Life on Earth began with thermophiliac organisms powered by heat from the Earth's core. Later, surface life evolved. It was powered by the energy from the sun, and then in layers of prey and predators. This page is a description of the energy transfer system known as the food chain and a look at some more esoteric issues surrounding the nature of this system, including discussions of genetically modified food.
Life started deep in the crust of the Earth, where the oxidation of sulphur was powered by the intense heat from below. These ancient thermophiles eventually multiplied, diversified and evolved to cope with colder and colder climates. When a chance mutation resulted in the production of light-sensitive chemicals, life eventually emerged on the surface and floated in the cooling oceans.1. Micro-organisms are still the most diverse and successful forms of life on the planet.
A spoonful of good quality soil may contain ten trillion bacteria representing 10 000 thousand different species! In total, the mass of micro-organisms on Earth could be as great as a hundred trillion tonnes - more than all the visible life put together.”
Forgetting the ancient thermophiles, the Sun is the engine that has since kept surface life on Earth sustainable. Photosynthesis converts radiation from the sun into chemically stored energy, creating organic molecules in the process, and expiring oxygen into the atmosphere. The rate of plant growth is called 'production'. Production is measured in grams per meter squared per year. For example, shallow waters produce 2500g/m2/yr. By dividing living creatures into layers, we can examine how energy from the sun makes its way up the food chain in the form of biological chemicals. These 'layers' are called trophic levels:
“The fate of energy can be followed through a consideration of a simple energy transfer model, called a food chain. Each stage in the chain is called a trophic level. Plants are the first level in the chain and are called producers. [...] Herbivorous animals are the second trophic level and are called primary consumers. They in turn are eaten by the third trophic level. [...] At each trophic level a conversion to heat takes place, which means that less energy becomes biomass at the succeeding trophic level. [...] This explains why most food chains are limited to four or five trophic levels, and why the animals at the end of the food chain, for example lions, have to roam over large areas to obtain their food, because one small area cannot support many of them.”
"The Nature of the Environment" by Prof. Andrew Goudie (1993)2
Depending on how you count, bacteria makes up nearly 50% of the biomass of the whole Earth3. That's right - nearly half of all life is bacterial (and over half is microscopic1). This provides a massive first-layer, primary food source for slightly complex multicellular life forms. Consumption, like all mechanical engines and chemical pathways, is not 100% efficient. Far from it. At all stages, energy is lost to inefficiency, wasteful digestive systems, and heat production. Prof. Dawkins, the foremost evolutionary biologist, informs us that only ten percent of the energy from one trophic level makes it to the next level up4.
This implies that at most trophic levels, the total biomass must decrease, the feeding/hunting area must be bigger, and the digestive systems have probably evolved to be more complicated in order to digest more complicated fats and sugars. It turns out to be true. Bacteria feed over a very small area, plants and primary producers feed over a wider area but in total, less biomass is held in plants than in bacteria (that make up 50%), and eventually, the predatory animals hunt over wide areas, and are massively fewer in number than their prey.
Dr Richard Wrangham of Harvard University notes that cooking is a behaviour found universally in human societies. Only very few single individuals attempt to live without it. Some have theorized that this radical behaviour formed a major factor in our rise to stardom. Dr Wrangham investigated the effect it has on food, and finds that it hugely improves the efficiency of the energy gain from the food cycle. Commentary was published in The Economist:
“Cooking alters food in three important ways. It breaks starch molecules into more digestible fragments. It "denatures" protein molecules, so that their amino-acid chains unfold and digestive enzymes can attack them more easily. And heat physically softens food. That makes it easier to digest, so even though the stuff is no more calorific, the body uses fewer calories dealing with it. [...] Cooking increases the share of good digested in the stomach and small intestine [...] from 50% to 95%.”
The Economist (2009)5
The improved food-consumption efficiency that is gained through cooking, and the learning curve of dealing with fire, and tools, are three things that set humankind on a radical new evolutionary path.
