The Plastic and Evolutionary Responses of Fish to Anthropogenic Stressors
Bibliographic record
Abstract
Ecosystems are being altered at unprecedented rates with little knowledge of the potential impacts on biodiversity. Two of the most pressing contemporary anthropogenic stressors are pollution and global warming. Species can respond to these stressors via dispersal, phenotypic plasticity, or evolutionary adaptation. Many species, especially aquatic organisms, experience ecological or physical barriers to dispersal and will therefore have to respond via phenotypic plasticity or evolutionary responses. I examined the responses of multiple traits associated with fitness in fish to pollution and increased temperature using a 2 × 2 common garden experimental design. I examined the effects of pollution on behaviour in a natural population of brown bullheads (Ameiurus nebulosus), and increased temperature on population demographics, life history traits, reproductive traits, and the immune response in experimental populations of guppies (Poecilia reticulata). The plastic responses to pollution were increased locomotion and decreased aggression and the plastic responses to increased temperature were decreased age at maturity, sperm length, sperm velocity, and sperm path linearity. These results are indicative of stress responses by the fish and could potentially decrease reproductive success and survival. Next, I measured reproductive output in experimental populations of guppies and found that, after many generations in elevated temperature, females produced fewer, smaller broods than control populations. However, I found no effect of temperature on census population size, survivorship, sex ratio, size-at-age, or the immune response, indicating that, despite the decreased reproductive output, guppies appear to cope with the increased temperature. Additionally, genetic diversity in the elevated temperature populations decreased more rapidly than control populations, and was equivalent to one quarter the effective population size relative to the controls. This latter result shows a clear signature of selection. Indeed, I found that sperm length displayed an evolutionary response in an estimated 2-3 generations. And in a natural population of bullheads, after an estimated 33 generations, I found an evolutionary response in locomotion and aggression. However, the reduced genetic diversity could lower the adaptive potential of populations to future stressors. I discuss these results in the context of the scope of organisms to rapidly respond to anthropogenic stressors.
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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 | 0.001 |
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".