could be presented to justify this presumption: evolution is defined as change in the frequencies of genes and gene variants over space and time; population genetics deals with the intraspecific component of this dynamic; conservation genetics is applied population genetics, hence the direct link between evolution and conservation genetics. We aim to put forth a more synthetic justification based on the analysis of empirical studies that link evolutionary processes with conservation objectives.

Historical prelude

A number of recent reviews (Avise, 2010; Frankham, 2010) and books (Allendorf and Luikart, 2007; Avise, 2008) have documented historical developments in conservation biology that led to the emergence of the relatively young subdiscipline of conservation genetics. Awareness of the importance of conserving heritable variation dates back to Charles Darwin's days (Darwin, 1876). The 1960s and 1970s heralded molecular techniques that enabled quantifying heritable variation in natural populations (Hillis et al., 1996). In 1970 and 1974, building on these technological developments, but more significantly concerned over the vanishing genetic diversity of crop plants as a result of monoculture and the introduction of input-needy high-yielding crops in areas of genetic diversity, Otto Frankel published seminal papers on the urgent need to conserve genetic diversity. This led to changes in awareness not only among the scientific community, but also among the general public, particularly among conservation oriented non-governmental organisations (NGOs) and other civic groups (Mooney, 1996). A meeting of ecologists and evolutionary geneticists was held in 1978 aimed at integrating their respective approaches to mitigating the problem of extinction (Allendorf and Luikart, 2007) and acknowledging that conserving genetic diversity plays a significant role in this. The subsequent publication of Frankel and Soulé's book Conservation and Evolution in 1981 and the launch of the journal Conservation Genetics in 2000 represent significant milestones. The first dedicated conservation genetics textbook by Frankham was published in 2002 (Frankham et al., 2002).

What is knowledge good for?

In ancient Greece, ‘philosophy’ meant love (philia) of knowledge (sophia). Had Epicurus spoken the language of modern science he would have said something to the effect that there is no use in our only scientific theory of life unless it is good for something. Indeed, he might have gone on to explain that the ultimate function of our evolved capability for knowledge is therapy; goodness for us, so to speak. Knowledge is information about our material and social environments represented in our bodies. It helps us develop health and well-being and cast out disease and dysfunction, in ourselves and our loved ones. Aristotle and Confucius both used the metaphor of an archer to make the same point: just as it's hard for an archer to hit his mark without a clear view of the target, so too is it hard for our plans to succeed without a clear view of what they are for. Aristotle believed that ‘human flourishing’ should be the target of ethics and governments. As Jennifer Prah Ruger put it in Health and Social Justice, Aristotle believed that human ‘flourishing’ (eudaimonia) should be ‘the end of all political activity’ (2010, p. 45). Ruger's book is an exploration of what a health policy informed by Aristotelian ethics might look like. In his foreword to the book, Nobel Laureate Amartya Sen describes her project as one of shifting the target of public health from ‘good health policy’ to ‘policy good for health’ (p. ix). Ruger accomplishes this shift by emphasising the moral imperative of health. Health is special, she argues, just because it is constitutive of the ultimate aim of politics, human flourishing.

This is all well and good, but as a scientist I have to ask the begged question: why should we care about human flourishing or its constituents, including health? Why should it be the end of all political activity? My own target in what follows is to show how an evolutionary perspective on healthy feelings might contribute to ‘policy good for health’.

An evolutionary perspective reveals why immune processes are intricately interconnected with each other and with other biological processes within multicellular organisms. This web-like interconnectedness has important implications for medical interventions. Evolutionary considerations suggest that direct manipulation of molecules and processes within the immune system are inevitably going to be associated with detrimental side-effects that result from the web-like interconnectedness. Manipulations of the immune system's exposure to threats, however, has led to many of the most successful achievements of medical science, because this sort of manipulation takes advantage of the inherent strengths of an intact immune system, by giving the immune system the upper hand in its attempts to control these threats. Evolutionary considerations also offer a new way to complement the intact operation of immune systems – by designing health interventions, such as vaccination strategies, to control the evolution of pathogen virulence.

