Rethinking Phenotypic Plasticity
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Questions and Answers

What does plasticity in organisms refer to?

  • The fixed traits of a genotype
  • The ability to resist environmental changes
  • The inability to adapt to different environments
  • The variation in phenotypic properties in response to environmental factors (correct)

What primarily distinguishes active plasticity from passive plasticity?

  • Active plasticity is anticipatory and often integrated. (correct)
  • Active plasticity only involves behavioral changes.
  • Active plasticity is always reversible.
  • Active plasticity requires no environmental cues.

Why is it important to quantify and compare plasticity?

  • To establish definitive causal relationships between phenotypic traits
  • To investigate the influence of plasticity on fitness and its costs or benefits (correct)
  • To prove that plasticity is always advantageous for survival
  • To demonstrate that all genotypes respond similarly to environmental changes

What type of changes are associated with active plasticity?

<p>Responses to environmental cues that may modify developmental pathways. (A)</p> Signup and view all the answers

What can be inferred from a non-flat reaction norm?

<p>The genotype shows a plastic response in certain phenotypic dimensions (B)</p> Signup and view all the answers

Which example illustrates the concept of active plasticity?

<p>Wing-length polymorphism in certain insect species. (A)</p> Signup and view all the answers

What is a potential source of information about the costs or benefits of plasticity?

<p>Performance comparisons among different genotypes across various environments (A)</p> Signup and view all the answers

What does it mean that associations based on observational data do not reveal causation?

<p>Correlation in the data does not confirm that one factor causes another (C)</p> Signup and view all the answers

What does phenotypic flexibility encompass?

<p>Changes in behavioral traits as a result of learning or environmental factors. (B)</p> Signup and view all the answers

What is a characteristic commonly observed in active plasticity?

<p>Graded responses that vary in magnitude. (D)</p> Signup and view all the answers

How can one phenotype show varying plasticity depending on environmental factors?

<p>By responding differently to separate environmental gradients or changes (D)</p> Signup and view all the answers

What implication does the statement 'plasticity should not be correlated across phenotypic dimensions' have?

<p>Each phenotypic dimension may respond independently to environmental factors (A)</p> Signup and view all the answers

How are behavioral traits affected in active plasticity?

<p>They can be modified based on learning and environmental stimuli. (B)</p> Signup and view all the answers

In the context of active plasticity, what does activational plasticity refer to?

<p>Changes that occur due to learning experiences. (C)</p> Signup and view all the answers

What do changes along environmental gradients inform researchers about?

<p>They help identify factors promoting the evolution of induced phenotypic variation (C)</p> Signup and view all the answers

What is likely to happen despite the flexible nature of many behavioral traits?

<p>There is a tendency for consistency over time. (A)</p> Signup and view all the answers

What complicates the interpretation of manipulation studies?

<p>Potential for pleiotropy and epistasis (C)</p> Signup and view all the answers

What aspect did the study mentioned not aim to evaluate?

<p>Effects of plasticity on establishment (D)</p> Signup and view all the answers

What is one possible method for manipulating phenotypic expression?

<p>Hormonal treatments (C)</p> Signup and view all the answers

Why is it difficult to interpret results from phenotypic engineering?

<p>Hormones have multiple cascading and interacting effects (A)</p> Signup and view all the answers

What did Davidson et al. (2011) report regarding invasive plant species?

<p>They possess higher phenotypic plasticity (D)</p> Signup and view all the answers

What allows the testing of effects of plasticity according to the content?

<p>Composite measures of species plasticity (C)</p> Signup and view all the answers

What characteristic of buffering traits complicates the understanding of plasticity changes?

<p>Their potential to increase or decrease plasticity (A)</p> Signup and view all the answers

How does plasticity impact establishment and population persistence?

<p>There is no empirical study on its effects (B)</p> Signup and view all the answers

What is a potential downside of plasticity in evolutionary processes?

<p>It may decrease average fitness. (C)</p> Signup and view all the answers

What complicates demonstrating causal relationships in plasticity studies?

<p>The need for experimental manipulation. (B)</p> Signup and view all the answers

How might developmental plasticity benefit species in changing environments?

