An introduction to the processes by which cells control which genes are expressed. We begin with an overview of why genetic regulation is necessary and the key stages where such regulation occurs, including key concepts such as transcription factors and DNA binding domains. We then discuss prokaryotic gene regulation, focusing on the lac operon in E. coli. We then expand the discussion to cover the various mechanisms of eukaryotic gene regulation, including chromatic remodelling,...

Here we survey of the causes and consequences of genetic mutation, including a discussion of mechanisms of endogenous and induced mutations, rates of mutation, types of single nucleotide mutations, and the phenotypic effects of mutation. We also discuss various mechanisms for detecting and repairing genetic mutations, including base excision repair, DNA mismatch repair, nucleotide excision repair, double strand break repair. We conclude with an examination of large-scale chromosomal changes,...

An introduction to classical Mendelian genetics, in which we discuss Mendel's experiments with peas and the laws of heredity that he discovered, including inheritance of one allele from each parent, the law of dominance, and the law of independent segregation. We then consider more complex cases of genetic inheritance, including sex-linked traits, incomplete dominance, codominance, and epistasis. The episode concludes with a discussion of quantitative traits determined by many genes,...

Continuing our series on General Relativity, we discuss the derivation of the Schwarzschild metric as a vacuum solution to Einstein's Field Equations, and analyse the physical meaning of this solution, including the properties of the singularity, event horizon, and effects of time dilation and length compression. We then consider how solutions like the Schwarzschild metric yield testable predictions such as gravitational lensing and graviational redshift, which serve as important evidence in...

Our climate change series concludes with a discussion of the various lines of evidence indicating that recent warming is the result of human-produced greenhouse gases, including greater warming at night, cooling of the stratosphere, and relative depletion of C14 in the atmosphere. We then consider the various expected impacts of climate change, including increased extreme weather events, acidification of the oceans, changes to crop yields, and affects on various ecosystems. We end with an...

An overview of climate models, beginning with a summary of the major types of models, and then a more detailed disussion of hte primitive equations and parameterised feedbacks that characterise the widely used Atmospheric General Circulation Models. We also discuss techniques for model validation and some evidence regarding the accuracy of various climate models. Recommended pre-listening is Episode 142: The Greenhouse Effect. If you enjoyed the podcast please consider supporting the show by...

A detailed discussion of the greenhouse effect and its impact on Earth's climate. We begin with a discussion of Earth’s energy budget, the various greenhouse gases and their interactions with longwave radiation, and a summary of major sources of greenhouse gas emisions. We then examine the mechanisms of the greenhouse effect in more detail using the idealised greenhouse model and radiative transfer models. We conclude with an analysis of the sensitivity of Earth's climate to changes in...

An overview of the natural mechanisms by which climate changes over time. Beginning with an introduction to the concepts of radiative forcing and climate sensitivity, we then discuss solar forcing, orbital changes, volcanic eruptions, and silicate weathering, covering how each process operates and the effects it has on Earth's climate over varying periods of time. Recommended pre-listening is Episode 140: A History of Earth's Climate. If you enjoyed the podcast please consider supporting the...

A journey through the history of Earth's changing climate, in which we explore how Earth's climate has fluctuated over the past billion years. After reviewing the various temperature proxies used to estimate past climactic conditions, we discuss the varying hothouse and icehouse periods of Earth's history, the onset of the Quarternay Ice Age, the current interglacial period, the anomoly of the Younger Dryas, the Medieval Warm Period and Little Ice Ages, and the rapid rise in temperatures...

In this special collaboration with I Know Dino podcast, we discuss the history and impact of dinosaurs in popular culture and media. We cover the history of the scientific study of dinosaurs and how their presentation in media has changed over time with new discoveries, and what aspects of their behaviour and appearance tend to be presented accuracy or inaccurately. We also discuss lesser-known aspects of understanding dinosaurs, such as how changes in the atmosphere and ecosystem would...

An introduction to cryptography, internet security, and cryptocurrency, beginning with an overview of RSA cryptography and covering the use of public and private keys and their incorporation into the Transport Layer Security protocol used for secure internet communications. We then examine the key features of cryptocurrencies, including the blockchain, proof of work consensus mechanism, the use of hash functions, and the role of crypto mining. We conclude with a discussion of some of the...

A discussion of the metabolic pathways involved in breaking down proteins, carbohydrates, and lipids into simple components, extracting their energy, and building back up into more complex components needed for bodily function. We cover glycolysis, the citric acid cycle, lipolysis, beta oxidation, amino acid deamination, gluconeogenesis, fatty acid synthesis, and amino acid synthesis. Our overall focus is on the central role of acetyl-CoA and how the different metabolic pathways interact and...

