An ancient tree that began its modern journey after falling off a cliff in Nova Scotia is now on display in a new gallery at one of the country’s busiest museums.
After decades of preparation, the Dawn of Life Gallery opened this month at the Royal Ontario Museum in Toronto, bringing together a unique collection of fossils from UNESCO World Heritage sites across the country.
One of these fossils is an irregular column found in the Fossil Cliffs of Joggins, Nova Scotia. It’s a fossilized tree that dates back to the Carboniferous Era, when the cliffs that now border the Bay of Fundy were an equatorial swamp in the heart of the Pangea supercontinent.
The 310-million-year-old tree is now part of a permanent ROM exhibit that traces life from its earliest origins four billion years ago to the appearance of the first dinosaurs and mammals about 200 million years ago.
âAll over Canada you will find sites that talk a lot about fossils,â said Jordan LeBlanc, director of operations at the Joggins Fossil Institute. “I like that we are represented there too – Joggins is represented with the best.”
‘You reflect on the old life’
The Dawn of Life Gallery draws on the high proportion of UNESCO World Heritage sites in Canada (four) to trace life from its earliest known evidence.
âThis is something that is very often overlooked in museums around the world,â said Jean-Bernard Caron, Richard M. Ivey curator of invertebrate paleontology at ROM.
The gallery begins with a one-celled organism about four billion years old, which scientists call LUCA and which was found in Quebec.
âAs you look at this piece, you are reflecting on the old life and how we are all related to one ancestor,â Caron said.
From there, the gallery travels through fossils of Canadian UNESCO sites, of the earliest organisms found at Mistaken Point, Newfoundland, where traces of some of the earliest examples of multicellular life forms can be found, to the Burgess Shale in the foothills of the Rockies. in British Columbia, which tells the story of the origin of animals in what is known as the Cambrian Explosion.
âBasically, the roots of our modern world go back to the Burgess Shale,â Caron said.
Fossils from a third UNESCO site – Parc national de Miguasha in eastern Quebec – show significant developments since the “Age of Fish”, including fossils of fish believed to give birth to terrestrial animals on all fours about 370 million years ago.
Finally, the gallery leads to the Carboniferous Period, where the Joggins stump serves as a centerpiece, Caron said.
A puzzle piece in our understanding
Trees from this period, unlike those today, had rigid exteriors and fibrous centers. When these centers rotted, it left a hollow tube that sand or mud would once have poured into, ultimately forming the kind of column that is now in the ROM.
This type of “cast-and-cast” fossil is common in Joggins, although few are this large, and dates back to a time when tropical rainforests first appeared on the planet, providing oxygen. to the atmosphere, which has allowed large organisms to thrive.
But this period is not only important for the history of life, it is also a crucial part of our understanding of that history, said John Calder, a geologist and paleontologist who has worked for much of his career on the fossil cliffs of Joggins.
âIt is in these tropical rainforests that the evolution from amphibians to reptiles has happened and is being recorded,â Calder said. “And Joggins happens to have the oldest example, in the fossil record of reptiles, of this seminal stage in the evolution or branching of the tree of life.”
About 300 million years ago a number of these first reptiles either fell into the hollow trunks of trees at Joggins or – Calder’s favorite theory – used them as dens, when they were buried under the mud and sand.
In the mid-1800s, Charles Lyell, a Scottish geologist and pioneer of modern geology, was walking on Joggins Beach and found a fossilized stump containing the bones of one of these reptiles.
The discovery was a sensation – so much so that Charles Darwin would continue to refer to Joggins in About the origin of species – and played a role in understanding evolution.
Exalt “the wonders and importance of nature”
Calder said it was gratifying to see Joggins shape that understanding once again by appearing in the ROM’s Dawn of Life gallery, in part because of Joggins’ relationship with the people of Nova Scotia – and one person. in particular, the late Don Reid.
Several decades ago, Reid found the tree now at the ROM, and Calder gave it the title of “Guardian of the Cliffs.”
“Here is a former coal miner who [took] his love of where he lived, before others really stepped in to do anything, to make Joggins proper recognition. He was there, him and his family, and others in Joggins before him, “Calder said.
“And it’s the same elsewhere in Nova Scotia. There are people who care, and they get the wonders and importance of nature at large in Nova Scotia, and what we have. to offer, and it’s these ordinary people who really make it work. “
Calder said Reid would have been “thrilled” to see the tree and the care taken in it, now reaching an even wider audience with the opening of the Dawn of Life gallery.
“He wanted to share the story of Joggins’ Wonders, so it would be tickled pink to have this tree he had collected on display at the ROM – and to me, that is really what is special.”
Billions of years in the making
The gallery opens after a summer and fall of extreme weather events linked to climate change and amid the continued instability caused by the pandemic. Caron, the curator of the ROM, said it was a way for people to understand what had happened in the past and a reminder of the fragility of life.
âIt has sometimes taken billions of years to create the organisms we see today,â Caron said. “And it’s actually very fragile in the sense that you can destroy these life forms, which carry all of this history within themselves, in the blink of an eye.”
He said there have been several mass extinction events in the history of life on Earth, including those pictured in the gallery. But nothing has happened with speed – or because of a single species – like the changes we are seeing now. (The extinction of the dinosaurs was rapid, but is no longer considered one of the mass extinction events in life history.)
âThe fossil record in this gallery, hopefully, gives the visitor a way to reflect on the great challenges we face today,â said Caron. “And hopefully understand and value what life is, and hopefully protect it as well.”