Ecological Phenotypic Plasticity Quiz

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Questions and Answers

What is expected to be very important in shaping phenotypic change in response to ecological change?

Environmental stability

Genetic drift

Phenotypic rigidity

Plasticity (correct)

Which scenario describes environmental conditions having a plastic effect without genetic differences?

Adaptive trait evolution

Flat reaction norms (correct)

Identical reaction norms (correct)

Genetic drift effects

What does it mean if environmental conditions had a genetic and plastic influence that reinforces each other?

Irreversible influence

Static influence

Counter-gradient influence

Cogradient influence (correct)

What might happen if environmental conditions influence plasticity that differs in direction between two groups?

Diverging slopes Signup and view all the answers

If plasticity is evolving on contemporary time scales, what does this imply?

Phenotypic changes reflect evolving plasticity Signup and view all the answers

What is the likely evolutionary origin of plasticity in a population?

Past selection processes Signup and view all the answers

Which of the following correctly represents groups that differ genetically in trait expression?

Non-flat reaction norms Signup and view all the answers

What is the implication of having counter-gradient influences in a trait's expression?

Genetic and plastic influences oppose each other Signup and view all the answers

What is a limitation of common analyses related to plasticity?

They often overlook genetic contributions to differences. Signup and view all the answers

Which of the following is an example of an adaptive plastic response?

Increased immune responses to parasites. Signup and view all the answers

What is highlighted as necessary to evaluate plasticity's adaptive significance?

Conducting experiments that monitor changes in fitness. Signup and view all the answers

What is one reason why not all plasticity is deemed adaptive?

Certain types of plasticity may lead to developmental problems. Signup and view all the answers

Which of these approaches aims to rule out genetic contributions to observed plasticity?

Partitioning approaches to understand variations. Signup and view all the answers

What kind of variation is noted in individual plasticity and adaptive significance?

Dramatic intra-specific variation. Signup and view all the answers

Which concept is important when analyzing temporal changes related to plasticity?

Considering factors beyond plasticity itself. Signup and view all the answers

What is a critical method for studying plasticity and fitness?

Conducting induced experiments and observing outcomes. Signup and view all the answers

What does a negative partial regression coefficient for plasticity suggest?

Selection against plasticity is indicated. Signup and view all the answers

What was observed in Trinidadian guppies regarding their plastic responses to predator cues?

They display greater plastic responses when not experiencing predator cues. Signup and view all the answers

In which environment did the study find that individuals differed dramatically in plasticity?

Netherlands Signup and view all the answers

What was the primary measure of plasticity in the studies of great tits?

Changes in breeding dates based on temperature. Signup and view all the answers

In the study by Gianoli and Gonzalez-Teuber, what trait showed plastic responses to simulated drought conditions?

Foliar trichome density Signup and view all the answers

What was the conclusion regarding the costs of canalization and costs of plasticity based on Van Buskirk and Steiner's meta-analysis?

Both costs are relatively weak and rarely significant. Signup and view all the answers

What does heterogeneity refer to in the context of the study on pond drying regimes?

The coefficient of variance in pool drying on an island. Signup and view all the answers

Which populations in the study showed the greatest plasticity?

Those experiencing drought stress with high temporal variation. Signup and view all the answers

What did the study in the UK population reveal about levels of plasticity?

Current levels of plasticity were not sufficient for adaptive responses. Signup and view all the answers

What is 'mean development time' as described in the context of frog offspring?

The time of offspring development under constant water levels. Signup and view all the answers

What type of regression model was used to analyze the data in these studies?

Lande and Arnold style multiple regression model Signup and view all the answers

What did the results from the Dutch population suggest regarding plasticity?

Increased plasticity was favored by selection. Signup and view all the answers

Which of the following statements is true regarding plasticity in frogs on Swedish islands?

Plasticity correlates with the variability of pond drying regimes. Signup and view all the answers

Why is the adaptive significance of plasticity confirmed for only one trait?

Only one trait showed consistent results across studies. Signup and view all the answers

How many studies and selection estimates were reviewed in the Van Buskirk and Steiner meta-analysis?

27 studies with 536 estimates Signup and view all the answers

What was the outcome of comparing three populations of Convolvulus chilensis?

The populations exhibited varied responses to environmental stress. Signup and view all the answers

What does the northern fish population do when raised in a common garden?

Grow faster and to a larger size than the southern population Signup and view all the answers

What do plastic effects on growth suggest about fish populations?

They lead to compensating genetic differences in growth rates Signup and view all the answers

How are brain size and invasion potential related in birds?

Larger residual brain size is linked to higher invasion potential Signup and view all the answers

What is suggested by contrasting patterns of co-gradient variation?

Plasticity has reduced genetic divergence Signup and view all the answers

What does the term 'cogradient genetic variation' imply in this context?

Plasticity aids in the evolution of genetic variation Signup and view all the answers

What do independent contrasts help control for in research?

Phylogenetic relationships Signup and view all the answers

What was noted about formal meta-analysis in this study?

No formal meta-analysis has been conducted Signup and view all the answers

What does residual brain size refer to?

