Sun, 30 April 2017
In this episode, the gang discusses two papers that use modern decay experiments to determine how decay can affect our understanding of the evolution of two groups, Coleoidea and Graptolithina. Are there certain structures or behaviors that make these animals more or less likely to be preserved in the fossil record? Also, the gang faces the existential void, James offers a gift, and Amanda learns something interesting about the greatest animals on the planet.
Up-Goer Five (James Edition):
This time, the group talks about what happens to things after they die. They look at studies that took things that were not dead and made them dead (or found dead ones on ice at a shop) and then watched what happened to them as time went on. We can then use the brain facts that we get from seeing these things continue to be dead to figure out what we are seeing when we look at things that have been dead for a really long time and turned into rock. First, we look at things that live in the water and have many arms. One group is not found in rock although they should have been around a long time ago, and because of the brain facts we get from watching them be dead we can tell it is because they do not drop in the water once they are dead. The second study looks at things that building their own houses by being sick on themselves. There are lots of them in the past but now only one group is left. By killing some of the ones that are left to see how they die we can see why we only find the old houses in rock and not the animals themselves, and also if dark bits we see in the houses in the rock may in fact be those animals!
Clements, Thomas, et al. "Buoyancy mechanisms limit preservation of coleoid cephalopod soft tissues in Mesozoic Lagerstätten." Palaeontology 60.1 (2017): 1-14.
Beli, Elena, Stefano Piraino, and Christopher B. Cameron. "Fossilization processes of graptolites: insights from the experimental decay of Rhabdopleura sp.(Pterobranchia)." Palaeontology (2017).
Sun, 16 April 2017
In this episode, the gang decides to go back to some old papers they enjoy to discuss the concept of homology. What do we really mean when we say certain characteristics are shared due to evolutionary history? Also, for a brief minute in the second half, James was spontaneously possessed by demonic spirits that made him spout nonsense he doesn't actually believe. Unrelated to this, he also had a splitting migraine.
Up-goer Five (Amanda in a fever-based fugue state edition):
Today our friends talk about how things are the same because animals are brother and sister. This means that the brother and sister animals have parts that are the same because they have the same mother and father animals. But the way that brother and sister animals have the same parts can be because of different ways. People do not understand really what it means when we say that these brother and sister animals have the same parts. So our friends try to explain how these parts came to be and why.
Van Valen, Leigh M. "Homology and causes." Journal of Morphology 173.3 (1982): 305-312.
Wiley, E. O. "Homology, identity and transformation." Mesozoic fishes 4 (2008): 9-21.
Sun, 2 April 2017
The gang talks about two papers that detail the ecology and evolution of some early fishy vertebrates. Can we tell what early coelacanth fish might have eaten? What evolutionary changes occurred when early tetrapods started making their way onto land? Is there an evolutionary trend towards kawaii? All this and less will be discussed.
Oh, and James has made some interesting discoveries about The Legend of Zelda.
Up-Goer Five (James Edition):
The group looks at two papers that are to do with animals with no legs that live in water although in one of the papers one of the animals is trying to have legs. In the first paper we see a very old animal with no legs that lives in water that has family around today that are thought to be pretty much the same but actually may be doing different things. We see that this old thing with no legs was eating a type of animal that we do not get any more, which is interesting as we have no way of telling that anything else ate this animal. In the second paper we look at things with no legs that are starting to having legs. We see that their eyes are moving on top of their heads like big angry things with hard skin and big teeth in long faces that live in the water. At the same time the eyes are moving onto the top of the head they are also getting bigger, and it is shown that the animals would have been able to see better out of the water. This seems to be happening at the same time as them starting to change their not legs into legs. The most interesting thing is that when some of the animals that then have legs go back into the water their eyes get smaller but do not move back down the side of the head; they are stuck there even though they are no good there any more!
MacIver, Malcolm A., et al. "Massive increase in visual range preceded the origin of terrestrial vertebrates." Proceedings of the National Academy of Sciences 114.12 (2017): E2375-E2384.
Zatoń, Michał, et al. "The first direct evidence of a Late Devonian coelacanth fish feeding on conodont animals." The Science of Nature 104.3-4 (2017): 26.