Microbes are awesome, says biologist Paula Welander. They have shaped Earth’s chemistry and its environment over billions of years, including oxygenating the planet to make it habitable for larger life forms. In turn, microbes have been shaped by that very same environment, evolving as the climate has evolved, she says. Welander now studies the lipid membranes of ancient microbes, which can endure for millions of years, to understand this evolution and where we might be headed in the future. Microbes are our connection to the ancient world, Welander tells host Russ Altman on this episode of Stanford Engineering’s The Future of Everything podcast. Have a question for Russ? Send it our way in writing or via voice memo, and it might be featured on an upcoming episode. Please introduce yourself, let us know where you're listening from, and share your question. You can send questions to thefutureofeverything@stanford.edu. Episode Reference Links: Stanford Profile: Paula V. Welander Connect With Us: Episode Transcripts >>> The Future of Everything Website Connect with Russ >>> Threads / Bluesky / Mastodon Connect with School of Engineering >>> Twitter/X / Instagram / LinkedIn / Facebook Chapters: (00:00:00) Introduction Russ Altman introduces guest Paula Welander, a professor of Earth Science at Stanford University. (00:04:06) Why Study Microbial Lipids Why lipids are essential for modern microbiology and Earth’s history. (00:05:19) Diversity of Microbial Membranes How bacteria and Archaea build different kinds of membranes. (00:07:15) Reconstructing Ancient Environments Using specific lipid biomarkers to understand the early planet. (00:09:20) Chemical Fossils vs. Organism Fossils Why microbes don’t leave traditional fossils—but their lipids do. (00:10:55) Lipids as Environmental Clues How certain lipids indicate the environments organisms lived in. (00:12:36) Archaea: A Distinct and Ancient Entity Archaea’s evolutionary importance and chemically distinct membranes. (00:15:43) The Lipid Divide Why eukaryotic membranes resemble bacterial, not Archaeal, membranes. (00:17:12) Tracing Membrane Evolution Recent breakthroughs in studying Archaeal lineages related to eukaryotes. (00:19:11) Lipid Preservation Over Time How archaeal lipids are especially reliable as long-term biomarkers. (00:20:58) Sterols as Biomarkers The role sterols, including cholesterol, play in lipid archeology. (00:23:14) Bacterial Cholesterol Discovery The discovery that a rare bacteria can synthesize sterol precursors. (00:25:02) Functional Roles of Bacterial Sterols The possible roles sterols may play in microbial membranes and cell function. (00:26:31) Archaea in the Human Gut The number and types of Archaea found in the human microbiome. (00:28:43) Archaea and Antibiotics Whether Archaea react similarly to bacteria when exposed to antibiotics. (00:29:46) Future In a Minute Rapid-fire Q&A: hope, research needs, and alternate career dreams. (00:31:43) Conclusion Connect With Us: Episode Transcripts >>> The Future of Everything Website Connect with Russ >>> Threads / Bluesky / Mastodon Connect with School of Engineering >>> Twitter/X / Instagram / LinkedIn / Facebook Hosted by Simplecast, an AdsWizz company.