A Big Step for a Fish – The Evolution of Four-Legged Land Animals

Explore the fascinating evolution of four-legged land animals in this 51-minute lecture from the Royal Tyrrell Museum Speaker Series. Join Dr. Donald Henderson, Curator of Dinosaurs, as he delves into the origins of vertebrates and tetrapods. Discover why tetrapods were not the first creatures on land and examine the locations of early tetrapod and near-tetrapod fossil discoveries. Challenge old theories about fish evolving to escape drying ponds, and learn about significant species like Latimeria chalumnae, Tiktaalik roseae, and Ichthyostega. Investigate intriguing evidence such as Middle Devonian tracks found in Poland, and consider alternative viewpoints on the aquatic nature of early tetrapods. Gain a deeper understanding of the complex transition from fish to land-dwelling vertebrates in this comprehensive exploration of evolutionary history.

A big step for a fish - the evolution of four-legged land animals
1 What are vertebrates?
1 How do vertebrate numbers compare to other organisms?
Tetrapods were not the first on land
Where have early tetrapod and near-tetrapods fossils been found?
Old idea: tetrapods evolved when fish crawled out of drying ponds to find new ponds
Latimeria chalumnae - a living coelacanth
Tiktaalik roseae (2008)
Ichthyostega (East Greenland, 365 million years) hind limb
Middle Devonian tracks, Poland
An alternative view to current dogma: Ichthyostega and Acanthostega are secondarily aquatic tetrapods
When is a fish not a fish?