An explanation of the process of human hearing, covering the structure and function of the outer, middle, and inner ears, with a focus on explaining how the hair cells of the cochlea transduce mechanical motion into electrical signals that are interpreted as sound. I also discuss the mechanisms of sound localisation, some of the causes of deafness, and briefly outline the workings of the cochlea implant. Recommended pre-listening is Episode 53: Sound and Music.
An introduction to the physics of protons and neutrons in the atomic nucleus, with a focus on explaining the different modes of radioactivity, alpha, beta, and gamma decay, as well as different ways of measuring radiation and some of its biological effects. I also discuss some applications of radioactivity in radiometric dating, radiotherapy, nuclear power, and nuclear weapons. I conclude by discussing a few popular misconceptions about radioactivity. Recommending prelistening is Episode 8: History of the Atom.
An introduction to the economic concepts of GDP (Gross Domestic Product) and unemployment, including a discussion of how these concepts are defined, how they are measured, their relevance to understanding economic activity, and some limitations of these concepts as they are currently employed. Recommended pre-listening is Episode 65: Inflation and Interest Rates.
An overview of the processes involved in the generation of energy in cells, including a discussion of the role of ATP in energy storage, glycolysis, the krebs cycle, oxidative phosphorylation, and ATP synthase. Recommended pre-listening is Episode 18: Biochemistry Basics.
A discussion of minerals, including their main properties such as crystal structure, habit, cleavage, lustre, and hardness, followed by a brief overview of some of the major mineral classes, with a focus on the various types of silicate minerals. I also discuss the rock cycle and the relationship between the three major types of rocks: igneous, sedimentary, and metamorphic.
Continuing on from the previous episode, I discuss the role of antibodies and antigens in mediating adaptive immunity, and follow with a discussion of the functions and roles of B-cells and T-cells. I conclude the episode with an overview of the many components of the immune system and a discussion of how they interact to protect the body from pathogens. Recommended prelistening is Episode 72: Introduction to the Immune System Part I.
An overview of the human immune system, beginning with some basic anatomy of the lymphatic system, and proceeding through a discussion of the distinction between the innate and adaptive immune systems, the role of skin and mucus membranes in providing barriers to pathogen entry, the inflammatory response, an overview of the different types of leukocytes, and an initial foray into the workings of the complement system. Recommended pre-listening is Episode 10: The Cell.
A social scientific discussion and comparison of some of the major political ideologies in the world today, beginning with an overview of the origins, meaning, and limitations of the 'left-right' political spectrum, and continuing with an analysis of the historical origin and key beliefs of conservatism, liberalism, socialism, communism, anarchism, fascism, and other nationalist movements.
Continuing from Episode 69, I explore the diversity of the mammals, looking at all the mammalian orders and their major families. Special focus is given to primates and particularly hominids, which are discussed at the species level.
In this episode we explore the diversity of the animal kingdom. I first discuss the history of taxonomy and give an overview of some key concepts such as morphological similarity, phylogenetic analysis, systematics, cladistics, binomial classification, and the taxonomic hierarchy. Then follows an explanation of the diversity of and relationships between the major animal phyla, including arthropods, echinoderms, molluscs, and many others, with special emphasis is given to the classes and orders in the phylum of chordata (vertebrates).
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