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The evolutionary origin and diversification of feathers.
1Department of Ecology and Evolutionary Biology, and Natural History Museum, University of Kansas, Lawrence, Kansas 66045, USA. prum@ku.edu
The Quarterly Review of Biology
|October 9, 2002
Summary
Feathers evolved in nonavian theropod dinosaurs before birds and flight, originating from developmental novelties in feather follicles. Primitive feather fossils support this developmental theory of feather evolution.
Area of Science:
- Paleontology
- Developmental Biology
- Evolutionary Biology
Background:
- Evolutionary origin of feathers faced conceptual hurdles and lacked fossil evidence.
- Previous theories struggled to explain feather development and diversification.
Purpose of the Study:
- To review conceptual problems in feather evolution theories.
- To present and discuss the developmental theory of feather origin.
- To analyze primitive feather fossils from nonavian theropod dinosaurs.
Main Methods:
- Review of existing feather evolution theories.
- Analysis of fossil evidence from coelurosaurian theropod dinosaurs.
- Comparison of fossil feather morphology with developmental theory predictions.
Main Results:
- Primitive and derived feathers evolved in nonavian theropods prior to birds and flight.
- Fossil feather morphologies align with the developmental theory's predictions.
- The aerodynamic theory of feather origins is falsified; other functions remain plausible.
Conclusions:
- Feathers originated through evolutionary novelties in follicle and feather germ development.
- Feathers diversified within nonavian theropods, not exclusively in early birds.
- Feathers evolved as tubular appendages, with modular development driving innovation.