---
title: "phyletic gradualism"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "phyletic gradualism"
aliases: []
first_seen: "2026-07-09T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["punctuated equilibrium","directional evolution (trait model)","Charles Darwin (gradualist orthodoxy)","fossil record"]
---


The pre-1972 orthodoxy that Eldredge and Gould's 1972 paper explicitly named itself against — "Punctuated equilibria: an alternative to phyletic gradualism." Gradualism holds that morphological change accumulates steadily and directionally within a lineage over its whole fossil range, rather than concentrating at speciation with long intervening stasis. The vault's quantitative-paleobiology cluster treats gradualism operationally as the "directional evolution" model in the paleoTS model set — the mode Hunt's surveys find is rare (~5–13% of fitted sequences), which is the empirical leg gradualism's rejection actually stands on.

## References
- [[claim-punctuated-equilibrium-derives-from-mayr-peripatric-speciation]] · [[claim-hunt-2007-directional-evolution-rare-stasis-and-random-walk-split-evenly]] · [[claim-hunt-2007-framed-directional-rarity-as-corroborating-punctuated-equilibrium]]
- Related hubs: [[entity-punctuated-equilibrium]] · [[entity-gene-hunt]]
- Captures: 2026-07-09-hop-mayr-peripatric-speciation, 2026-07-16-does-gene-hunts-2007-survey-of-250-fossil