The microbe Lokiarchaeota is a hodgepodge of disparate elements resembling the three Domains of Life, some of which we share. One of the great triumphs of our understanding of life is that the eukaryotic cell, your kind of cell, is an ancient fusion through symbiogenesis of entirely disparate life forms. The power of this kind of imagery in science could not have been more starkly revealed than in the positioning of Lokiarchaeota as a missing link in such a fictional chain. Any of the nodes in a family tree can be rotated without changing the correct relationships among the present-day members – the rotation on the left is the usual one just because we like to be on top! But we know people are not a link between fish and frogs in any meaningful sense. The Great Chain of Being is ingrained enough that it's even become a way for comedy and cartoons to mock the zeitgeist.īoth are correct and show exactly the same information about the relationships – humans are more closely related to monkeys than both are related to lizards than all are related to frogs, and so on. The idea is that, step by step, life continually "advanced" to gain greater and greater complexity. On the left of this figure is the usual picture of life on Earth, a chain of creatures smoothly lined up from fish, through frogs, lizards and on up to human beings. It is compelling – not least because you-know-who winds up at the presumed pinnacle of evolution. The notion of missing links in evolution comes from medieval theology's Great Chain of Being, an idea that survived Darwin and still persists. But it's wrong – and can detrimentally influence our understanding of immediately threatening processes like the rapid evolution of flu. This missing link imagery, based on the idea that evolution is a methodical process with logical, continuous connections to be discovered and mapped, might set up a good story.
0 Comments
Leave a Reply. |