Located in the mountain parks of British Columbia, the Burgess Shale provides some of the best information about the early evolution of complex life 540 to 485 million years ago. The basic body plans of most animals alive today, including vertebrates like ourselves can be traced back to this period.

Highlighting new discoveries, Dr. Jean-Bernard Caron from the Royal Ontario Museum discusses the discovery of the exciting new Marble Canyon site, located in Kootenay National Park, and the way it has greatly increased our understanding of the evolution of ancient life.

The body proportions of many animals change as they get larger or older. This can be easily seen in humans, where babies have much larger heads (relative to the rest of the body) than adults. These changes in proportions are often accomplished by different growth rates between body parts, a process called allometry. In the case of humans, the head grows slower than the rest of the body and it said to be negatively allometric. When a structure grows faster than the rest of the animal, such as the antlers of a deer, is called positive allometry. When the two features grow at equal rates (and as a result the proportions do not change) this is said to be isometry.

Understanding the growth dynamics of living animals is an important part of their biology. The same is true for extinct animals, but in these cases we can’t observe the animals as they grow, and can only infer growth rates by looking at patterns across multiple individual fossils. To further complicate things, most extinct animals are not known from vast numbers of fossils, and have a limited sample upon which to base analyses of relative growth. This research paper investigates allometry in fossil animals in two ways:

  • A review of other published studies was conducted to document the sample sizes used for studies of allometry, and then to compare these results between animals alive today, and those known only from fossils. The result, unsurprisingly, shows that analyses of fossils generally rely on fewer specimens (less information) than those based on living animals.
  • A dataset of skull measurements for the American alligator (Alligator mississippiensis), was evaluated for allometry, and then reevaluated using fewer and fewer specimens to test the effect of reducing the sample size. The result was that at small sample sizes, the correct allometric trend was rarely identified. This is called Type II Error and often happens when sample sizes are small.

When the data from the two different analyses are combined we see that the sample sizes normally used for studies of allometry for fossils (from the literature review), are in the same range of sample sizes that experience high amounts of Type II Error (from the Alligator study). Studies of allometry based on fossils need to ensure the sample sizes are large enough to avoid large amounts of Type II Error, which will alter the results. This work helps help to highlight the continuing role of museum collections in scientific research – without a large number of specimens available to researchers the conclusions that can be made are limited.

Read the paper here: https://peerj.com/articles/818/

Caleb Marshall Brown and Matthew J. Vavrek, “Small sample sizes in the study of ontogenetic allometry; implications for palaeobiology,” PeerJ (March 10, 2015).

The last part of the Devonian Period and the early part of Carboniferous Period – 380 to 330 million years ago – were important times in the evolution of backboned animals. The Devonian has sometimes been called “The Age of Fishes” as there were more types of fishes alive than at any other time in Earth’s history. The last part of the Devonian is when some fishes with “legs” started to move from shallow water onto land. These fishes were the distant ancestors of what would become amphibians, reptiles, and mammals in the hundreds of millions of years that would follow.

This Speaker Series session by the Museum’s own Curator of Dinosaurs, Dr. Donald Henderson, reviews the fossil record and our understanding of the early colonization of the land by back-boned animals.

Hope Johnson (1916-2010) was a remarkable amateur paleontologist, naturalist, historian, botanist, and artist. Darren Tanke, Senior Technician at the Royal Tyrrell Museum presents original research on her remarkable history.

The Royal Tyrrell Museum’s Speaker Series talks are free and held every Thursday from January to April 2015 at 11:00 a.m. in the Museum auditorium. Please visit the website for more information about upcoming speakers.

Speaker Series 2015:  “The Role of Beringia in the Global Dispersal of Modern Humans”

Beringia is a geographic area that surrounds the Bering Strait, Chukchi Sea, and Bering Sea, and includes parts of Russia and Alaska. It is most famous for being the location of an ancient land bridge that connected Asia with North America at various times during the Pleistocene ice ages.  Although modern humans occupied western Beringia before the beginning of the Last Glacial Maximum, as part of a broader colonization of northern Eurasia that began 50,000–45,000 years ago, they were forced into areas of isolation (refugia) in central Beringia at the onset of the Last Glacial Maximum some 30,000 years ago.

In his talk, Dr. Hoffecker discusses the “Beringian Standstill Hypothesis,” an idea that proposes that when climates warmed and coastal and interior ice sheets in North America retreated, the western hemisphere was rapidly settled by people that occupied these refugia, and who had been genetically isolated for thousands of years.

 

The Royal Tyrrell Museum’s Speaker Series talks are free and held every Thursday from January to April 2015 at 11:00 a.m. in the Museum auditorium. Please visit the website for more information about upcoming speakers.

Speaker Series 2015:  “The Warm Fuzzies: Mammals and Climate Change in the Eocene of North America”

The Eocene Epoch (~55.5 to 35 million years ago) encompasses a number of significant climatic events in addition to well-documented immigration and extinction events that played an integral part in determining the current distribution of mammals across North America. Fossils found on the American Plains and in the Cypress Hills Interprovincial Park areas play a key role in determining what happened during that time period.

In his presentation, Dr. Alexander Dutchak from the University of Calgary discusses some of the methods used to identify climatic and mammalian faunal variability in the rock record and how these geologic signatures relate to one another across central North America during the Eocene Epoch.

 

The Royal Tyrrell Museum’s Speaker Series talks are free and held every Thursday from January to April 2015 at 11:00 a.m. in the Museum auditorium. Please visit the website for more information about upcoming speakers.

Speaker Series 2015:  “A Year in the Life of the Royal Tyrrell Museum’s Palaeontology Lab”

With hundreds of fossils being collected every year in Alberta, the preparation laboratory of the Royal Tyrrell Museum is a busy place. As fossils are being cleaned and sent away for study or display, new discoveries constantly roll in through the doors, which mean a palaeontology technician’s work is never done.

In her presentation, Dr. Lorna O’Brien, technician with the Royal Tyrrell Museum, showcases some of the exciting fossils that have been prepared in the past year. From fossils discovered in bonebed excavations to those exposed by the 2013 floods, be ready to be amazed at the rich palaeontological resources in the Museum.

 

The Royal Tyrrell Museum’s Speaker Series talks are free and held every Thursday from January to April 2015 at 11:00 a.m. in the Museum auditorium. Please visit the website for more information about upcoming speakers.

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