Neil Shubin (2) - Denis Duboule (2025-2026)

Neil Shubin’s lecture is a masterclass in evolutionary biology, offering a nuanced perspective on the origin of walking. He systematically dismantles the oversimplified narrative that walking evolved solely as a response to terrestrial life, presenting compelling evidence from fossils and living fish that walking behaviors predate the land transition. The argument is well-structured, building on previous lectures and incorporating multiple lines of evidence: paleontology, comparative anatomy, and developmental genetics. Shubin’s emphasis on the role of environmental changes, particularly the evolution of plants and the creation of new habitats, is a refreshing and insightful addition to the discussion. He effectively communicates complex scientific concepts without oversimplifying, making the lecture accessible to a broad audience while maintaining scientific rigor. The sources cited are primarily his own research and that of his colleagues, which is appropriate given his expertise. The lecture’s strength lies in its ability to challenge conventional wisdom and encourage viewers to think critically about evolutionary transitions. The only minor weakness is that the lecture is part of a series, so some context from the first lecture is assumed, but this does not detract from its overall quality. The title accurately reflects the content, and the lecture delivers on its promise to explore the fish inside us.

The title is generic but the content matches the series on fish evolution; the specific topic is the origin of walking.

9/10

Lecture by a leading paleontologist, president-elect of the US National Academy of Sciences, based on peer-reviewed research and fossil evidence. High credibility and scientific rigor.

Markers derived by PSI from the transcript: the creator did not define chapters.

• 02:00Introduction: Neil Shubin is introduced as a guest professor and president-elect of the National Academy of Sciences.
• 05:00Review of first lecture: how fish evolved into tetrapods, using fossils like Tiktaalik.
• 10:00Main question: how did walking evolve? Shubin challenges simple dichotomies between water and land.
• 15:00Environmental context: evolution of plants and terrestrial ecosystems during the Devonian.
• 20:00New environments: shallow streams, mudflats, and the role of invertebrates as food sources.
• 25:00Predators in water: large fish and arthropods, making walking advantageous.
• 30:00No simple dichotomy: many fish can walk underwater, and intermediate environments exist.
• 35:00Anatomical evidence: fins and limbs share genetic and developmental similarities.
• 40:00Energetics: walking can be more efficient than swimming at slow speeds in certain conditions.
• 45:00Conclusion: walking evolved in water, and the transition to land was not a simple event.

• Collège de France - Nos ancêtres les poissons — Official page for the lecture series.
• Denis Duboule - Chaire Évolution du développement et des génomes — Chair of the host professor.
• Playlist of the lecture series — YouTube playlist containing all lectures.

• Shubin, N. (2008). Your Inner Fish — Book by the lecturer that popularizes the concept of fish inside us.

• www.college-de-france.fr
• www.fondation-cdf.fr
• fr.linkedin.com
• www.threads.net