The Past is a Big Country
Contemplating the Trans-Canada Timeline
In the past few weeks there seems to have been a lot of discussion of evolution in the popular press. Or rather, there has not been an awful lot about evolution per se, but there has been quite a bit of conversation concerning the recent debate between Bill Nye and Ken Ham on the relative merits of the Theory of Evolution vs. a literal biblical interpretation of the history of life.
I won’t go into the outcomes of the debate, but many of the things that were said got me thinking about the average person’s understanding of the history of our planet. In the discussion of Ham vs. Nye, it was often pointed out that about 40-50% of Americans believe that the Earth was divinely created, with a good few of them being young Earth creationists who insist that the planet is in the range of 5,700 to 10,000 years old (the percentage in Canada would be somewhat lower, but still substantial). While the thinking of young Earth creationists seems abundantly clear, it is far less certain what most other people think about when they contemplate Earth History. Do they have any clear ideas to replace the reassurance given to those who possess absolute faith?
Over the past couple of centuries, science has learned a tremendous amount about the history of Earth and life. Our scientific understanding of these issues is based on an immense amount of painstakingly-gathered data; the raw data, if printed, would fill many warehouses. When we say that the Earth is 4.54 billion years old, and when we say that life on this planet has evolved, these are facts, readily observed from the basic data.
Although scientific information is easily available in our modern age, it seems that many people are quite unaware of it. In my dealings with the public I have been fascinated to discover that, among people who apparently accept evolution and an ancient Earth, there are many who lack any basic comprehension of the scale and complexity of geological time.
For example, I often encounter people who know that water covered southern Manitoba in the past. They tend to think that this happened only once, when glacial Lake Agassiz occupied the middle of the continent at the end of the last Ice Age (in the range of 12,000-8,000 years ago). On the basis of this one piece of knowledge, their brains shoehorn all ancient underwater deposits and fossils into “Lake Agassiz”, everything from the Ordovician Tyndall Stone (about 450 million years old) to the Late Cretaceous marine reptiles of the Manitoba Escarpment (roughly 100 million to 70 million years old), to the actual Lake Agassiz clay deposits.
I suspect that this is partly because they were taught very little about geological time in their school years, but it is also a fact that many North Americans are brought up to be lazy thinkers, and we are content to adopt simple (mis)understandings of the world. This is a shame, as knowledge of geological time is so critical to understanding one’s place in the universe, as well as more practical considerations such as environmental change and the search for resources.
It has been said that “the past is another country”.* For most people, it seems that that other country is a small and vaguely familiar place, familiar in the same way as the pictures in old dog-eared National Geographics that you might have once skimmed in the dentist’s waiting room. The country might be visualized as being about the size of Monaco, somewhere you could see across readily if you wish, or walk through in an afternoon. In that little landscape can be found all the familiar reconstructions of past life: the paintings of Precambrian volcanoes, the museum dioramas of Paleozoic reefs, the dinosaurs of Jurassic Park, the Ice Age mammoths and Smilodon. Since the country is so small, of course some of the things are going to get jumbled and mixed up: the cave men with dinosaurs in Hollywood epics and Flintstones cartoons would be the most familiar examples of this. Now remember, this is the general view even among many members of the western public who accept that the Earth is old and that life has evolved; for the young Earth creationists, the country has to be even smaller, about the size of a kitchen.
The past, however, is not that sort of cozy little country at all. It is more like the places you see depicted on old maps, where “here there be dragons” and ships can sail off the end of the world. It is a place of adventures, of great catastrophes and miraculous survivals.
Let’s take this spatial comparison a bit further; let’s convert time into distance and see how it plots on the map of a real, big country. As a Canadian I of course had to choose Canada, which turns out to be fortunate. The distance coast-to-coast from Vancouver, British Columbia to St. John’s, Newfoundland, is about 7450 km. Converted to Imperial units, that is roughly 4630 miles, which allows a very ready comparison with the Earth’s age of 4.54 billion years (i.e., 4540 million years). Thus, within a 2% margin of error we can plot geological time along a route across Canada, with a scale of 1 mile = 1 million years. This follows the Trans-Canada Highway, so let’s call it the Trans-Canada Timeline.**
If we say that the present day is at the shore of the Pacific in Stanley Park, we don’t have to travel very far to get back into prehistory. Jesus lived about 2000 years ago, which on our trans-Canada scale would be 3.2 metres (10.5 feet) along the time route, or maybe somewhat less than the width of the footpath beside the sea wall. The 10,000 years since the last Ice Age would measure out to about the width of a highway, and of course we are still just barely into Stanley Park.