<p>By enhancing establishment success. (A)</p> Signup and view all the answers

What does the ability to express plasticity independently of genetic variation allow individuals to do?

<p>Avoid extinction risk. (B)</p> Signup and view all the answers

What method has been suggested to manipulate levels of plasticity?

<p>Genetic engineering or artificial selection. (C)</p> Signup and view all the answers

What was the focus of Forsman's meta-analysis?

<p>Experimental manipulation studies of plants and animals. (B)</p> Signup and view all the answers

What is a challenge in testing for the effects of plasticity in organisms?

<p>Focus on whole organisms rather than single traits. (D)</p> Signup and view all the answers

What outcome may result from plasticity-induced phenotypic variation?

<p>Increased invasiveness. (D)</p> Signup and view all the answers

What primarily affects the buffering effect of plasticity-induced phenotypic variation against environmental change?

<p>Labile or flexible traits (A)</p> Signup and view all the answers

What experimental design could be used to evaluate the buffering effect of plasticity?

<p>Split-brood design (D)</p> Signup and view all the answers

Which type of data has most evidence about behavioral flexibility been based on?

<p>Observational data (A)</p> Signup and view all the answers

What does a quantitative assessment of plasticity reveal about its role in adaptation to climate change?

<p>It promotes ecological success (A)</p> Signup and view all the answers

Which aspect must be considered to improve understanding of plasticity's evolutionary dynamics?

<p>Reliability of environmental cues (B)</p> Signup and view all the answers

What is the main goal of evaluating the effects of environmental conditions on sibling populations?

<p>To assess establishment success and population dynamics (A)</p> Signup and view all the answers

Which of the following statements is true regarding the capacity for plasticity?

<p>It may buffer against environmental change (A)</p> Signup and view all the answers

What is suggested about individuals with naturally high versus low plasticity?

<p>Their use in experiments is equally problematic. (D)</p> Signup and view all the answers

What should be avoided to prevent overestimating the importance of plasticity in ecological contexts?

<p>Identifying unreliable traits (D)</p> Signup and view all the answers

What potential consequence could arise if there is a significant time lag between environmental cues and the response?

<p>The population might face extinction before adaptation occurs. (D)</p> Signup and view all the answers

Why is it important to differentiate between capacity to express plasticity and interindividual phenotypic variation?

<p>They lead to different evolutionary outcomes. (A)</p> Signup and view all the answers

What aspect of plasticity is emphasized concerning environmental change?

<p>It depends on spatial and temporal scales of change. (D)</p> Signup and view all the answers

What is a likely consequence of irreversible developmental plasticity?

<p>Phenotypic variation may not be realized until later generations. (B)</p> Signup and view all the answers

According to the discussion, what is lacking in current research surrounding plasticity?

<p>Supportive evidence for predictions about ecological success. (B)</p> Signup and view all the answers

What is a possible cost associated with time lags in response to environmental cues?

<p>Delayed expression of beneficial phenotypes. (D)</p> Signup and view all the answers

What does plasticity reportedly promote in populations and species?

<p>Ecological and evolutionary success. (B)</p> Signup and view all the answers

Flashcards

Active Plasticity

Anticipatory, integrated changes to an organism's traits in response to environmental cues or signals, modifying developmental pathways and regulatory genes.

Passive Plasticity

A type of plasticity that is not anticipatory but reactive. The provided text does not offer a formal specific definition for this term

Phenotypic Flexibility

The ability of an organism to change its traits in response to environmental changes.

Environmental Cue

A signal that triggers a response in an organism.

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Wing-length Polymorphism

Variations in wing size within a species of insects.

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Inducible Phenotypic Response

A change in an organism's traits that is triggered, or induced, by an environmental signal.

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Behavioral Traits

Characteristics related to an organism's actions and behaviors.

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Metabolic Demand

The need for energy or resources by an organism to perform its life processes.

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Multicellular organism plasticity

Multicellular organisms have phenotypic properties that can change (adapt) in response to environmental factors. This change isn't consistent across all features or environments.