Evolution of immune systems

One of the problems the first multicellular organisms encountered was the need for protection against unicellular organisms (e.g. bacteria) or subcellular agents (e.g. viruses). Although the mechanisms of this parasitism were probably similar to those involved in parasitism of unicellular hosts, multicellular organisation posed some additional vulnerabilities. Multicellular organisms required time to develop from a single cell and evolved cellular specialisation for different tasks. The longer time associated with multicellular development created a vulnerability, because any parasite that could circumvent the defences of a single cell could have immediate potential access to the host's other genetically identical cells. To restructure the genetic basis for its defences, the multicellular host would have to await development to maturity when sexual reproduction could create genetically different cells (Hamilton, 1980). A host's cells might still be able to rely on the defences that unicellular hosts have against parasites, such as destruction within phagosomes, but competition between multicellular organisms favours specialisation of cells for different purposes, such as neuronal conduction, support, sensing stimuli, proliferation and reproduction. Maintaining the entire suite of defensive armaments within each cell would compromise the ability of cells to be superior at their specialised functions.

Homosexuality or same-sex sexual orientation has a very long history in the medical field as pathology of sexuality, starting from the nineteenth century (Bullough, 1974; Adams and Sturgis, 1977; Coleman, 1982; Beckstead 2001; Conrad and Angell, 2004). Officially, however, homosexuality was removed from the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-III) in 1973. This change notwithstanding, the current version of the DSM (DSM-IV-TR), in place since the year 2000, still includes the categories of Gender Identity Disorder (GID) and Sexual Disorder Not Otherwise Specified and its subcategory, Persistent and Marked Distress about Sexual Orientation (Throckmorton, 1998; McCommon, 2009), that leave a door open for the persistence of psychotherapeutic practices that aim at either changing the sexual orientation of homosexuals to heterosexuality, or to maintain the homosexual orientation but eliminate homosexual behaviours. These practices are variably known as conversion therapies, reparative therapies (e.g. Grace, 2008), or re-orientation therapies (Masters and Johnson, 1979).

In this chapter I start with the main issues section, where I briefly review the historical background of ‘homosexuality as pathology’, the emergence of conversion therapies, especially those that have a religious motivation; the criticisms that such therapies have received, including the establishment of alternative gay/lesbian affirmative therapies, and the current approaches that aim at integrating the various dimensions that are relevant to the life of homosexuals. In the ‘Looking forward’ section, I propose an evolutionary view of homosexuality as an adaptive expression of sexuality, not as pathology, and endeavour to establish some evolutionarily inspired criteria that may help both therapists and counsellors in their approaches to homosexual clients, especially in cases where those clients feel the necessity to seek consistency between their sexuality and their strongly held religious beliefs.

Teenage pregnancy is associated with poor maternal and child health outcomes that can resonate throughout individuals' lives and into future generations. Across many industrialised nations, teenage pregnancy rates remain high despite extensive efforts to introduce government policy and public health interventions aimed at reducing rates of young motherhood. Indeed, more than 1.25 million teenagers become pregnant in OECD nations each year (UNICEF, 2001). In this chapter, we use a branch of evolutionary theory (life-history theory) that studies life cycles within an environmental context to better understand what are likely to be the persistent underlying antecedents of teenage pregnancy.

The main issues

Policy efforts to reduce the rates of teenage pregnancy have had little impact (e.g. Johns et al., 2011); this chapter aims to use evolutionary theory as a practical guide to identify antecedents of early reproduction. Life-history theory is devoted to the study of survival, growth and development and reproduction (i.e. life cycles) in an ecological context. It focuses on the timing and duration of major events such as age at first reproduction, number and size of offspring, interbirth intervals, length of parental investment (e.g. age at weaning), and lifespan. These life-history traits often covary in what is referred to as a reproductive strategy. This theoretical framework has been applied successfully to the study of non-human animals' life cycles (see Stearns, 1992) and the timing and duration of life histories, including reproductive timing, in traditional human populations (e.g. Hill and Hurtado, 1996).

