The Dawn of Life

The Royal Ontario Museum’s exhibit will travel four billion years back in time

The Dawn of Life

Last week, the Royal Ontario Museum (ROM) finalized plans to build The Willner Madge Gallery, Dawn of Life. As its name suggests, the Dawn of Life will feature fossils from the start of life about four billion years ago until the appearance of dinosaurs over 200 million years ago.

Professor in the Department of Ecology & Evolutionary Biology and Department of Earth Sciences Jean-Bernard Caron and his research team travelled to the Burgess Shale and collected some of the fossils that will become a focus of Dawn of Life.

“Without the close relationship we have with U of T, this would not be possible,” said Caron, who is also the Richard M. Ivey Curator of Invertebrate Paleontology at the ROM. “Without students, my collection would be a pile of rocks.”’

Showcasing Canada’s ancient past

The Cambrian Explosion occured 542 million years ago. This period marked the rapid appearance of diversified animals and mineralized fossils.

The Burgess Shale in British Columbia contains a myriad of fossils from the Cambrian period. In particular, the Burgess Shale is known for its intricate preservation of soft-bodied animals. Many of the fossils from this UNESCO World Heritage site provide a wealth of information that cannot be found anywhere else.

Caron initiated the Burgess Shale projects after joining the ROM in 2006, providing insight into Canada’s ancient past.

In addition to the Burgess Shale, fossils from Mistaken Point in Newfoundland, Parc national de Miguasha and Anticosti island in Québec, and Joggins Fossil Cliffs in Nova Scotia will also be on display.

Featured fossils

The fossils in this exhibit are not only relics of the past, but are also representative of Canada’s rich archaeological history.

In 1886, Canadian geologist Richard G. McConnell collected fossils from the Mount Stephen Trilobite Beds in the Canadian Rockies. McConnell ended up with a collection of trilobites, one of the earliest arthropods. But he also recovered fossils that didn’t belong to trilobites. These fossils had unusual appendages and created confusion among researchers who followed in McConnell’s tracks.

In 1892, Joseph Whiteaves described the specimen as a shrimp. In 1911, Charles Walcott found a complete version of the specimen and described it as a sea cucumber. Other researchers throughout the twentieth century described the specimen as a sponge or jellyfish.

It wasn’t until 1985 that researchers Harry Whittington and Derek Briggs described two of the species in full, one of which is Anomalocaris canadensis, a basal arthropod related to spiders and shrimp.

Anomalocaridids were large predators that dominated the Cambrian seas roughly 535 million years ago.

In the 1990s, researchers from the ROM collected several, complete Anomalocaridids specimens. And in 1996, researcher Desmond Collins described Anomalocaris canadensis in detail.

This specimen is one of many treasures that will be on display in Dawn of Life.

PHOTO BY JEAN BERNARD CARON, COURTESY OF THE ROM (Click to Expand)

Visitors will also be able to view banded iron formation — from the Nuvvuagittuq Greenstone Belt in northern Québec — which contains the earliest evidence of life on earth.

PHOTO BY DR. JONATHAN O’NEIL & PITUVIK LANDHOLDING, COURTESY OF THE ROM (Click to Expand)

At the preview last week, visitors had the chance to see Acutiramus macrophthalmus in person. The fossil is the world’s largest specimen of its kind. It’s not evident from its large size, but the 420-million-year-old specimen is a distant relative to horseshoe crabs.

PHOTO COURTESY OF THE ROM (Click to Expand)

A 370-million-year-old Eusthenopteron fish and a Xenasaphus devexus trilobite are examples of some of the other fossils that will be featured.

SRIVINDHYA KOLLURU/THE VARSITY (Click to Expand)

 

PHOTO BY BRIAN BOYLE, COURTESY OF THE ROM (Click to Expand)

Construction of the Dawn of Life is slated to begin in 2019 and the ROM hopes to open the exhibit in 2021. Meanwhile, a preview of the gallery is located on the second-floor rotunda.

Dinosaur teeth uncover evolutionary secrets

UTM paleontologists search the past to learn how mammalian teeth evolved

Dinosaur teeth uncover evolutionary secrets

UTM paleontologists, professor Robert Reisz and former PhD student Aaron LeBlanc, published studies in PLOS One and the Proceedings of the Royal Society B that shed light on the complex evolution of teeth.

In PLOS One, Reisz and co-authors published an article that discusses Changchunsaurus parvus from the ornithopod family of dinosaurs. Ornithopods are herbivorous dinosaurs. Based on fossil records, ornithopods used their beaks to rip plants from the ground and had muscles to chew through coarse vegetation.

Reisz and LeBlanc explored the importance of this species in understanding the evolution of dentition in dinosaurs and a newfound form of teeth replacement.

LeBlanc’s study in the Proceedings of the Royal Society B located points of evolutionary change in mammalian dentition and delved into how mammalian dentition has evolved over the last 300 million years.

Both studies examined the fossil record by sawing off thin slices of tissue from the desired region. These slices were then polished to create transparent samples. The resulting slice was then subjected to three-dimensional analysis and subsequent computer configuration.

Herbivorous ornithopods are often studied due to the myriad of dental innovations they developed to cope with their diet. C. parvus was specifically studied, as it precedes major innovations in dinosaur dentistry and was thought to possess an ancestral version of previously investigated structures.

The thin sections examined confirmed the function of some components of the dental network. However, they also exhibited a novel form of tooth replacement, which was essential in herbivores due to the extensive pressures of a plant-based diet.

Reisz’s study also solidified that C. parvus had the earliest known occurrence of wavy enamel. This type of enamel was previously disassociated with the ornithopod family and its discovery in C. parvus opens their phylogenetic relationships for discussion.

The results are significant. C. parvus appears at a pivotal point in the evolutionary history of the tooth and understanding its dentition better will lead to a more complete understanding of teeth in general.

LeBlanc’s study examined tooth complexity.

Researchers previously believed that mammals had the most complex form of teeth, while reptiles possessed a simpler version. This was a result of mammals having a ligamentous attachment mechanism for teeth compared to the reptilian teeth being fused directly to the jaw.

But through observing thin sections of therapsid — early reptiles — teeth, Reisz and LeBlanc observed ligamentous structures similar to mammals.

Further study of thin sections from a variety of organisms implied that teeth ligaments developed before the divergence of mammals from reptiles, and that the reptilian fused teeth arrangement is in fact due to calcification — the accumulation of solid calcium deposits — of teeth over time.

Insight into dental history allows for a more comprehensive understanding of our teeth, and the resulting development of new theories, techniques, and explanations in dentition.