Energy Efficiency (assuming alien life is a little similar to ours): Life on alien planets could also be dividable into trophic levels; that the greatest abundance of biological chemicals is contained within unicellular lifeforms is great pressure for hungry multicellular species to evolve in a direction that involves digesting single-cell lifeforms. The result is a trophic system. It is also likely that on other planets, as on Earth, the evolution of digestion isn't optimal. The jury-rigged nature of evolution does not mean that the most-efficient routes are always evolved. What works, may survive. In short, there is a maximum limit to the amount of trophic levels you can have. Humans, who shop for food over massive distances (the whole planet), exist at the top level alongside other big omnivores. The footprint of the top hunters is huge, and by and large it is too inefficient for hunters on the top layer to spend time hunting each other. If plankton only process 10% of the sun's energy efficiently, and millions are eaten by fish at only 10% efficiency, etc, it is more efficient for predator fish to eat the next layer down in order to 'collect' the same quantity of plankton-food-mass. To eat each other would result in no net gain of energy into that trophic layer; so, much energy must be obtained from the layers below. At each layer, the storing of fats and sugars gets more complicated. The more complicated the biological chemicals, the harder it is to digest them. That's why bacteria doesn't eat chocolate, but we can. At the top trophic layer, our digestive systems can break-down chocolate into the smaller chemicals prevalent in lower trophic layers, and digest it. We then reassemble it into complex proteins, etc. If aliens visited Earth, they would be unlikely to eat us because the digestive or processing time would be very large (if, of course, they could digest us at all).
Incompatibility (assuming alien life started-out its evolution with different chemicals in the atmosphere to what we had on Earth): Proteins, carbohydrates and sugars all 'make sense' to animal digestive systems because all life on Earth has evolved from common sources, in an environment rich in their constituent molecules. On an alien planet where advanced life has evolved, if the starting-point was different, the nature of life's building-blocks will be different. Duplicating molecules, the stuff that causes evolution, grows up to use the molecules that are available. The environment shapes the resultant structure of life. We cannot eat silicon-based chemicals, but we can digest carbon-based ones. If a hot planet produces aliens that eat silicon, they might find all life on Earth to be far too insubstantial, and all but inedible. Given the fussiness of what we can eat, and even the dangerous nature of eating food that is too far removed from our historical diets (i.e., fish, plants, small animals, etc), we could probably not eat life that didn't evolve on Earth, nor could they eat us.
But despite these formidable problems, there is another possibility. We know that life can evolve on planets where carbon and other CHOMSP chemicals are abundant and available. It might be that this particular combination is the only efficient way for life to evolve. Of all the planets, life might only evolve on those with the right mix of chemicals. These means that all life could be comprised of many similar chemicals to ours. Not only might there be aliens that can digest us... but all aliens might all be able to digest each other, including us! Although this means that universal cuisine is going to be much more fascinating than planet-by-planet dishes, it also means we haven't quite finished our examination of whether aliens will eat us.
Sometimes, Humans eat each other. We tend to be a food-orientated species. Meals, cooking, meats, sauces, all kinds of plant life and fish, are palatable to us. It might be that we see no reason why we can't eat aliens. Some of us, I dare say, would strive to do so. Some aliens might be similar to some Humans: They would love to find out what an alien tastes like! And, legal or illegal, moral or immoral, they might proceed to do so! What if, then, the first aliens that discover Earth are a species, or even just a group of rogues, who are searching in particular for things to eat? And what if life in the universe is largely carbon-based, and we're edible? Perhaps we would engage in some prisoner exchanges, where instead of cremating criminals who have been executed, we part-exchange them for alien meat!
But, rogues aside, I think it more likely that the more organized alien species are the ones likely to find us, and also these species are less likely to have rogue spaceships wondering around. The foremost evolutionary biologist, Prof. Richard Dawkins, points out (2006) that as species-bias decreases in advanced species, we will seek more and more to avoid harming all other animals. This process is of course evident in Earth history. Alien neurology will lead them to understand that animals and foreign species have feelings like theirs, and will eventually evolve culturally to a point where they seek to avoid pain and harm to others. As a result, the chances are alien governments will not try to eat us. Observe the way that the most advanced countries are the least barbaric, and have the most processed, unnatural foods. If this continues, we will stop eating anything that comes from living material. If aliens continue to evolve technologically, they will likely arrive at the same point. Space travel, especially, requires long-term sustenance on non-living food. Advanced space travellers will probably not eat us, after all, and their governments will probably reign-in any rogue aliens that do try to, just like Human societies monitor their own cannibals and bloodsports practitioners.
