Palaeo After Dark

The gang discusses two papers that look at the impact of ecological interactions on the evolutionary history of groups. The first looks at potential competitive interactions that could control rabbit body size, and the second paper uses the fossil record to investigate potential clade interactions between two groups of bryozoans. Meanwhile, Curt researches in real time, Amanda gets to talk about a childhood favorite, and James makes future plans.


Up-Goer Five (Curt Edition):

Our friends talk about two papers that look at how animals trying to get food and sometimes fighting with each other can change how they live and grow and make more of themselves. The first paper looks at animals that jump and have hair and their name sounds just like hair. These things that sound like hair do not get really big in most cases, even though we know that they could get big if we try and make it happen. This paper looks for reasons why these "hairs" don't get very big. It turns out that "hairs" eat things that a lot of other animals that eat. And while there are a lot of other things in the paper here that help to build this idea, the big idea is that that how big these "hairs" get may be held back by the smallest of the other animals that eat their food. "Hairs" get about as big as the smallest of these other animals in a place.

The second paper looks at animals that grow on top of other things. There are two big groups of these animals, and when we look at how they grow, usually one group will grow over the other group. This means this one group is better at growing in a space and can push out the other group. In the past we used to have more of the group that gets pushed out, but over time we have more of the new group that is better at growing in a place. Some have thought maybe this means that what we see happening in small places may explain this larger change over time. But it is more than just that because it is not just one group going down and another going up. This paper uses a lot of number work to see how these two group may change each other. They find that it is more than just a simple one up one down thing. They find both groups change each other in a few ways. They also don't find that the things happening in the small spaces is causing these bigger changes. It could be because of the type of things we are looking at makes it harder to see these changes, but with what they have it looks like maybe this is not what is causing this change.



Tomiya, Susumu, and Lauren K. Miller. "Why aren't rabbits and hares larger?." Evolution 75.4 (2021): 847-860.

Lidgard, Scott, et al. "When fossil clades ‘compete’: local dominance, global diversification dynamics and causation." Proceedings of the Royal Society B 288.1959 (2021): 20211632.

Direct download: Podcast_223_-_Amanda_Loves_Watership_Down.mp3
Category:general -- posted at: 3:00am EDT

The gang discusses two papers that look at evolutionary changes in animal groups after the End Cretaceous Mass Extinction. The first paper looks at morphometric changes in shark teeth, and the second paper studies the evolutionary and biogeographic patterns of snakes. Meanwhile, Amanda “fixes” her audio, Curt goes biblical, and James is missing.


Up-Goer Five (Curt Edition):

Our friends talk about things that lived through a real bad time when a huge rock hit the big round place where we all live. The first paper looks at large angry animals that move through water and have pointed things in their mouths and soft bits where things have hard bits. We usually just find the hard pointed bits from the mouth because the rest of the body falls to bits when they die. So this looks at how these old hard bits change from before and after the big rock hit. What they found was that changes happened within groups, where some groups were hit hard and others were not. But if you look at all of the big angry animals, it looks like very little changes. The hard bits are doing things that look the same before and after the rock hit, but its different groups doing that.

The second paper looks at animals with no legs and looked at changes in where they live and how quickly they change over time. The paper finds that after the big rock hit, one group was able to move to a new place. This move seems to happen when they also start making more of themselves. It seems that, for this big group of animals with no legs, the big rock hitting may have helped this group. It seems like a new place opened up after the big rock and the group took over and did well. There are also changes that we see when it gets colder in the time way after the rock hit.



Klein, Catherine G., et al. "Evolution and dispersal of snakes across the Cretaceous-Paleogene mass extinction." Nature Communications 12.1 (2021): 1-9.

Bazzi, Mohamad, et al. "Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction." PLoS biology 19.8 (2021): e3001108.

Direct download: Podcast_222_-_Static_Hiss.mp3
Category:general -- posted at: 3:00am EDT