Big Biology

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comHow do animals construct tissues, organs, and limbs in the right places during development? How do some animals manage to regenerate missing body parts?On this episode of Big Biology, we talk with Michael Levin, a biologist at Tufts University who studies how electric fields inside animals guide cells during development and regeneration. His work shows that electric fields play fundamental roles in structuring body plans and, in some species, can even be inherited across generations.

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comHow do we properly study complex traits? How does organismal function relate to how organisms evolve?All animals use oxygen to convert sugars and other substrates into energy using a multi-step pathway called the oxygen cascade. This cascade involves many, many parts of the respiratory, circulatory, and metabolic systems, making it a complex trait. Complex traits pose at least two major challenges to biologists: how do such multifaceted systems operate effectively and how do they evolve in the first place. Where does selection act in such systems: on the whole thing, on individual parts, or on the genes that underpin the functions of parts?On this episode, we talk to Graham Scott, a physiologist from McMaster University who studies the oxygen cascade in mice living on mountaintops, extreme environments for such small organisms. We discuss the concept of symmorphosis, the function and evolution of the oxygen cascade, and several clever experiments involving rat marathons and mighty mountain mice.Cover art: Keating Shahmehri

What’s behind the infamous zombie ant story? How does a fungus take control of an insect? Are zombies common in nature? How do biologists study the phenomenon of adaptive manipulation?Interns RB Smith and Natasha Dhamrait hijack the Big Biology channel to explore their favorite biology horror story, zombie ants! In this Little Biology episode, they dive into the unfortunate fate of these fungus-controlled ants and discuss some of the complicated evolutionary questions surrounding adaptive manipulation.Written and presented by: Natasha Dhamrait and RB SmithCover art: Keating Shahmehri This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit bigbiology.substack.com/subscribe

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comWhat makes a mammal a mammal? How did mammals survive the KT event when dinosaurs mostly went extinct? And why did mammals become so dominant?When we think of the Cretaceous, or the Jurassic, we immediately think of dinosaurs. But mammals were there too! Although they weren’t the mammals you would recognize today. So what is it that makes a mammal a mammal?On this episode of Big Biology, we talk with Steve Brusatte, professor of Paleontology and Evolution at the University of Edinburgh. Steve is the author of a new book: The Rise and Reign of the Mammals, which charts the evolution of our own mammalian ancestors, from those living in the time of the dinosaurs, through mass extinctions, to the diversity of mammals that dominate Earth today. We also talk to Steve about some of the remarkable people behind the discoveries that comprise what we know today.In the last half of the show, we talk about Steve’s previous book: The Rise and Fall of the Dinosaurs, which caught the attention of Colin Trevorrow, director of Jurassic World.  Based on that book, Colin brought Steve on as the scientific advisor for the new film: Jurassic World Dominion. We chat with Steve about his role in the making of the film and what we can expect from the new dinos (spoiler: FEATHERS!)Cover art: Keating Shahmehri

Is there a constant battle between our immune system and pathogens? Does the fighting ever end? Does the immune system do more than just provide defense against pathogens? On this episode, Art and Marty talk to Fred Tauber, a professor emeritus of medicine and philosophy at Boston University, about how the immune system does more than just protect our bodies from pathogens. Fred has published a number of books on immunity and philosophy. In his most recent book, "Immunity: The Evolution of an Idea", he explores the ideas discussed in this episode in greater detail. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit bigbiology.substack.com/subscribe

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comWhat do plants, animals and even river systems have in common?Branching networks are a universal element of life on Earth. Networks of veins, roots, xylem, phloem, and nerves – they all have large components that branch, usually repeatedly, into smaller and smaller components. The networks transport energy, materials, and information throughout the bodies in which they occur.Our guest today, Van Savage, is a professor in the department of Ecology and Evolutionary Biology and the department of Biomathematics at UCLA. We chat with Van about universal features of branched networks. We discuss how these networks are space filling and how their evolved structures facilitate rapid and energy-efficient transport. We also discuss why networks are fractals – branching structures that are self-similar across scales. You’ve seen the fractal nature of networks if you’ve noticed similarities between branching patterns of rivulets on a muddy bank and river connections viewed from a jet at 20,000 feet. We also discuss how differences in networks among taxa arise from the materials they transport. At the end of the conversation, Van explains how network theory illuminates what we know about metabolic scaling and how understanding branching can improve everything from artificial hearts to urban planning.Cover art: Keating Shahmehri