So in summary: It is unlikely that aliens would be able to obtain enough energy from us efficiently in order to need to eat us. In addition, if life evolves under various conditions in the universe, aliens will probably have a biochemical make-up so different from ours that we are mutually inedible and potentially very poisonous to each other. But, if life all over the universe is carbon-based and can not evolve elsewise, we might find aliens can digest us (or us them). However, as advanced society relies less on living food and increasingly processes its food, and continue towards non-violence and non-harm towards an increasing range of animals (apes, baboons, Yorkshiremen, etc), and space-travel is (probably) only possible if you can survive on such processed food, it is very likely that space-faring aliens will not be seeking to eat us. Especially as advanced species probably watch out for transgressions amongst themselves, just like advanced moral countries prevent animal cruelty and bloodsports. In short, if we find aliens they probably can't eat us, and wouldn't.
Now, enough about aliens, and back on to purely Earthly and Human concerns, although concerns that are of no less a spurious and otherworldly nature.
A good god could, if it wanted to, have designed all life so that it is directly sustained by manna from heaven, with no need for consumption of biological matter. But almost every form of life must by its very nature capture, kill and eat other living beings in order to survive. Without this murderous torment, life is impossible. If not by direct consumption, then, organisms must still acquire biological matter at the expense of others: the competition for food is also a case of living beings being required to outdo each other merely to survive. There is no way to live life along a principal of do no harm.
If life was created, and not simply the result of undirected unconscious evolution, this is surely the worst possible way to have created life. A god could not have created a more vicious cycle if it tried: tying the very existence of life with the necessary killing of other life is the work of an evil genius, not of an all-powerful and all-loving god. Either no god ever instigated life or guided it, or, such a god is monstrously evil.
For more, see:
Small animals feed on insects. Large animal predators feed on small predators. This is natural. This is normal. We are not surprised when, one level up, we find that we eat "lower" animals, such as rabbits. It's how it is. Our intelligence and development has made us the arbiter of life on this planet. We value Human lives much more than animal life. So, we side strongly with the survivors of zombie plagues and we feel they have every right to survive by killing zombies, because the living are so much better than them. Through several levels of the food chain, we are happy to admit that it is normal for the higher species to use lower species. But why, then, do we draw the line at our level? Vampires, and the elite, are a level better than the untermensch, so why are we appalled when "they" use us according to the natural laws that we accept? We accept natural laws to justify our using of lower species, so how come we find it so repugnant when higher species use us? The reason is that our justification for the food chain is fake; the real reason is necessity. We will do what it takes to keep on top. Likewise, so will vampires. And so will the human survivors of zombie films: They will kill, in order to keep in power.
Zombie and vampire films therefore, teach us much about humanity and the will to power. We learn that the 'natural laws' that we use to justify our existence at the top of the food chain are not the real justifications, and that we are simply self-interested, species-biased and paradigm-biased. Anything better than us we fight against, and anything weaker than us we exploit.
For more, see:
Prof. Richard Dawkins, a foremost biologist and expert in evolution, explains that Human culture has a history of species-ism:
“The feeling that members of one's own species deserve special moral consideration as compared with members of other species is old and deep. Killing people outside war is the most seriously regarded crime ordinarily committed. The only thing more strongly forbidden by our culture is eating people (even if they are already dead). We enjoy eating members of other species, however. [...] We cheerfully countenance the shooting without trial of fairly mild animal pests. Indeed we kill members of other harmless species as a means of recreation and amusement. A human foetus, with no more human feeling than an amoeba, enjoys a reverence and legal protection far in excess of those granted to an adult chimpanzee. [...] The foetus belongs to our own species, and is instantly accorded special privileges and rights because of it.”
The Skeptical Inquirer magazine is famous for its careful facts-only analyses. Their summary of the state of GM food in Europe reads:
“In Europe, only one genetically modified (GM) plant variety is cultivated: the insect-resistant Bt GM maize. Even so, its cultivation is still very controversial. [...] Opponents to the use of biotechnology in agriculture are still very aggressive, particularly in France. They seek to ban all GM food for humans and animals. Greenpeace and the well-known neoluddite José Bové are heavily lobbying both the French government and European commissioners. [...]
