“When the facts change I change my mind” remarked JM Keynes. He was an economist, but his words presciently introduce the whole basis of the scientific method. Two examples of this working beautifully come both from today’s Guardian.
In the first example the discovery of a humble little fish fossil, called Minjinia turgensis, which is about 410 million years old, upends all our theories about how vertebrates evolved.* Every schoolchild was taught: first came little creatures like lancelets, then simple fish called placoderms with skeletons made of soft cartilage. Sharks, rays and the rock salmon beloved of the British fish and chip shop kept this design. Later on other fishes (think cod, haddock or trout) evolved a skeleton of bone. Now it seems Minjinia too had a skeleton of bone, implying that this came first, and our cartiliginous friends lost theirs later on the way. Another way in which a new discovery upsets the apple cart.
Talking of apple carts, are we missing something in the hunt for life on other worlds? Is our thinking too constrained? Is life always based on water? Does it have to follow the laws of Darwinian Natural Selection? Stuart Bartlett and James Wong of the University of Washington propose a broader definition of something called lyfe, which may help us spread the net further. According to them , lyfe:
1 Draws energy sources from the environment 2 Grows exponentially 3 regulates itself 4 learns and remembers things about its environment
Experts and scholars have been drawing up lists of things for centuries but if this helps even a little, we think it’s worth pursuing. Remember: nothing is so well hidden as things which are hiding in plain sight.
#astrobiology #life #bonyfish #evolution #vertebrates