Palaeo After Dark

A group of fresh faced scientists have biweekly informal discussions about evolutionary biology and palaeontology... over beer.

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Podcast 164 - Rails and Snails


The gang talks about two papers that are interested in iterative evolution, the repeated evolution of the same or similar morphological characteristics within or among species. Specifically, they are focused on iterative evolution in species on islands. The first paper they discuss looks at how being flightless might have evolved multiple times on the same island within the same species of rails. The second paper looks at repeated changes in developmental timing associated with climatic changes on an island. Also, James is an expert, Curt comes up with the best new Blue Sky series for the USA network “Rails and Snails”, and Amanda changes the podcast’s format.   Up-Goer Five (Curt Edition): Our friends talks about two times that weird things happen when animals get on an piece of land that is surrounded on all sides by water. The first paper looks at small light flying things. When these flying things get onto a piece of land surrounded by water, they seem to stop flying. However, they find these remains of these light flying things on this one piece of land so they can see how the way these remains look change, because the way these remains look will tell us if these light flying things had decided to stop flying. The cool thing is that many different flying groups of this same flying thing landed on this pieces of land surrounded by water and all decided to stop flying on their own. So the story for these light flying things is that they land on this piece of land surrounded by water, they stop flying, and then they die from breathing water when the land goes under, and then when the land is above the water, they repeat. The second paper looks at how these things that sit there, have a rock around them, and pull food out of water change over time. What the paper finds is that these little things with a rock around them look very different when the water goes up and down. The paper says that this is because of changes in how these little animals with a rock around them grow up. Do they take longer to grow up, do they look more like grown ups or do they look more like babies? The changes they see in how these things grow up happen at the same time as changes in where the water is, as well as how hot or cold it is.   References: Hume, Julian P., and David Martill. "Repeated evolution of flightlessness in Dryolimnas rails (Aves: Rallidae) after extinction and recolonization on Aldabra." Zoological Journal of the Linnean Society (2019).   Hearty, Paul J., and Storrs L. Olson. "Environmental Stress and Iterative Paedomorphism in Shells of Poecilozonites (Gastropoda: Gastrodontidae) from Bermuda." Palaios 34.1 (2019): 32-42. 


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 09 June 2019  1h8m