More than 500 scientists from French and European public research organisations [signed a declaration to] affirm that any new plant variety, genetically modified or not, should be considered only on a case-by-case basis. They note, and specialized committees throughout the world agree, that the insecticidal active compound present in Bt GM maize has been exploited for decades by conventional and organic gardeners without any observable toxic or allergic response. [...] These signatories state that the "No to GMO" campaign is based only on imaginary or false uncertainties.”
And around the world:
“25 countries now grow GM crops, with the total area under cultivation now larger than Peru. Three-quarters of the farmland used to grow soya is now sown with a genetically modified variant, and the figures for cotton are not far behind. [...] Such stories of success will strike fear into some hearts [...] but lacking supporting evidence they have never been compelling. On safety, the fear which cuts closest to home, the record continues to look good.”
The Economist (2010)9
A particularly forceful defence of the safe nature of GM food was given by Lord Tavern:
“As argued in other essays in this volume, there is no evidence that GM crops have ever damaged human health, while they have already shown substantial benefits to some of the world's poorest farmers and can potentially make a huge contribution to the reduction of poverty, hunger and disease. Over five million small farmers in China, India, South Africa and elsewhere now farm GM cotton. Not only has their income been substantially increased by savings from the reduced use of pesticides, but their health has also improved. These are actual, proven benefits.[...]
There is no reason to regard GM crops as less safe for human consumption than conventional crops: this is the opinion of [four] Royal Society reports, one report by seven international academies of sciences, as well as any number of reports by prestigious committees, including two by the Nuffield Council of Bioethics (a mixed committee of scientific experts and lay representatives). Nor has any evidence emerged that they will create new 'super-weeds' or that they are especially dangerous to biodiversity.”
Lord Tavern 'The Harm That Pressure Groups Can Do'
In "Panic Nation: Unpicking the Myths We're Told About Food and Health" by Feldman & Marks (2005)10
Synthetic meat, also known as in-vitro meat, is grown in laboratories and vats rather than being the flesh of slaughtered animals11. It has been frequently predicted to be "nearly ready", but research continues and it is clearly at least another ten years away12. When ready, it has "astounding potential to save animals"13.
Without the diseases, contaminations and antibiotics of animal agriculture, it has potential to be healthier11 and more predictable quality than slaughtered meat, avoiding those periodic disease outbreaks that lead to mass culling and supply chain disruptions13. The benefits to animal welfare are epic: no livestock needs to be kept in captivity, it requires no slaughter and no animal transportation, and could stop the hunting of endangered animals for their meat11,14. It is much better for the environment, using 98% less land than animal agriculture and 82-92% less water, up to 60% less energy for equivalents to pork, sheep and beef and producing 80-90% lower greenhouse gas emissions14,13.
But potential isn't matching reality. Synthetic meats are still having to use particularly cruel animal extractions in order to provide growth media; the market is likely to remain experimental and niche for a long time and may never be accepted by vegans13 nor by committed carnivores. It is being comprehensively overtaken by high-quality protein-rich plant-based foods with denser textures. Encouraging plant-based foods seems a winner, whereas synthetic meat is turning out to be too slow to develop, and once done, will remain too expensive to become influential enough to help with reducing unsustainable animal agriculture and animal suffering.
For more, see:
Many religionists, especially conservative Christians in the USA and fundamentalists around the world, oppose Humankind's intervention in genetics. "Some, like Leon Kass, the former head of President Bush's bioethics council, regard genetic interventions as humankind's contemporary replay of the Tower of Babel episode"15. They say we 'shouldn't play God', that genetic engineering is a Promethean seizure of God's power. A poll in 1997 revealed that 70% of Americans said only God should have the power to interfere with inherited traits, following on from polls in the 1980s that saw two-thirds of Americans declare that the altering of human genes was against God's will15.
