On the Evolution of Feathers from an Aerodynamic and Constructional View Point1
Bibliographic record
Abstract
The evolution of birds and feathers are examined in terms of the aerodynamic constraints imposed by the arboreal and cursorial models of flight evolution. The cursorial origin of flight is associated with the putative coelurosaurian ancestry of birds. As presently known, coelurosaurs have a center of mass located in the pelvic region and an elongated pubis that is ventrally or anteriorly directed. Both of these characteristics make it difficult to postulate an origin of flight that would involve a gliding phase because the abdomen cannot be flattened into an aerodynamic shape. Moreover, the cursorial model must counteract gravity using the hindlimb and, thus, selection for the power requirement for lift-off would not focus on the forelimb. Therefore, if the hypothesis proposing a coelurosaurian ancestry of birds is to remain viable, it must be via an as yet undiscovered taxon that is compatible with the morphological and aerodynamic constraints imposed by flight evolution.The arboreal model, currently centers around non-dinosaurian taxa and is more parsimonious in that early archosaurs have short pubes that do not preclude an aerodynamic body profile. Moreover, the arboreal proavis uses gravity to create the airflow over the body surfaces and is, thus, energy efficient. Consideration of the initial aerodynamic roles of feathers and feather design are consistent with a precursory gliding phase. Whether avian ancestry lies among coelurosaur theropods or earlier archosaurs, we must remain mindful of the complex aerodynamic dictates of gliding and powered flight and avoid formalistic approaches that co-opt sister taxa, with their known body form, as functional ancestors.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.004 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".