Rather than recent prehistory, let’s consider the deeper prehistory of human relatives. Lucy, one of the earliest well-preserved hominids, found in Afar, Ethiopia, has been dated to about 3.2 million years old. On our Trans-Canada Timeline, we have now travelled from Stanley Park to downtown Vancouver, somewhere around the BC Place Stadium. To get properly out of Vancouver, we are going to have to get into some deep time, and remember that there is still all the rest of Canada to be accounted for!
Driving eastward up the Fraser Valley, we pass rapidly through the “Age of Mammals” (Cenozoic Era) on our time/country comparison. The extinction of the dinosaurs at the end of the Cretaceous Period is reached in 66 miles, at about Chilliwack, while the very first dinosaurs are near Kamloops in the BC Interior. For the remainder of British Columbia we are passing backward through the earlier parts of the Phanerozoic Eon (the time of “visible life” on Earth). The ups and downs of mountains and valleys could be compared to the ups and downs of diversification and extinction of life forms, with events such as the movement of life onto land and the origins of amphibians and reptiles.
The end of the Cambrian explosion, the interval in which many major groups (phyla) of animals first evolved about 541-485 million years ago, is appropriately reached just east of the localities for the famous Burgess Shale near Field, BC, while the beginning of the Cambrian is over the border near Canmore, Alberta. So our Trans-Canada Timeline is still in the western mountains and we have “already” reached the beginnings of all the animal groups with which we are familiar. Down the road we see the Ediacaran Period (635-541 million years ago) between Canmore and the eastern side of Calgary, and the Cryogenian Period (“snowball Earth”) from Calgary to somewhere near Maple Creek, Saskatchewan. Anyone who has driven through prairie snows will find this location entirely appropriate.
Now, let’s cover some territory. We are already getting well back into the Precambrian, and we still have a lot of country ahead of us! At Winnipeg we are solidly in the mid-Proterozoic, which could be called the “age of stromatolites”, as it was in this interval that algal and microbial mats reached their greatest abundance and diversity.
The first eukaryotic cells (complex cells that contain a nucleus and other structures) evolved about two billion years ago, which on our time map puts us near Terrace Bay, Ontario, in the middle of Precambrian rocks along the north shore of Lake Superior. Oxygen-producing photosynthesis is a bit earlier, as evidenced by banded iron formations that are 2.3-2.5 billion years old; we have now driven east to the stretch between Blind River and Sudbury, Ontario.
Across eastern Ontario, Québec, and the Maritimes, we are passing back through the Archean, as the earlier part of the Precambrian record is called. Timeline milestones here would include things like the formation of many of the gneisses and schists that can be observed in the Canadian Shield of central Canada. We don’t actually reach the earliest geological record until we have travelled to Newfoundland: the Acasta Gneiss of the Northwest Territories is about four billion years old, which on our Trans-Canada Timeline would place it just after we drive off the ferry at Port aux Basques. Around Gander we pass the formation of the world’s oceans at about 4.4 billion years, and driving into St. John’s we finally reach the formation of the Earth from the accretion of gas and dust.
I contemplate geological time every day, but I still find it mind-boggling to sit down and compile this sort of analogy. On the Trans-Canada Timeline, a human life of 80 years would translate into about 5 inches, or 13 centimetres. Maybe it is no wonder that deep time is so generally ignored in our day-to-day lives, when the geological history of the planet is so many orders of magnitude greater than what we can experience. Nevertheless, we need to find a way to be more mindful of deep time, especially when we think about issues such as the tremendous rate at which we are using fossil fuels, which have taken hundreds of millions of years to form.
With so much knowledge now available to all of us, maybe we can hope that the average person will get an improved understanding of basic science, which could inform future democratic decision-making. With all the distractions available through the same pipe, though, I am doubtful that this will happen. Thinking is hard work; I’m going to go and watch the Olympics now!
© Graham Young, 2014
* The British author L.P. Hartley actually wrote “The past is a foreign country: they do things differently there”, but “The past is another country” seems more prevalent in the vernacular.
** In assembling this piece I used the International Commission on Stratigraphy’s 2013 International Chronostratigraphic Chart.