The wonder of evolution
December 8th 2008 13:28
There is an underlying, deep and haunting wonder about biology that all biologists (whether professional or aspiring) are familiar with. In biology, one is dealing with systems that work according to a type of logic but that nevertheless lacks a conscious logician directing it all. It is a sort of emergent logic that arises from the interplay of entities that exhibit a few simple features but that, once these features are actualised, end up producing entities that are stranger and more awe-inspiring than even our most advanced technology. Biological machines - organisms, organs, cells, ribosomes, enzymes - can, like human-made machines, be said to function in the furtherance of a purpose. The purpose of a bat's echolocation is to allow it find its prey; the purpose of a pheromone is to attract a mate. The truly wonderful thing about all this is that the rationality, as one might call it, that we see in these entities is the result of natural processes that are themselves unconscious and blind but extremely powerful. They are so powerful that they produce things of incredible complexity that have baffled us for centuries but that are only now being understood in any significant detail. The imperative behind all biological machinery is the propagation of DNA (or RNA, in the case of many viruses). That is the utility function of the complex pieces of apparatus that make up the living world.
Understanding how this actually happens is one of the greatest joys available to the human psyche. A species has come of age when it understands the forces that have produced it - that is, how its existence is tied in with the rest of nature, and how nature has, through countless eons, produced creatures capable of asking questions like "What's it all about?" Evolution, perhaps the most stunning discovery ever made, is that process. It is a process of change - fortuitous, gradual, episodic, uneven, but with a regularity called "natural selection". It is also a story - the grandest story we know of, spanning three and a half billion years, comprising countless lost dynasties, false starts and dead ends, close calls and great flowerings, eternal partnerships and eternal rivalries, shaky alliances and squabbling companions. It is a story often times punctuated by cataclysm, often times by enduring stasis, of repetition and reinvention, and novelty and opportunism. It's rich beyond measure, fascinating like nothing else, and important enough to deserve no less than a fully naturalistic explanation. I have spoken about evolution as though it were poetry, and in a way it is. Certainly, it is haunting and mind-expanding enough to warrant the very finest that poetry can deliver, and its telling must be available to every person on the planet so that they can share in its wonder.
Evolution is humbling, too. It chips away - often insults - our anthropocentric yearning to be the centre of everything. It has no time for our parochialism. The tiny virus that infects our cells changes and adapts with no ear to our suffering. if it eases that suffering through subsequent changes, that is incidental; propagation of the genetic code is all. But evolution is not actually cruel, merely indifferent to our angst. It has produced us, true, but it has equipped us with cognitive faculties that, as a side-consequence, make it difficult for us to come to terms with it and its ramifications. For all that, though, evolution robs of us nothing that makes life worth living. Our human dignity is left fully intact; it's just that we sometimes have to place that that dignity on different - albeit more secure and sober - foundations that give us a more nuanced appreciation for what it means to be human. And the more we investigate and discover, the more peculiar everything turns out to be. We discover that we share most of our genome with other primates. Then we discover that we are more closely related to chimpanzees than chimpanzees are to gorillas. Next we find that our genomes are composed largely of defunct viruses and virus-like entities. There is no limit to the sheer strangeness of life, how it turns our preconceived notions on their (ultimately insignificant) heads. Science fiction struggles to keep pace with true science in terms of weirdness, and while one can't predict what discoveries will be made in the future, one can safely assume that those discoveries will often times be so weird that they leave us stunned, even a little disturbed. And that's really what the biologist lives for - the possibility of discovering something so bizarre that, even after it is comfortably assimilated into the mainstream, staggers the mind to quietly reflect upon later.
Think about this: a parasitoid wasp (there are thousands of species of these incredible insects) injects its host with not only its egg, but also an agent that paralyses it so that the unfortunate victim will stay put while the hatchling inside it consumes it alive. But that's not all. The wasp also injects a virus that neutralises the immune system of the host. These viruses are known as polydnaviruses, and they are actually intergrated into the genome of the wasp, activated only in cells of the female ovaries. These viruses appear to be related to others that are transmitted through the conventional route, as well as to viruses that are transmitted by wasps but that are not integrated into the genome. Moreover, this symbiotic system appears to have evolved at least twice independently in two wasp families. They have clear differences reflecting their separate origins, but also some stunning convergences in their design that speak to the power of evolution to reinvent. Finally, these viruses are present in thousands of species. They are so well adapted as immune-disabling vehicles that they are properly not seen as viruses any more but rather wasp organelles (though, even more intriguing, it is possible that they are actually manipulating the wasps to serve them, with the wasps acting, effectively as giant organelles of their own). We even know that this symbiosis is ancient, having originated at least tens of millions of years ago. The parasitoid wasps with their polydnaviruses are my choice for illustrating the almost perverse fascination of evolutionary strangeness.
