The ecological causes of evolution

Environmental change can simultaneously cause abiotic stress and alter biological communities, yet adaptation of natural populations to co-changing environmental factors is poorly understood. We studied adaptation to acid and predator stress in six moor frog (Rana arvalis) populations along an acidification gradient, where abundance of invertebrate predators increases with increasing acidity of R. arvalis breeding ponds. First, we quantified divergence among the populations in anti-predator traits (behaviour and morphology) at different rearing conditions in the laboratory (factorial combinations of acid or neutral pH and the presence or the absence of a caged predator). Second, we evaluated relative fitness (survival) of the populations by exposing tadpoles from the different rearing conditions to predation by free-ranging dragonfly larvae. We found that morphological defences (relative tail depth) as well as survival of tadpoles under predation increased with increasing pond acidity (under most experimental conditions). Tail depth and larval size mediated survival differences among populations, but the contribution of trait divergence to survival was strongly dependent on prior rearing conditions. Our results indicate that R. arvalis populations are adapted to the elevated predator pressure in acidified ponds and emphasize the importance of multifarious selection via both direct (here: pH) and indirect (here: predators) environmental changes.

show abstract

“…B 281: 20133266 (e.g. [10]) and partly explain the strong local adaptation found in amphibian metapopulations (e.g. [29,52,53]).…”

Section: (D) General Implications and Conclusionmentioning

confidence: 99%

“…While adaptation to a single stressor appears commonplace, simultaneous adaptation to multiple stressors may be prevented by ecological or genetic trade-offs [2,8,9] or facilitated by correlated evolution [4,6]. However, our understanding of adaptation to multiple selective agents in natural populations is still limited [6,10,11].…”

Section: Introductionmentioning

confidence: 99%

Multifarious selection through environmental change: acidity and predator-mediated adaptive divergence in the moor frog (Rana arvalis)

et al. 2014

View full text Add to dashboard Cite

show abstract

“…This finding implies that the higher variation in reproductive contribution in rural as compared to urban females was not a consequence of higher variation in female condition. Theory suggests that environmental heterogeneity, either spatially or temporally, should promote variation in reproductive performance among individuals and the intensity of natural selection on phenotype (Wade and Kalisz, 1990;Byers, 2005;Siepielski et al, 2009Siepielski et al, , 2011Siepielski et al, , 2013MacColl, 2011). Conversely, in more homogeneous or benign environments, we might expect reduced variation in the reproductive contributions of individuals and intensity of natural selection.…”

Section: Discussionmentioning

confidence: 99%

Reproductive Contributions of Cardinals Are Consistent with a Hypothesis of Relaxed Selection in Urban Landscapes

Rodewald

Arcese

2017

Front. Ecol. Evol.

View full text Add to dashboard Cite

Human activities are leading to rapid environmental change globally and may affect the eco-evolutionary dynamics of species inhabiting human-dominated landscapes. Theory suggests that increases in environmental heterogeneity should promote variation in reproductive performance among individuals. At the same time, we know that novel environments, such as our urbanizing study system, may represent more benign or predictable environments due to resource subsidies and ecological changes. We tested the hypothesis that reduced environmental heterogeneity and enhanced resource availability in cities relax selective pressures on birds by testing if urban females vary less than rural females in their demographic contributions to local populations. From 2004 to 2014, we monitored local population densities and annual reproductive output of 470 female Northern Cardinals (Cardinalis cardinalis) breeding at 14 forested sites distributed across a rural-to-urban landscape gradient in Ohio, USA. Reproductive contribution was measured as the difference between individual and site-averaged annual reproductive output across all nesting attempts, divided by the annual density at each site. We show that among-individual variation in reproductive contribution to the next year's population declined with increasing urbanization, despite similar variability in body condition across the rural-urban gradient. Thus, female cardinals that bred in urban habitats within our study area were more similar in their contribution to the next generation than rural breeders, where a pattern of winners and losers was more evident. Within-individual variation in annual reproductive contribution also declined with increasing urbanization, indicating that performance of females was also more consistent among years in urban than rural landscapes. These findings are consistent with the hypothesis that urbanized environments offer more homogeneous or predictable conditions that may buffer individuals from environmental heterogeneity and relax natural selection.

show abstract

“…In humans, experimental methods such as surgical intervention or selective breeding are unethical (Ruse 1979). As a result, many aspects of humans continue to be debated, such as the female orgasm, human language, or rape (Travis 2003;Lloyd 2005;Nielsen 2009;MacColl 2011). Adaptive studies of unique features are not impossible, as some have charged (see Durrant and Haig 2001).…”

Section: How To Study Adaptation: the Vital Complementarity Of Comparmentioning

confidence: 99%

How to Study Adaptation (and Why To Do It That Way)

Olson¹,

Arroyo-Santos²

2015

The Quarterly Review of Biology

View full text Add to dashboard Cite

Some adaptationist explanations are regarded as maximally solid and others fanciful just-so stories. Just-so stories are explanations based on very little evidence. Lack of evidence leads to circular-sounding reasoning: "this trait was shaped by selection in unseen ancestral populations and this selection must have occurred because the trait is present." Well-supported adaptationist explanations include evidence that is not only abundant but selected from comparative, populational, and optimality perspectives, the three adaptationist subdisciplines. Each subdiscipline obtains its broad relevance in evolutionary biology via assumptions that can only be tested with the methods of the other subdisciplines. However, even in the best-supported explanations, assumptions regarding variation, heritability, and fitness in unseen ancestral populations are always present. These assumptions are accepted given how well they would explain the data if they were true. This means that some degree of "circularity" is present in all evolutionary explanations. Evolutionary explanation corresponds not to a deductive structure, as biologists usually assert, but instead to ones such as abduction or induction. With these structures in mind, we show the way to a healthier view of "circularity" in evolutionary biology, and why integration across the comparative, populational, and optimality approaches is necessary.

show abstract

The ecological causes of evolution

Cited by 244 publications

References 88 publications

Multifarious selection through environmental change: acidity and predator-mediated adaptive divergence in the moor frog (Rana arvalis)

Multifarious selection through environmental change: acidity and predator-mediated adaptive divergence in the moor frog (Rana arvalis)

Reproductive Contributions of Cardinals Are Consistent with a Hypothesis of Relaxed Selection in Urban Landscapes

How to Study Adaptation (and Why To Do It That Way)

Contact Info

Product

Resources

About