Cognitive Scaffold

Preparing your thinking workspace

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MENTAL MODEL · M3480

Island Biogeography

Island Biogeography
TechnicalHigh supportEcology
Included
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Version 1.0.0 · Updated 2026-07-30

CORE DEFINITION

MacArthur and Wilson proposed that the number of species on an island depends on the balance between two processes: the immigration rate of new species (higher closer to the mainland) and the extinction rate of existing species (higher on smaller islands).

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

Flow and stock model. Used to analyze user retention in communities, apps, or companies. Total users = acquisition rate (immigration) vs. churn rate (extinction). If your "island area" (product value) is too small, no matter how fast you acquire new users, you won't retain them.

anchor

Anchor fast decisions

MacArthur and Wilson proposed that the number of species on an island is the balance between immigration rate (higher near mainland) and extinction rate (higher on small islands). Extended as a "flow-stock" model. The mechanism is "dynamic balance between acquisition and loss."

MINIMUM ACTION

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Source support: Explicit

  • link
    en.wikipedia.orghttps://en.wikipedia.org/wiki/Insular_biogeographyZH · Explicit
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