I will now offer four arguments that genetic engineering is in accordance with God's will - and also offer one cheeky argument that at the very least, genetic engineering foils the Devil's plans! So for those of us who don't believe in such dualisms, take the following with a philosophical pinch of salt:
Firstly, God doesn't have control over inherited traits. If there is a God, and it designed the way nature works, then it relinquished its control of inheritability when it chose to create genes. Genes are subject solely to the deterministic laws of physics and chemistry. These laws run without God's interference; the genes that we inherit result from natural cause and effect in accordance with fixed physical laws, not from God's will. There is only one reason why God would create such roundabout way of facilitating the inheritance of traits: because it wanted to place genetics within the grasp of human biological sciences. If it did not want us to consciously examine and improve our genes, then God would not have made them accessible. Traits would be picked by god and bestowed upon individuals by magic, without a physical intermediary (DNA) doing the job. If God is all-powerful and all-knowing, then DNA exists in the physical world (rather than the spiritual one) for a reason: God has placed DNA within our reach to see what we will do.
The desire to eradicate disease is the desire to help others; it is a moral impulse derived from our best social instincts. The expression of this desire through advanced science provides us with new methods of preventing disease. If God's test is to see if we will do the right thing, then, my bets are with the geneticists. Those who wish to let disease run its course, and let mutant genes continue to cause disease, are the ones who are interfering with God's will. It is God's place to punish humankind for transgressions, not our place to punish ourselves (and those around us) by failing to fight disease and biological dysfunction.
Thirdly, exegesis: Christians will remember that in their 'Old Testament' it implores humankind to govern nature. God has placed DNA within the realm of nature, the same as it placed seeds and plants within our grasp. We took those seeds and plants and selectively bred them to create many crops that over thousands of years, have become intensely genetically modified by us. Consider that the Bible grants us "animal husbandry". There was no phrase in the Hebrew vocabulary for genes or evolution, but husbandry is a sexual term that implies the act of mixing male chromosomes with those of a female egg, to produce life. This is genetic in nature. The next section on this page details advances we have already made with crops and with our creation of domesticated species such as cows, pigs and cats. These animals did not originate in nature - we created them without causing the heaven's to rain fire on the Egyptians or Indians.
“The same Genesis narratives that many read as a source of the prohibition confer on human beings the task of governing and tending to nature. Throughout the Bible, agriculture, animal husbandry, metalworking, and many other technological interventions in nature are permitted and even approved.”
Human achievements with crops and domesticated animals are much more extreme that the simple genetic engineering changes we would implement now, such as removing genes mutations that cause certain diseases, and adding vitamin-producing genes to common crops. This is small fry to what we have already achieved. It's not that the religionists are opposed to the results, it's just that they perceive continued scientific achievements to be a threat to their general religious worldview.
Finally, genetic engineering may aid in the fight against the Devil! Genetic engineering will eventually absolve us of the need to kill livestock to feed ourselves. Researchers have already grown meat in laboratories, from germlines extracted from animals16. Such meat is the real thing, but is grown without the need for a living organism surrounding it. It is maintained by the laboratory as fresh, non-living meat. Manufacturing on reasonable scales in so far impossible, but in the future it will be possible, and the barbaric era of animal slaughter will start to enter history for good. This underlines our final argument. The food chain is designed so that in order to survive, living beings have to kill and destroy each other. The whole food chain is based on blood and death. This is the design of an evil genius, not of a good god. Likewise for gene mutations (which cause the suffering of many innocent and unborn children) and other biological dysfunctions. No good God would have created such a flawed biological world. If it genetics is a chance at dashing the devil's (apparent) designs, then, we should give no hesitation!
“The public furore about health hazards of genetically modified foods rests on no reliable evidence base and falls little short of mass hysteria.”
Sir Peter Lachman (2005)17
People claim to be risk-averse when it comes to highly-tested synthetically grown meat, and genetically modified plant produce, which is known to be safe, but, continue to eat foods that are known to have bad risks. Cancer Research UK report that "experts think that about a quarter of all cancer deaths are caused by unhealthy diets and obesity"18. It is not, therefore, that people mind the risks of meat grown in vats, but, that they don't like new foods. Therefore the opposition to synthetically grown meat is at least partially (or greatly, given the difference between normal risk-taking and GM risk-taking) a result of neophobia. The best course of action against neophobia is simply to slowly introduce the new foods, and let people get used to them over a generation or two.
