Abrupt changes in defence and trophic morphology of the giant threespine stickleback (<i>Gasterosteus</i>sp.) following colonization of a vacant habitat
Bibliographic record
Abstract
To evaluate the first stages of adaptation and differentiation following colonization into a vacant and ecologically divergent habitat, 100 melanistic and low-plated adult threespine stickleback (Gasterosteus aculeatus) exhibiting gigantism in body size and robust spines were transferred in 1993 from a large dystrophic lake (Mayer Lake, Haida Gwaii, British Columbia, Canada) with a diverse vertebrate predator regime, into an adjacent fishless eutrophic pond with macroinvertebrate piscivores. Eight generations were examined as a test of multiple functional hypotheses on the morphological traits that differentiate lake and pond stickleback throughout their distribution. Measurements of 20 defence and trophic traits were made on 275 wild-caught fish collected from the source and transplant populations over multiple years. There have been significant reductions (males: females) in plate count (8%: 0.5%), lateral plate 2 frequency (46%: 17%), lateral plate 3 height (17%: 18%), pelvic spine length (12%: 6%), dorsal spine length (21%: 16%), gill raker number (5%: 1%), and gill raker length (37%: 43%), and an increase in gill raker spacing (+5%: 0%), jaw length (+5%: +4%), and eye diameter (+8%: +7%). These changes within eight generations represent one-third of the morphological differences observed between naturally established large lake and pond populations in these archipelago and are all in the direction predicted from the change in habitat. Field samples indicate strong selection in the colonists although lab-reared individuals implicate an additional role of plasticity for dorsal spine and gill raker lengths, which may contribute to the rapid adaptation into novel and highly divergent selective landscapes.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".