Big Biology

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.

What 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.

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How 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.

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Can 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.

Why 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.

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Why 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.

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What is the link between climate change, declining wildlife populations and conflict  between animals and humans? And how should scientists, governments and individuals manage declining populations of wildlife, especially when humans rely on them?

On this episode, we explore the interface of biology and resource management with Briana Abrahms, from the Department of Biology and the Center for Ecosystem Sentinels at the University of Washington. Climate change is increasingly forcing humans and animals into conflict, often with disastrous outcomes for all parties involved. Briana studies the causes of these conflicts and their links to serious human problems like forced labor, terrorism, piracy, and poaching.

We talk about collisions between whales and ships, conflict between ranchers and carnivores, and elephants running amok in India. We also talk about the illegal wildlife trade in Africa and about subsistence fishing, problems which in some places have been addressed by effective local governance. Finally, we talk about what governments, scientists, and regular people can do to help.

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Does our DNA matter for our life outcomes? Can and should we use it for better social policy? And why have these questions caused such a stir?

On this episode of Big Biology, we talk with Kathryn Paige Harden, a professor in the Department of Psychology at the University of Texas at Austin where she leads the Developmental Behavior Genetics lab. Paige is the author of a new book, The Genetic Lottery: Why DNA Matters for Social Equality. In the book, Paige advocates for using genetic information to better understand variation in our life outcomes such as how many years of school we complete and other complex social, economic and educational conditions. She thinks that genetics can be a tool to help create a more equitable society, but her ideas have both ardent supporters and vociferous critics. We delve into why her book has been so controversial, how human genetic data might be used constructively and ethically, and whether the incorporation of more explicit evolutionary thinking about what genes actually do might prevent future misunderstanding and maybe even the misuse of genetic data.

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What roles does plasticity play in evolution?  Where does novelty come from, and how does it become widespread in populations?

On this episode, we talk all things plasticity with David Pfennig, a professor at the University of North Carolina, and Nick Levis, a postdoc at Indiana University. Their research focuses on something they call plasticity-led evolution. Building on older ideas, David and Nick argue that novel environments release hidden, or cryptic, genetic variation in some individuals in a population, which in turn allow selection to act on trait variation that is only revealed as plasticity is induced.

We discuss these ideas using a fantastic real-world example: spadefoots. These burrowing amphibians have expanded into the American Southwest, and tadpoles of some species develop dramatically different morphologies depending on what’s available to eat in their early lives. If they eat pond scum, they tend to become placid omnivores, but if they eat meat, they become giant carnivores that devour other aquatic animals…and even each other.

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How did life on Earth get from its humble beginnings to the dazzling array of forms we see now and in the fossil record?

On this episode, we talk with paleontologist Henry Gee about his latest book, A (Very) Short History of Life on Earth. The book offers a kaleidoscopic tour through the roughly 4 billion year history of life on Earth in just 288 pages. Gee is a longtime editor at Nature, and a master writer and storyteller. He shares his approach to good writing and discusses why professional science writing is often so dull. We also touch on his favorite chapters in the short history of life on Earth, including why some species evolved such large body sizes.

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