Brain size adjusted for body size Signup and view all the answers

What is the main argument against plasticity promoting adaptive genetic change?

Plasticity shields the genotype from selection. Signup and view all the answers

What might maladaptive plasticity increase the selection for?

Adaptive genetic compensation. Signup and view all the answers

How does plasticity allow for colonization of extreme environments?

By allowing expression of cryptic genetic variation. Signup and view all the answers

What was observed in the experiment conducted by Schaum and Collins (2014)?

Lineages with more plasticity evolved faster growth rates. Signup and view all the answers

What kind of plasticity is mostly associated with slowing adaptive genetic change?

Maladaptive plasticity. Signup and view all the answers

What is one potential positive influence of plasticity mentioned?

It allows for expression of hidden traits. Signup and view all the answers

Which trait was examined in the Ostreococcus lineages study?

CO2-related plasticity. Signup and view all the answers

What is suggested as evidence that adaptive plasticity promotes genetic change?

Observations of faster adaptive evolution in certain traits. Signup and view all the answers

Study Notes

Key Questions on the Role of Phenotypic Plasticity in Eco-Evolutionary Dynamics

Phenotypic plasticity is the ability of an organism to change its phenotype in response to environmental changes, which can be influenced by genetics, phenotypic plasticity, or both
Plasticity can be adaptive, maladaptive, or neutral. Costs and limits of plasticity vary considerably, often being weak and difficult to detect.
Variable environments often favor the evolution of increased plasticity, which in turn can buffer fitness and support colonization of new habitats.
Phenotypic plasticity can sometimes aid or hinder ecological speciation, though more empirical studies are needed.

How to Infer Plasticity

Common approach involves experimental manipulations under controlled conditions, measuring the reaction norm (relationship between genotype and phenotype in different environments).
In species lacking inbred lines or clones, plasticity is estimated using related individuals (e.g., siblings) randomly sampled from different groups.
Different groups can display similar or different reaction norms, reflecting either inherent genetic differences or plasticity in response to environmental factors.

Evidence From Nature

Plasticity can be adaptive, maladaptive, or neutral, often posing a more nuanced question about the conditions promoting this most adaptive plasticity.
Whether plasticity has inherent costs or limits is often debated; results from meta-analyses reveal weak and variable costs.
Specific environmental (spatial variation, dispersal, etc.) and organismal (plasticity costs/limits, etc.) characteristics can impact the evolution of plasticity.

To What Extent Does Plasticity Aid Colonization and Responses to Environmental Change?

Phenotypic rescue, achieved through plasticity or genetic change, can help organisms persist and colonize new environments during environmental stressors.
The Baldwin Effect highlights how adaptive plasticity can direct subsequent genetic change in a similar direction, a phenomenon also known as genetic assimilation
Empirical evidence for plasticity’s importance in responding to environmental change is seen in some species exhibiting phenological shifts (e.g., breeding times) in response to climate warming.
Plasticity may sometimes be key for colonization and responses to environmental change, but may not always be necessary.

Does Plasticity Promote or Constrain Genetic Evolution?

Plasticity can potentially shield genotypes from selection, potentially slowing adaptive genetic change.
Conversely, plasticity can facilitate colonization/persistence in extreme environments, potentially increasing selection on other traits or exposing cryptic genetic variation.
Plasticity may influence genetic architecture so as to increase the production of adaptive phenotypes.
Counter-gradient variation, wherein genetic and plastic effects have opposing directions, implies that maladaptive plasticity can promote compensatory genetic change.

Does Plasticity Help or Hinder Ecological Speciation?

Plasticity can potentially promote speciation when similar in direction to genetic differences between species.
Polyphenism (generating different phenotypes in response to different environments) can facilitate character displacement and sharpen reproductive barriers.
Species that form more species may also show greater plasticity. However, plasticity can also potentially constrain speciation by shielding genotypes.
Imprinting on parents, conspecifics, environments, or resources can lead to assortative mating, thereby generating reproductive isolation, influenced, in part, by plasticity.

How Fast Does Plasticity Evolve?

Reaction norms can evolve over decades, exemplified by studies on Daphnia phototaxis in response to changing predation pressures.
Some species (e.g., Polygonum cespitosum, Hemigrapsus sanguineus) show evolved plasticity related to changing habitats, confirming the potential for rapid plasticity evolution.
Meta-analyses are crucial for establishing broader evolutionary plasticity rates.

How Might Plasticity Have Community/Ecosystem Effects?

Plasticity in organismal traits (e.g., foraging in fishes, biological stoichiometry in animals and plants) can influence community and ecosystem dynamics.
Plastic changes often have cascading effects on other communities and ecosystems, as seen in shifts of foraging traits or phenology.
Formal studies linking plasticity to community/ecosystem dynamics are currently rare, but this area warrants further investigation.

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Description

Test your understanding of phenotypic plasticity and its role in evolutionary responses to ecological changes. This quiz explores the genetic and environmental influences on trait expression, adaptive responses, and the limitations of current analyses. Perfect for biology students looking to deepen their knowledge in ecology and evolution.