The gang celebrates four years of podcasting with a lengthy discussion about living fossils. What do we mean when we use the term living fossil, and can we come up with an operational definition? Also, Amanda risks invoking the destructive powers of John Wick, James invents the best Mass Effect slash fiction, and Curt plans for Amanda's replacement.

Musical track, "Sail the Canals" from Mario Party 7 is owned by Nintendo and Hudson. Used under fair use.

Up-goer Five (Amanda Edition): 

Today our friends talk about animals that lived a long time ago but still kind of are here today. People say that these animals that lived a long time ago are still here today and have not become any different than they were a long time ago. But our friends have a talk about how the animals that lived a long time ago and do not look different today are actually very different today than they were a very long time ago. Some of them might not look different but their stuff that makes them them is actually very different. Some of them have family that used to look very different even though they look like old, old animals that lived a long time ago. In the end, our friends decided that animals that look like animals that lived a long time ago are actually not the ones that lived a long time ago.

References:

Herrera‐Flores, Jorge A., Thomas L. Stubbs, and Michael J. Benton. "Macroevolutionary patterns in Rhynchocephalia: is the tuatara (Sphenodon punctatus) a living fossil?." Palaeontology (2017).

Kin, Adrian, and Błażej Błażejowski. "The horseshoe crab of the genus Limulus: living fossil or stabilomorph?." PLoS One 9.10 (2014): e108036.