# Paul Ehrlich
**Domain:** Population Biology / Conservation / Coevolution
**Doc Type:** Thinker Node
**Maturity:** Developed
## Definition
**Paul R. Ehrlich** is an American biologist associated with Stanford whose research includes population biology, conservation and butterfly ecology.
## Nexus Context
Ehrlich's long-running checkerspot work at Jasper Ridge made a local butterfly population a model system for population dynamics and conservation. His 1964 paper with [[wiki/Peter Raven|Peter Raven]] helped establish modern coevolutionary analysis.
[[articles/The Evolutionary Roots of Silicon Valley|The Evolutionary Roots of Silicon Valley]] draws two machine-intelligence lessons from this work: distributed persistence requires viable ecological connectivity, and reciprocal adaptation is a stronger frame for human-machine change than static tool use.
Ehrlich's broader public claims about population have also been controversial. This node does not import every claim from that work; it isolates the documented ecological and coevolutionary contributions relevant to the nexus.
## Sources / Provenance
- Stanford faculty profile: https://profiles.stanford.edu/paul-ehrlich
- Stanford Jasper Ridge checkerspot history: https://jrbp.stanford.edu/longterm-studies-bay-checkerspot-butterfly-and-feasibility-reintroduction
## See Also
[[wiki/Bay Checkerspot Butterfly|Bay Checkerspot Butterfly]], [[wiki/Metapopulation|Metapopulation]], [[wiki/Coevolution|Coevolution]]