Understanding Conflict in the Human Placenta

How can we reconcile the evolutionary problem of cooperation? What can social amoebae tell us about the origins of multicellularity?

In this episode, we talk to Joan Strassmann and David Queller, professors at Washington University in St. Louis, about the evolution of cooperation and conflict. From social insects to humans, we can find instances of individuals seemingly sacrificing fitness for the good of the group. But, truly altruistic behavior poses a problem for evolutionary biologists because it challenges the assumption that natural selection favors individuals over groups. We talk with Joan and David about their work with the social amoeba, Dictyostelium discoideum. This species is known for its remarkable developmental cycle: when there is no more to eat, the starving amoebae aggregate into a slug-like organism, which then forms a fruiting body that releases spores in hopes of dispersing to a better place. The problem, evolutionarily, is that only a fraction of the cells in the fruiting body get to live on through offspring. This facultative lifestyle and the ability to combine genetically different cells makes D. discoideum a prime study species for understanding how relatedness impacts cooperation and conflict and the possible origins of multicellular organisms.

Towards the end of the episode, we also talk about Joan’s new book Slow Birding: The Art and Science of Enjoying the Birds in Your Own Backyard.

Cover art: Keating Shahmehri. Find a transcript of this episode on ⁠our website⁠.