Bibliographic record
Abstract
Speciation, the process by which one species evolves into two or more, is a major focus of ongoing debate, particularly regarding the geographic context in which it occurs. Geographic models of speciation tend to fall into discrete categories, typically referred to as allopatric, parapatric and sympatric speciation, according to whether two groups evolve reproductive isolation while geographically isolated, differentiated but connected by gene flow, or completely co-occurring. Yet molecular studies indicate that full development of reproductive isolation can take very long compared with the timescale at which climatic oscillations occur, such that the geographic context of differentiating forms might change often during the long process to full species. Studies of genetic relationships across the ranges of organisms with low-dispersal distances have the potential to reveal these complex histories. In a particularly elegant example in this issue, Dufresnes et al. () use genetic variation and ecological niche modelling to show that a ring of populations of the eastern tree frog (Hyla orientalis) surrounding the Black Sea had a complex history of geographic differentiation. Alternating phases of geographic fragmentation and phases of gene flow between neighbouring populations have produced a pattern of gradual genetic change connecting the western, southern and eastern sides of the ring, with the northwestern and northeastern forms being most differentiated. In the north, a population in Crimea appears to have been produced through mixture of the two extreme forms. The overall genetic relationships are reminiscent of those found in ring species, which have been used as prime demonstrations of the process of speciation. The difference, however, is that the terminal forms appear to have mixed rather than be reproductively isolated, although more research is needed to infer whether there might be some reproductive isolation on the northern side of the ring.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".