Sun, 29 March 2020
The gang talks about two papers which look at the ecology of the Ediacaran. One paper uses trace fossils to infer how ecological systems change as we move from the Ediacaran to the Cambrian, and the second paper identifies some interesting features previously undocumented in Ediacaran fossils. Meanwhile, Curt has ideas about sponges, the internet destroys James’s comedic timing, and Amanda is happy to finally put those years of teaching physiology to good use.
Up-Goer Five (Curt Edition):
Our friends talk about the time just before we have a lot of dead things that can appear in rocks. The first paper looks at the tracks left behind by animals and other things as they change through time. In the time before when we have a lot of dead things in rocks, there are still tracks. As we study these tracks, it turns out that there are lots of changes in these tracks that we didn't know about. It turns out that tracks show life was doing lots of things that we didn't see because the dead things themselves didn't get into rocks. This means the big changes we see as soon as dead things appear in the rocks might have been happening earlier.
The next paper looks at a group of weird things that were around a lot before we had a lot of dead things in the rocks. These weird things are like sticks with bits on either side. There used to be lots of these stick things, and it turns out that these stick things had small lines that goes to each of these sticks. These lines are very small, which is why it was so hard to find them. The paper thinks that these lines might mean that all of these sticks are a repeat of the same stick over and over again. This is something that some things that make their own food from the sun do today, meaning that making more of themselves by repeating over and over again might be something that first happened a long time ago.
Liu, Alexander G., and Frances S. Dunn. "Filamentous Connections between Ediacaran Fronds." Current Biology (2020).
Laing, Brittany A., et al. "A protracted Ediacaran–Cambrian transition: an ichnologic ecospace analysis of the Fortunian in Newfoundland, Canada." Geological Magazine 156.9 (2019): 1623-1630.