A journey through the digestive system, beginning with the mouth and progressing through the esophagus, stomach, small intestine, and large intestine, we consider the structure and function of all key components of the gastrointestinal tract and their roles in facilitating the metabolism of our food. We also discuss the contribution of accessory organs, including the liver, gall bladder, and pancreas. We conclude by considering a few myths about digestion. Recommended pre-listening is Episode...

An introduction to the conceptual and mathematical framework of Einstein's General Theory of Relativity. We begin by considering the key insight of gravity as a geometric phenomenon, and how the curvature of spacetime by matter explains the equality of inertial and gravitational mass. We then discuss the mathematics of general relativity, including geodesics, differential manifolds, covariant derivatives, the metric tensor, Christoffel symbols, the Riemann curvature tensor, the Ricci tensor,...

An introduction to the scientific study of emotion, including a discussion of the difficulties in defining emotions, discrete and dimensional methods of classifying emotions, the functional and representational roles of emotions, and an overview of major psychological theories of emotion, including the James-Lange and Cannon-Bard theories. We also examine the neurobiological basis of emotion, including the roles of the orbitofrontal cortex, the ventromedial prefrontal cortex, the cingulate...

An introduction to hormones and the endocrine system, including a discussion of the definition of hormones and their production, storage, release, and mechanisms of action. I also consider the mechanisms of control and regulation of hormone production, focusing on the role of the hippocampus and the pituitary gland. I conclude with an overview of major endocrine glands in the human body, including the gonads, adrenal glands, thyroid gland, and the thymus. Recommended pre-listening is Episode...

A journey through the complex network of regions controlling the human motor system, beginning with the spinal cord and its central pattern generators, and working up through the primary motor cortex, the premotor cortex, the posterior parietal cortex, the cerebellum, and the basal ganglia. I discuss the computational roles of each part of the motor control hierarchy, focusing on what functions are performed and what information is represented in each unique brain region. Overall I emphasise...

In this special episode I discuss various topics in evolution and genetics with Art Woods of the Big Biology Podcast. We begin by analysing various ideas associated with the extended evolutionary synthesis, including plasticity, epigentics, and niche construction, discussing the extent to which these ideas are a challenge or merely an addition to the mainstream understanding of evolution. We then consider several common misconceptions about genetics, including the idea of DNA as a blueprint...

A journey through the mechanisms of muscles and muscular contraction. I begin by outlining the key structural elements of muscle cells, including the sarcolemma, sarcoplasmic reticulum, the myofibrils and their myofilaments. I then explain the sliding filament mechanism of muscle contraction, and how it is governed by neural signals through the release of calcium. I conclude with a brief overview of the types of muscle contractions, the difference between fast twitch and slow twitch muscle...

A special interview from the Padverb Podcast, in which I discuss my research on language in the brain and thoughts on AI. The discussion covers topics such as backpropagation, how humans acquire language and concepts, how artificial neural networks differ from biological neural networks, and some thoughts on the future impact of artificial intelligence. Near the end of the conversation, we also discuss some of my work on exploring the causes of economic growth and development. Link to the...

I discuss the mysterious phenomenon of sleep, outlining the different stages of sleep, how the brain controls sleep and wakefulness, and the various theories for the functions of sleep. I also consider sleep in animals, the effects of sleep deprivation, and some major sleep disorders. Recommended pre-listening is Episode 38: Neurons and Synapses.   If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon...

I introduce the unique and diverse chemistry of the transition metal elements, also known as the d-block metals. I begin with an overview of transition metal properties and ores, and then discuss coordination complexes, ligands, denticity, chelation, coordination geometries, isomerism, and the difference between strong and weak field ligands. We then examine how crystal field theory can explain many properties of transition metals, including their unique colouration and magnetic properties....

Concluding our series on geographic landforms, here I discuss glaciers, including their global distribution, formation, movement, and various glacial formations such as moraines, drumlins, and fjords. I also examine the role of ice in shaping periglacial landscapes, including the effects of permafrost and other frost action processes. I conclude with a brief discussion of groundwater, aquifers, and the hydrological cycle. If you enjoyed the podcast please consider supporting the show by...

A discussion of the effect of wind on landscapes, focusing on deserts and coastlines. I outline the processes of eolian erosion, transportation, and deposition occurring in deserts, with particular focus on the formation and types of sand dunes. I also discuss other desert landforms, such as the desert pavement, mesas, and alluvial fans. I conclude with a look at coastal processes, including cliff erosion, emergent and submergent coastlines, and beach erosion processes. If you enjoyed the...