Thursday, 5 June 2014

TIKTAALIK - OUR CANADIAN TETRAPOD ANCESTOR


         Sorry, Africa, but it is time to relinquish the crown to Canada to hold until it has to give it back to Mars.  Sometime this century?  We do thank you for allowing us to use your trees, your savannahs, and your predators to guide us through some of our growing stages.  We did need those 6 million years with you for our Ardipithecus, Australopithecus, and various Homo stages before leaving for the Middle East, Europe, and Asia.  And, yes, we can increase that to 20 million years if we include our Orangutan and Chimpanzee stages.  Some of us did leave you, starting 1.8 mya (million years ago) as Homo erectus.  It was only 125,000 ya (years ago) when restless Homo sapiens members started leaving.  Some of us are still meandering.
What a mobile creation we are!  If Mars is our next stop we may be completing a cycle because the chances are high that we came from there originally, as tiny prokaryote-cell passengers on a meteorite 3.6 billion years ago.
However, let us pause to add to our genealogical wall chart our time on the world’s 10th largest island -Ellesmere.  For shame, few of us have visited Canada’s second largest national park located on its northern tip, 800km from the North Pole.  I did fly over it in 1947-9, before it was made a park with its spectacular scenery and Lake Hazen, remarking what a great location for a POW camp - no escapes with miles upon miles of ice-covered mountains, fiords, plateaus, and lakes.
     Like the rest of us, Ellesmere Island is not what it used to be, yet in basic format is much closer to its youth than we, giving us much history to explore.  Some 4 billion years ago it was one of the first bits of rock on this planet to poke its head above the molten sea.  It did cool to a tropical retreat so it was ready, 375 mya, to welcome Tiktaalik, a foolish teenager bent on adventure or, more likely, a girl chased by boys, who dared to use her four flippers to ease herself up onto a beach out of their lusty reach.    
     Now, Canada is a much more peaceful land than Africa, or most of the rest of the world for that matter,  so its Ellesmere Island was a huge, predator-free, refuge for Tiktaalik.  But boys, the same for most species, did summon the courage to follow her, resulting in a dozen fossils, ranging in length from 3 to 9 feet, for scientists to find so far with only a tiny fraction of the land examined.
     Knowing the unique preservation of Ellesmere’s ancient soil, scientist started looking there in 1999 for traces of our first use of the amphibian format.  Although currently warming dramatically, digging for fossils is still limited to July and it took five of them before Tiktaalik, a complete and perfectly preserved fossil, was found.  
     Ellesmere Island provided the laboratory for them to evolve into more mobile land tetrapods (4-footed), then wander off to far away places to become you and me.  And, we will continue to evolve if we can find the wisdom and the will to avoid exterminating ourselves and the environment we need.
So, what did we look like 375 million years ago when we were all Canadian tetrapods?
We Canadians were flat headed, much like a crocodile.  Unlike our fish ancestors we had a neck so could move our head without also moving our body.  We were well adapted for life in shallow seas.  We had fins, scales, and gills, but we also had sturdy wrist bones permitting us to raise ourselves from the sea floor to snap at prey.  The transition to life on land, from a brief refuge to a permanent residence, was slow and painful, definite proof as to what a sturdy lot we Canadians are.  For instance our large cranial bone, hyomandibula, that connected our upper jaw to our brain case and helped with gill breathing evolved to where it is now tiny and helps with hearing in our middle ear. Why, Tiktaalik, am I, then, going deaf so young in life? 
     Some 4,000 years ago Tiktaalik returned to northern Ellesmere in the form of palaeo-Eskimos from Siberia via Alaska.  They hunted caribou and musk-ox, but left during the Little Ice Age (1300-1870).  Modern humans did not arrive until the 1800s in the form of European explorers.  Today the population of humans is only 146 of whom 141 are in Grise Fiord on the south coast and 5 (overwintering) at Alert CFB on the north coast.  As I type this (Noon 04 June 2014) the temperature there is zero celsius or 32 Fahrenheit with 80% humidity.  It is 3 degrees celsius at Grise Fiord.  The Eureka weather station is now unmanned. 
      Man-made climate change is dramatic.  90% of the coastal ice sheet has been lost as well as the habitat for some species of waterfowl, invertebrates, algae, and marine life.  Yet another big change is in the making.
     All of you Tiktaaliks are destined for museums while we who put you there ponder what thanks, or blame, we need to give you for your role in making us what we are.
Ye Olde Scribe who is not all that happy when he looks in a mirror.

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