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.
Sun, 15 March 2020
The gang discusses two papers that look at the human impact on the fossil record. The first paper runs multiple model studies to try and determine when hominines (the group that includes all of our ancestors) first began significantly impacting the biosphere. The second paper estimates what our future fossil record may look like by using the state of Michigan as a model system (much to Amanda’s delight). Meanwhile, Amanda attempts to train a cat, Curt and James invent the best machine, James has his mind blown, and everyone wonders what the “prepper layer” of the Anthropocene will look like in a few million years.
Up-Goer Five (Curt Edition):
Our friends talk about how people have changed the world. First, they talk about how big brains might have led to lost of animals dying. This first paper looks at how brains got larger in the great great great great parents of people over time. They run a lot of numbers in a computer in order to find out if the real big animals that died went away because of people or because of changes in the places where these animals live. They look at how big the brains of these people were, as well as how much rain fell and if there were trees. What they find is that, after running all the numbers, is that the best answer out of all the things they looked at was that these animals started to die when the brains of people got bigger. They think this could mean that the people with bigger brains started to take food from some of these big animals, and that made it harder for these big animals to stay living.
The second paper looks at what we will leave behind after people are gone in the rocks. It uses a state that looks like a hand (and which one of our friends really really likes) as a way to look into this. Turns out, people cover things in ground a lot more than would usually happen without people. But people only cover in ground a small number of animals, like people, dogs, cats, and animals that we use on places where we make food. This means that the rocks after we are gone will look very different from the rocks before us. These rocks will be filled with just a few things, and most of those things will probably be in the same position. Also, a lot of the animals will all be men and all will have died for the same reasons.
Faurby, Søren, et al. "Brain expansion in early hominins predicts carnivore extinctions in East Africa." Ecology Letters.
Plotnick, Roy E., and Karen A. Koy. "The Anthropocene Fossil Record of Terrestrial Mammals." Anthropocene (2019): 100233.
Direct download: Podcast_183_-_Nobody_Wins_The_Human_Impact_on_Our_Future_Fossil_Record.mp3
Category:general -- posted at: 3:00am EST
Sun, 1 March 2020
The gang celebrates their 7th anniversary by inflicting pain on themselves for your amusement by discussing a classic paper, Gould's "Paradox of the First Tier". They discuss the paper in its historical context, and also how our knowledge of mass extinctions has changed and evolved from this paper. Meanwhile, James comes up with unconventional ways to communicate, Amanda may need some more whiskey to get through this, and Curt is all smiles.
Up-Goer Five (Curt Edition):
Our friends have fun on the day that comes around every year which is when they first started doing this thing. They talk about a paper that is old but looking to the time ahead. This paper is interested in how things die, especially when a lot of things die. There are bad times in the past when lots of things have died all at once. This paper points out that these bad times might be really important. These bad times when lots of things die all at once might act to change the direction of how life is changing through time. Life might be changing in one way and doing just fine, but when one of these bad times happens the things that were doing well might do bad but the things that were doing bad might do really well. Our friends talk about how the ideas brought up in this old paper have changed over time.
Gould, Stephen Jay. "The paradox of the first tier: an agenda for paleobiology." Paleobiology 11.1 (1985): 2-12.