Episode 160: The Evolution of Animals

We conclude our series on the standard model with an introduction to gauge theory. We discuss how the requirement of local gauge invariance generates interaction terms in the Lagrangian, and introduce the U(1) x SU(2) x SU(3) group structure of the standard model. We also consider the problem of massive W and Z bosons, and how this was resolved by the introduction of the Higgs field and the mechanism of spontaneous symmetry breaking. Recommended pre-listening is Episode 163: The Standard Model of Particle Physics. If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon supporter. https://www.patreon.com/jamesfodor https://www.paypal.me/ScienceofEverything

An introduction to the particles and forces that constitute the standard model of particle physics. After some historical background, we introduce each of the three fundamental forces that comprise the standard model - electromagnetism, the strong nuclear force, and the weak nuclear force. We then compare and contrast the different types of particles these forces interact with, including the difference between fermions and bosons, and between quarks and leptons. We consider the types of interactions experienced by these particles and the three generations of matter. Recommended pre-listening is Episodes 158 & 159: Quantum Electrodynamics Parts 1 and 2. If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon supporter. https://www.patreon.com/jamesfodor https://www.paypal.me/ScienceofEverything

Beginning with primitive Cynodonts in the late Permian, we our evolutionary development through Mesozoic mammaliaforms, the divergence of monotremes from marsupials and placentals, and culiminating in the emergence of primates in the early Cenozoic. Along the way we discuss the emergence of important traits such as the mammalian ear and various primate adaptations for arboreal life. We then discuss the sequence of hominin species in the lead up to to humans, including Ardipithecus, Australopithecus, Homo erectus, and Neanderthals. We conclude with an analysis of the emergence of distinctive human traits, including bipedalism, encephalisation, and extensive tool use. Recommended pre-listening is Episode 161: Dinosaurs and Other Ancient Reptiles. If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon supporter. https://www.patreon.com/jamesfodor https://www.paypal.me/ScienceofEverything

A survey of extinct animal species from the Permian through the Cretaceous periods. We discuss important differences between anapsids, synapsids, and diapsids, and then review diverse species from all groups, including pelycosaurs, therapsids, parareptiles, euryapsids, pterosaurs, pseudosuchia, and dinosaurs. We also consider aspects including bipedal gait, endothermy, gigantism, and the cause of the end Cretaceous mass extinction. Recommended pre-listening is Episode 160: The Evolution of Animals. If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon supporter. https://www.patreon.com/jamesfodor https://www.paypal.me/ScienceofEverything

Continuing from quantum electrodynamics part 1, here we explore the mathematical machinery used to compute interactions between particles, including propagators, Feynman diagrams, cross sections. We then walk through a simple example calculation to illustrate how these tools are applied. I conclude with an introduction to the problem of divergent loop integrals and how these can be resolved using renormalisation. Recommended pre-listening is Episode 158: Quantum Electrodynamics Part 1. If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon supporter. https://www.patreon.com/jamesfodor https://www.paypal.me/ScienceofEverything