Another hint that something psychological is going on is the correlation between those in the Eurobarometer poll who said that Humans have a duty to protect nature, and those who think that we should grow synthetic meats so that we no longer have to slaughter (or keep) farm animals. There isn't a correlation between the two groups19. Those who want to protect nature, and animal-rights activists, are largely against the growing of synthetic-natural meats. It would make sense that in order to protect nature, end farm captivity (even if not completely), and end animal slaughter, we should grow food that surpasses the need for those things. The fact that those people are against vat meat must mean that there are additional, psychological components to their opposition. You would think that, given the massive alterations to natural species we have engineered in cattle, and the painful and distorted lives that they lead as a result, would mean that we would wish to change the status quo in food production. Neophobia beats rationalism.
The futurologist Tim Jones does not think that this will always be the case in Europe, especially as world food production continues to stagnate:
“Large-scale farming to feed the world's millions requires more refined crops and this implicitly means wider acceptance of GMO. Several workshop participants saw that, by 2020, GM crops will be accepted globally and that regulatory bodies such as the EU will have significantly loosened restrictions on them.”
Diet has an impact on health and affects the risk of disease21. Over the last few decades biochemical and other sciences, from neural to gastric, have made impressive contributions to our knowledge22. Never before have scientists known so much about food and nutrition. Unfortunately much of this knowledge is not reported by the popular press and news outlets because it is technical, mundane and statistical in nature. The average consumer mostly hears only the sensational claims of pseudoscientific sham researchers and promoters, which are often paid for and orchestrated by the rich food industry itself. The two most misleading sources of information are reports based on single-studies and TV adverts. Most people are ill-informed about diet and health as a result of this.
There have been a long series of temporarily popular fad diets which limit food intake to a specific range of items, sometimes cutting out essential fats and proteins completely. They emphasize rapid short-term change at the expense of medium and long-term issues. Of the independent scientific studies on fad diets, supplements, mega-vitamins and similar highly-hyped abnormal sources of nutrition, all have found them to be useless and sometimes actually harmful. The National Health Service (UK) warns that "many fad diets are based on dodgy science or no research at all, prescribing eating practices that are unhealthy and can make you ill"23. The boring truth is that only well-rounded diets are truly effective at long-term weight management with only the very basic advice being effective: cut down on fats and salts, cut down on sugary and fizzy drinks, and eat plenty of wholegrain food, fruit and vegetables (5 portions a day), and drink ordinary water.24,23
Fads rely on testimonials and public-relations tricks to make themselves sound effective and claims are often based on (easily biased) single-studies rather than on independently verified and duplicated scientific trials. The mass media love reporting on these single-studies as their claims are often outlandish and celebrity endorsements boost a fad diet from time to time. Fad diets distract people from sensible eating habits. Rather than accept enthusiastic praise from soap stars, models and newspaper advertisements, it is doctors and the medical profession that we should trust to keep us informed. Let's stop falling for these tricks!
For more, see:
What appears at first to be a purely technical matter; studying the rise of energy from basic single-cell life forms through the trophic levels to the predators that gather food over massive areas, can lead us to some serious exobiological, philosophical and even theological debates. Firstly, advanced alien life is likely to find it hard to gain enough energy to survive from digesting us alone, so probably won't be inclined to try. But alien life may well use different metabolic pathways and different biological chemicals so we may find each other utterly inedible and potentially very poisonous. If life in the universe is generally carbon-based, then, it is possible aliens could digest at least parts of us. But they probably won't, as space-faring advanced species have probably out-grown genuine carnivorous diets, as perhaps we are doing by relying on increasingly processed food (eventually grown in vats) coupled with increasing care for animal rights. Now, dietary exobiology aside, the very fact that life evolved from its unconscious, automatic beginnings, to rely on a cycle of life and death (where life survives by killing other life) indicates that if the cycle of life has a 'designer', such a God is an evil one. Only an evil God would design life so that to stay alive, animals have to kill other animals. This 'victory of death' is the exact opposite of what a good god would have designed, where all animals and plants survive on mystical energy from heaven without need for killing or competing for food (a mythical 'victory of life').