Fossilized tree discovered at N.S. cliff on display at Royal Ontario Museum
310-million-year-old tree one of several fossils exhibited at Dawn of Life gallery in Toronto
An ancient tree that began its modern journey after falling out of a cliff in Nova Scotia is now on display in a new gallery in one of the busiest museums in the country.
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 those fossils is an irregular column discovered at the fossil cliffs at Joggins, N.S. It's a fossilized tree that dates back to the Carboniferous era, when the cliffs that now line the Bay of Fundy were an equatorial swamp at the heart of the supercontinent Pangea.
The 310-million-year-old tree is now part of a permanent ROM exhibit that traces life from its earliest origins, four billion years in the past, to the appearance of the first dinosaurs and mammals about 200 million years ago.
"Across Canada, you'll find sites that speak well to fossils," said Jordan LeBlanc, director of operations at the Joggins Fossil Institute. "I love that we are represented there as well — Joggins is represented with the best."
'You reflect on how old life is'
The Dawn of Life gallery draws on Canada's high proportion of UNESCO world heritage sites to trace life from its oldest known evidence.
"This is something that is really often neglected in museums across the world," said Jean-Bernard Caron, the Richard M. Ivey Curator of Invertebrate Palaeontology at the ROM.
The gallery begins with a single-celled organism from approximately four billion years ago, which scientists call LUCA and which was found in Quebec.
"As you look at this piece, you reflect on how old life is and how we are all connected to a single ancestor," said Caron.
From there, the gallery moves through fossils from Canada's UNESCO sites, from the early organisms found at Mistaken Point, in Newfoundland, where traces of some of the first examples of multicellular life forms are found, to the Burgess Shale in the Rocky Mountains in British Columbia, which tells the story of the origin of animals in what's known as the Cambrian explosion.
"Basically, the roots of our modern world can be traced to the Burgess Shale," said Caron.
Fossils from a third UNESCO site — Miguasha National Park in eastern Quebec — show important developments from the "age of fishes," including fossils of fish that would give rise to four-legged, land-based animals from approximately 370 million years ago.
Finally, the gallery leads to the Carboniferous period, where the stump from Joggins serves as a centrepiece, Caron said.
A puzzle piece in our understanding
Trees in that period, unlike those today, had rigid exteriors and fibrous centres. When those centres rotted away, it left a hollow tube into which sand or mud would once have poured, eventually forming the kind of column that now sits in the ROM.
This type of "cast and mould" fossil is common at Joggins, although not many are as large, and dates back to a time when tropical rainforests first appeared on the planet, contributing oxygen to the atmosphere that allowed large organisms to flourish.
But this period isn't only significant to the history of life, it's 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 Joggins fossil cliffs.
"It was in those rainforests that the evolution from amphibians to reptiles happened and is recorded," Calder said. "And Joggins happens to have the oldest example, in the fossil record of reptiles, of this seminal step in the evolution or branching of the tree of life."
About 300 million years ago, a number of these early reptiles either fell into the hollow trunks of trees at Joggins, or — Calder's favourite theory — were using them as dens, when they were buried by mud and sand.
In the mid-1800s, Charles Lyell, a Scottish geologist and pioneer of modern geology, was walking the beach at Joggins 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 go on to refer to Joggins in On the Origin of Species — and played a role in shaping the understanding of evolution.
Exalting 'the wonders and importance of nature'
Calder said it's gratifying to see Joggins shaping that understanding once again by appearing in the ROM's Dawn of Life gallery, in part because of the relationship between Joggins and 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 has given him the title "the keeper of the cliffs."
"Here's an ex-coal miner who [took] his love of the place he lived in, before others really stepped up to do something, to do the proper recognition of Joggins. He was there, he and his family, and others at Joggins before him," Calder said.
"And this is the same elsewhere around Nova Scotia. There are people that care, and they get the wonders and importance of nature in the broad sense in Nova Scotia, and what we have to offer, and it's those everyday people who really make it work."
Calder said Reid would have been "thrilled" to see the tree, and the care that went into it, now reaching an even broader audience with the opening of the Dawn of Life gallery.
"He was all about sharing the story of the wonders of Joggins, and so he would be tickled pink to have that tree that he had collected on display at the ROM — and to me that's really what's special."
Billions of years in the making
The gallery is opening after a summer and fall of extreme weather events linked to climate change and amid the ongoing instability caused by the pandemic. Caron, the ROM curator, said it's a way for people to understand what happened in the past, and a reminder of the fragility of life.
"It took billions of years, sometimes, to create the organisms that we see today," Caron said. "And it's actually very fragile in the sense that you can destroy these life forms, which carry all this history in themselves, in the blink of an eye."
He said there have been several mass extinction events in the history of life of Earth, including ones that are represented in the gallery. But none happened with the speed — or because of a single species — as the changes we're witnessing now.
"The fossil record in this gallery hopefully gives the visitor a way to reflect on the big challenges that we're facing today," Caron said. "And hopefully, to understand and to value what life is, and hopefully to protect it as well."