Science (Audio)

Peter Godfrey-Smith, Professor of History and Philosophy of Science at the University of Sydney, explores the evolutionary roots of consciousness by surveying animal evolution and the emergence of felt experience in several lineages. He examines two central philosophical questions: how such experience might arise gradually, existing in partial forms, and whether it represents a single unified feature with variations or instead a cluster of distinct traits. Author of "Darwinian Populations and Natural Selection," and "Living on Earth: Forests, Corals, Consciousness and the Making of the World," Godfrey-Smith brings his expertise in philosophy of biology and mind to illuminate how consciousness may have emerged and why its origins remain a profound puzzle. Series: "UC Berkeley Graduate Lectures" [Humanities] [Science] [Show ID: 41065]

The sequencing of genomes from archaic humans, such as Neanderthals and Denisovans, has transformed our understanding of human evolutionary history. These ancient genomes reveal that modern humans did not evolve in isolation but interbred with now-extinct groups, leaving lasting genetic legacies. To date, genomic sequences from 31 archaic human individuals, including four sequenced to high coverage, have provided unprecedented insights into the population structure, social organization, and adaptation of this now-extinct lineages, allowing us to reconstruct our own evolutionary history and the mechanisms that led to modern human success. Diyendo Massilani of Yale University School of Medicine reviews nearly three decades of research on archaic human DNA and what we have learned about how these groups lived, as well as how admixture between different lineages may have contributed both to the extinction of archaic humans and the thriving of modern humans. Ultimately, ancient genomes show that the success of our species was not predetermined but forged through encounters, exchanges, and adaptations, and that the legacies of archaic humans live on in our biology today, continuing to influence what it means to be human. Series: "CARTA - Center for Academic Research and Training in Anthropogeny" [Science] [Show ID: 41193]

Alejandro Sánchez Alvarado, Ph.D., argues that real progress in understanding regeneration comes from studying whole organisms rather than cells grown under artificial conditions. Sánchez Alvarado shows how observations from intact animals reveal organizing rules that narrow laboratory systems can miss. He presents evidence that stem cells in a studied animal lack detectable junctions with neighboring cells and instead respond to signals that travel across tissues. Sánchez Alvarado links this communication to extracellular vesicles that carry RNA and to metabolic support involving creatine, highlighting how distant tissues influence repair. Using imaging and molecular analyses, he tracks how signals move through the body and how specific cell populations change state during recovery. Sánchez Alvarado concludes that broad, comparative research is essential for uncovering general principles that govern how adult tissues restore form and function. Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 40454]

Climate investor and philanthropist Tom Steyer, recipient of the 2025 Charles David Keeling Memorial Lecture, talks about the current and future state of energy. In a conversation with Scott Lewis of Voice of San Diego, Steyer argues that capitalism and policy must work together at scale, and highlights the marketplace rise of renewables like solar and EVs alongside challenges like slow fossil-plant retirement, grid constraints, and the need for longer-duration storage. He also discusses emerging options such as advanced geothermal and nuclear. The Keeling Memorial Lecure is given by a prominent member of the global change community able to speak on topics that reflect the legacy of Keeling's work. [Science] [Business] [Show ID: 41034]

The genome sequences of Neandertals and Denisovans have provided a wealth of new information about the origins, migrations, and interactions of ancient humans. These genomes have revealed that mixture between hominin groups was common: all modern humans outside Africa carry around 2% Neandertal DNA from a single major episode of Neandertal gene flow, while the ancestors of present-day Asians and Oceanians also met and mixed with multiple, genetically distinct Denisovan populations. Archaeological evidence suggests multiple dispersals of modern humans out of Africa, with early fossils identified in East and Southeast Asia over 50 thousand years ago. In contrast, genomic studies indicate that all present-day non-African populations descend primarily from a single dispersal after ~50 ka, though the migration routes of ancestral populations across Eurasia and Oceania remain unclear. Janet Kelso, professor at Max Planck Institute for Evolutionary Anthropology, shows how using the distribution of Neandertal and Denisovan ancestry in ancient and present-day modern humans can determine when, where and how often modern and archaic humans met and mixed. Series: "CARTA - Center for Academic Research and Training in Anthropogeny" [Science] [Show ID: 41192]

An in vivo brain organoid platform reveals how human neurons and glia interact across development, aging, and disease. Fred H. Gage, Ph.D., generates three dimensional organoids from induced pluripotent stem cells and examines their maturation, synapses, and network activity with two-photon imaging and single-cell profiling. Gage integrates human microglia and astrocytes to study immune signaling, injury responses, and support functions that shape circuit behavior. Transplantation enables vascularization, reduces cell death, and yields features consistent with a blood brain barrier. Analyses identify diverse astrocyte types and trajectories, while patterns of tau expression inform Alzheimer’s disease modeling. Gage also converts adult fibroblasts into age retaining neurons that assemble into 3D spheroids, creating complementary models to connect genes, cells, and circuits with pathology and to guide strategies for prevention and therapy. Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 41160]

It is well known that inside nearly every living cell on this planet, there are instructions powering the dynamics of everything in the cell, known as deoxyribonucleic acid (DNA). Enoch Yeung, Associate Professor of Mechanical Engineering at UC, Santa Barbara, explains how DNA is the genetic code that tells cells where to live, how to live, and how to adapt when things get tough. Editing DNA has unlocked new potential in biology, enabled new therapeutics, diagnostics, and modes of treating diseases. Since DNA is double-stranded, it literally maintains a backup copy of itself to proof-read and facilitate stability of code. The double-stranded nature of DNA also means it can sometimes encode two messages in a given length! In short, DNA is amazing. Series: "GRIT Talks" [Science] [Show ID: 41040]

Clinical trials turn scientific discoveries into real options for patients and volunteers, advancing care while safeguarding participants. Sheldon Morris, M.D., M.P.H., explains how independent oversight, core ethical principles, and stepwise phases evaluate safety and benefit, and clarifies participants’ rights and responsibilities. Sandip Patel, M.D., F.A.S.C.O., highlights how carefully designed studies open access to promising cell and gene-based approaches while balancing risks and benefits. Robert A.J. Signer, Ph.D., underscores why participation—including consenting to share samples and data—helps researchers understand disease and accelerate better treatments. Morris, Patel, and Signer point audiences to practical ways to locate studies through registries and national databases, discuss what costs are typically covered, and advise asking questions about study design and safety. They also caution against unproven “stem cell tourism” and emphasize informed decisions. Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 40438]

Nature has been running chemistry experiments for over 4 billion years—yet today, much of modern organic chemistry still depends on wasteful, resource-heavy methods that rely on oil-based solvents. These solvents aren’t recycled, and when burned, they release CO2, adding to climate change. But what if chemistry could be done differently? Bruce Lipshutz, Distinguished Professor of Chemistry at UC Santa Barbara, shows how it’s possible to carry out organic reactions in water—nature’s own solvent. His research demonstrates that chemistry in water isn’t just more sustainable, it can also be faster, cheaper, and more effective than traditional approaches. Series: "GRIT Talks" [Science] [Show ID: 41029]

We’re surrounded by digital devices—from phones and tablets to streaming platforms and social media. With so many options at our fingertips, each of us faces choices about when and how to use technology in ways that align with our goals and values. In this talk, Kristy Hamilton, Assistant Professor in the Department of Communication at UCSB, shares research on how digital media shapes the way we see ourselves and, in turn, influences our everyday technology use. Hamilton uses experimental methods to study the strengths and challenges of human memory and cognition in digital environments, with the aim of helping people become more effective thinkers in today’s media landscape. Series: "GRIT Talks" [Science] [Show ID: 41030]