Preface

When scientists refer to Evolution they often do so by also adding the word ‘theory’. This may give the impression that the Theory of Evolution is ‘just a theory’. Obviously, it is not. It is, in fact, the best scientifically corroborated view of life that we currently have; there is no other credible alternative that succeeds equally well at explaining the known facts of life after the strict criteria of the scientific method are used to sieve through the available contenders. Aerodynamics is also a theory – applied to aircraft design – but, consciously or unconsciously, we do not regard it as ‘just a theory’ each time we board an aeroplane. As with mathematics, theoretical physics and chemistry, if evolutionary science provides a sound description of reality, then such knowledge could be applied for the benefit of all. In this book, a team of leading specialists in various disciplines ranging from palaeontology, genetics, ecology, agriculture, fisheries, medicine, neurobiology, psychology and animal behaviour to information technology, education, anthropology and philosophy come together to explore the many and very diverse applications of evolutionary thinking. The result is a smorgasbord of examples and very many ideas that I hope will excite the imagination of the reader. Evolutionary approaches may be especially useful whenever we want to find solutions to problems that are associated with complex systems, solutions that take advantage of the evolved capabilities of organisms. Such an approach may succeed where more reductionistic strategies have failed. On the other hand, some multi-organismal entities (such as populations, communities, ecosystems) and also individual organisms may contain modular aspects that could facilitate more reductionistic approaches to problem-solving in specific cases. For instance, highly specialised molecules could be manipulated in order to solve a specific problem without great fear of unexpected side-effects. A very different approach is required for molecules that have many effects across different aspects of the physiology of the organism. A better understanding of the evolved reality of the system that is the focus of our attention will help us harness such a reality to produce the outcomes that we want to achieve, whilst minimising time spent, costs, side-effects and maximising sustainability of the solution. These basic principles are specifically illustrated in the various chapters. I invite the readers to use this book not only as a source of information to better understand contemporary evolutionary science and its applications, but, above all, as a source of inspiration to explore new possibilities for constructive evolutionary applications across many fields.

Really, when you think about it, my title asks a bit of a daft question. Your daughter comes home and says she is going to become a Jehovah's Witness. Do you reach for The Origin of Species for guidance? Some nasty anonymous academic wrote a critical letter and so you fail to get tenure. Descent of Man, anyone? Sarah Palin gets elected President of the USA. How about a quick dip into the Voyage of the Beagle? Obviously when you put things that way, Darwinism is about the last thing you would turn to for existential reassurance (whatever that might be) at times of personal or social crisis.

On being human

So let us go at the question in another way. What would you turn to for reassurance at times of crisis? I take it that by adding the qualifier ‘existential’ we are ruling out the bottle, comforting though that may be. Although I don't think we should be too prissy or professorial about this sort of thing. If someone says that when things go wrong they go for a massage and a manicure, that seems to me a pretty good idea. It may not solve things as such, but it may well help you to relax and be better able to deal with a crisis. I remember many years ago when I was an undergraduate and very unhappy in the course of studies I had chosen, I found that listening to Mozart was a terrific way to stay on keel.

Since Charles Darwin published his seminal work On the Origin of Species by Means of Natural Selection (Darwin, 1859), museums around the globe have been greatly expanding their holdings of palaeontological collections, and it is estimated that they now hold several hundred million specimens (McNamara and Long, 2007). Most scholars today acknowledge that the little information gained from the few fossils known in Darwin's day was almost superfluous in formulating his theory of evolution; it was largely icing on the cake to reinforce the work achieved by his lifetime studying both biology and geology (Bowler, 2009).

Today, these vast collections of fossils continue to provide valuable data towards resolving many of the crucial stages in the transformational macroevolution of the major vertebrate groups, as well as greatly elucidating both the nature and tempo of evolutionary trends (McNamara, 1997; Gould, 2002). Fossils have also provided valuable reference points for testing the reliability of molecular divergence times for defining the timing of critical branching events in phylogenies (Kumar and Hedges, 1998; Hurley et al., 2009), as well as providing nodes in time for the hypothetical origins of certain kinds of physiological traits such as air-breathing (Long, 1993; Clement and Long, 2010), or reproductive behaviours such as copulation (Long et al., 2008, 2009).