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comHow does one of the most diverse groups on the planet, the ants, interact with the extremely diverse group of microbes that live on and inside them?On this episode, we talk to Corrie Moreau, a professor of entomology at Cornell University, about the diversity and influence of microbes in ants. For Corrie, these microbes are a sort of internal rainforest, whose presence directly impacts the lives of the ants who carry them. Many ant-microbe relationships have evolved over millions of years, resulting in specialized interactions – from fungus-farming in leaf cutter ants, to insect mind control by the Ophiocordyceps fungus, to distortion of insect reproduction by Wolbachia bacteria. We also chat with Corrie about science communication, and how making biology a welcoming and diverse place will inspire the next generation of researchers and promote greater trust in science by the public.Cover art: Keating Shahmehri

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comCan selection act on ecosystems, societies, or planets such that some persist and others disappear? Must such systems reproduce to evolve?On this episode of Big Biology, we talk to Tim Lenton, Director of the Global Systems Institute (@GSI_Exeter) and a Professor of Climate Change and Earth System Science at the University of Exeter. In his 2021 Trends in Ecology & Evolution paper “Survival of the Systems,” Tim outlined his idea that large, complex systems--such as grasslands, coral reefs, and even human economies--are subject to a kind of natural selection based on their ability to persist. Tim argues that systems better able to extract and recycle resources will spread across landscapes and outcompete other such systems.This episode is produced in collaboration with Trends in Ecology & Evolution (@Trends_Ecol_Evo). TREE, published by Cell Press, is a monthly review journal that contains polished, concise and readable Reviews and Opinions in all areas of ecology and evolutionary science. It aims to keep scientists informed of new developments and ideas across the full range of ecology and evolutionary biology--from the pure to the applied, and from the molecular to the global. Visit: http://www.cell.com/trends/ecology-evolution.

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comWhy shouldn’t we think of living things as machines? What is and what isn’t an organism?In this episode, we talk to Dan Nicholson, a philosopher and biologist from George Mason University about his new edited volume, "Everything Flows: Toward a Processual Philosophy of Biology". In it, he and colleagues argue that biological systems more resemble flames and tornadoes and other dynamically stable systems than clocks or other human-designed things. Dan thinks that life is better understood as flows of energy and matter, which means that trying to reduce biological things into smaller parts, a popular practice in biology known as reductionism, will ultimately fail because it misses the stream-like nature of life. In the show today, we discuss these ideas, what Dan calls a processual philosophy for biology, including what it means for evolution, medicine, and more.Cover art: Keating Shahmehri

This is a free preview of a paid episode. To hear more, visit bigbiology.substack.comWhy are tropical mountain passes ‘higher’ than temperate ones? Why do some organisms regulate their temperature better than others, and what effect does this have on evolution?On this episode, we talk with Martha Muñoz, a professor in Yale’s Department of Ecology and Evolutionary Biology. We frame the chat in terms of two big ideas in thermal physiology – Janzen’s hypothesis and the Bogert Effect. Dan Janzen famously predicted that tropical ectotherms, with their relatively narrow thermal performance curves, would have a harder time moving up and over cold mountain passes. For organisms that rely on the environment to regulate their body temperatures, mountain passes appear higher in the tropics. These effectively higher mountains should lead to greater isolation of local populations and potentially greater rates of speciation because dispersal becomes more difficult. Charles Bogert focused on interactions between behavior and thermal evolution in ectotherms. He suggested that species with better capacity for behavioral thermoregulation would evolve more slowly – because thermoregulation shields thermal traits from the brunt of strong selection. We talk with Martha about these two ideas, and about how her work on Anolis lizards illustrates them.Cover art: Keating Shahmehri