So there you have it. Evolution is the richest science around, and it is itself rapidly evolving. It incorporates - indeed, is largely a bastardisation of - mathematics and statistics, chemistry, genetics, engineering, information theory, geology, geography, and of course zoology. And as our species leaves an ever more significant footprint on the planet, a thorough knowledge of it will become vital to alleviating this pressure on the other inhabitants of this planet, and thereby to help ensure our own survival.
Understanding how this actually happens is one of the greatest joys available to the human psyche. A species has come of age when it understands the forces that have produced it - that is, how its existence is tied in with the rest of nature, and how nature has, through countless eons, produced creatures capable of asking questions like "What's it all about?" Evolution, perhaps the most stunning discovery ever made, is that process. It is a process of change - fortuitous, gradual, episodic, uneven, but with a regularity called "natural selection". It is also a story - the grandest story we know of, spanning three and a half billion years, comprising countless lost dynasties, false starts and dead ends, close calls and great flowerings, eternal partnerships and eternal rivalries, shaky alliances and squabbling companions. It is a story often times punctuated by cataclysm, often times by enduring stasis, of repetition and reinvention, and novelty and opportunism. It's rich beyond measure, fascinating like nothing else, and important enough to deserve no less than a fully naturalistic explanation. I have spoken about evolution as though it were poetry, and in a way it is. Certainly, it is haunting and mind-expanding enough to warrant the very finest that poetry can deliver, and its telling must be available to every person on the planet so that they can share in its wonder.
Evolution is humbling, too. It chips away - often insults - our anthropocentric yearning to be the centre of everything. It has no time for our parochialism. The tiny virus that infects our cells changes and adapts with no ear to our suffering. if it eases that suffering through subsequent changes, that is incidental; propagation of the genetic code is all. But evolution is not actually cruel, merely indifferent to our angst. It has produced us, true, but it has equipped us with cognitive faculties that, as a side-consequence, make it difficult for us to come to terms with it and its ramifications. For all that, though, evolution robs of us nothing that makes life worth living. Our human dignity is left fully intact; it's just that we sometimes have to place that that dignity on different - albeit more secure and sober - foundations that give us a more nuanced appreciation for what it means to be human. And the more we investigate and discover, the more peculiar everything turns out to be. We discover that we share most of our genome with other primates. Then we discover that we are more closely related to chimpanzees than chimpanzees are to gorillas. Next we find that our genomes are composed largely of defunct viruses and virus-like entities. There is no limit to the sheer strangeness of life, how it turns our preconceived notions on their (ultimately insignificant) heads. Science fiction struggles to keep pace with true science in terms of weirdness, and while one can't predict what discoveries will be made in the future, one can safely assume that those discoveries will often times be so weird that they leave us stunned, even a little disturbed. And that's really what the biologist lives for - the possibility of discovering something so bizarre that, even after it is comfortably assimilated into the mainstream, staggers the mind to quietly reflect upon later.
Think about this: a parasitoid wasp (there are thousands of species of these incredible insects) injects its host with not only its egg, but also an agent that paralyses it so that the unfortunate victim will stay put while the hatchling inside it consumes it alive. But that's not all. The wasp also injects a virus that neutralises the immune system of the host. These viruses are known as polydnaviruses, and they are actually intergrated into the genome of the wasp, activated only in cells of the female ovaries. These viruses appear to be related to others that are transmitted through the conventional route, as well as to viruses that are transmitted by wasps but that are not integrated into the genome. Moreover, this symbiotic system appears to have evolved at least twice independently in two wasp families. They have clear differences reflecting their separate origins, but also some stunning convergences in their design that speak to the power of evolution to reinvent. Finally, these viruses are present in thousands of species. They are so well adapted as immune-disabling vehicles that they are properly not seen as viruses any more but rather wasp organelles (though, even more intriguing, it is possible that they are actually manipulating the wasps to serve them, with the wasps acting, effectively as giant organelles of their own). We even know that this symbiosis is ancient, having originated at least tens of millions of years ago. The parasitoid wasps with their polydnaviruses are my choice for illustrating the almost perverse fascination of evolutionary strangeness.
So there you have it. Evolution is the richest science around, and it is itself rapidly evolving. It incorporates - indeed, is largely a bastardisation of - mathematics and statistics, chemistry, genetics, engineering, information theory, geology, geography, and of course zoology. And as our species leaves an ever more significant footprint on the planet, a thorough knowledge of it will become vital to alleviating this pressure on the other inhabitants of this planet, and thereby to help ensure our own survival.
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