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Plasticity and Reaction Norms

A genotype's reaction to an environmental factor is called its reaction norm. Plasticity isn't always consistent across all properties of a phenotype or across all environmental changes.

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Plasticity and Fitness

Researchers need to understand if plasticity impacts an organism’s ability to survive and reproduce successfully (fitness).

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Fitness and Evolution

Fitness impacts both the path and speed of evolution towards a fitness peak, influenced by changing or unchanging environments.

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Observational Studies

These studies reveal patterns, generate hypotheses, and provide insights into evolutionary processes, but can't prove causation.

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Plasticity and Costs

Investigating if plasticity comes with disadvantages like energy expenditure or risk to an organism is important.

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Plasticity and Evolution

Plasticity can speed up evolutionary rate but may reduce average fitness.

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Correlation of traits

Plastic responses to the environment don't automatically appear similarly across all traits within an individual.

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Causation vs. Observation

Observing associations between traits and environments doesn't prove a direct cause-and-effect relationship.

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Developmental Plasticity

The ability of organisms to adjust their phenotype based on their environment during development.

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Plasticity and Environmental Gradients

Variations in plasticity across different environmental changes can indicate the drivers for the evolution of adaptive traits.

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Establishment Success

How well a species establishes itself in a new environment.

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Experimental Manipulation

The use of experiments to test for cause-and-effect relationships.

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Testing Plasticity

Comparisons between different genotypes or populations in varying environmental conditions could determine the implications of plasticity on fitness.

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Genetic Engineering

Experimentally altering the genome for research purposes.

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Meta-Analysis

Combining the results of several studies to conclude about a larger trend

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Epistasis

The interaction between genes where one gene masks or modifies the expression of another gene. It's like a domino effect where one gene's action influences the outcome of another.

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Pleiotropy

When a single gene influences multiple traits. It's like a Swiss army knife, one tool serving multiple purposes.

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Buffering Traits

Traits that help an organism cope with environmental changes and maintain stability. Like shock absorbers, they cushion the organism from stress.

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Hormonal Treatments

Manipulating an organism's phenotype by introducing or altering hormones. It's like a chemical switch affecting various bodily functions.

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Experimental Manipulation Studies

Scientific experiments that directly alter an organism's traits to study their impact on establishment success and population persistence. These studies are like controlled experiments in a lab, allowing researchers to isolate the effects of a specific trait.

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Invasive Species

Species introduced into an environment outside their native range, often causing harm to the ecosystem. They're like unwelcome guests who disrupt the party.

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Plasticity's Role in Evolution

The idea that plasticity can lead to evolutionary diversity and speciation by allowing populations to adapt to different environments.

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Challenges Studying Plasticity

It's hard to study plasticity because differences in plasticity between groups might be influenced by genetic variation, making it difficult to isolate the effects of plasticity.

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Population-level Consequences of Plasticity

The impact that the ability of individuals within a population to change their traits in response to environmental cues has on the population as a whole.

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Plasticity and Environmental Heterogeneity

The effectiveness of plasticity depends on the variability of the environment and how quickly changes occur relative to the organism's life cycle and ability to move.

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Time Lags and Plasticity

When there's a delay between environmental change and the manifestation of a plastic response, it can lead to problems, especially if the change is irreversible and the needed phenotype doesn't develop in time.

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Costs of Time Lags in Plasticity

The negative consequences of a delay between environmental change and the expression of a plastic response, particularly for irreversible developmental changes where the altered trait only appears in the next generation.

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Differentiating Variation in Plasticity

It's important to distinguish between the effects of variations in the ability to change phenotypes (plasticity) and the consequences of differences in the levels of phenotypic variation resulting from plasticity.

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Evidence for Plasticity's Evolutionary Significance

There appears to be a lack of clear evidence to support the claim that plasticity directly promotes the ecological and evolutionary success of populations and species.

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Buffering Effect of Plasticity

The ability of phenotypic variation due to plasticity to help a population cope with environmental change.

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Labile Traits

Traits that are easily modified or changed in response to environmental factors.

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Fine-grained Environment

An environment where changes in conditions are subtle and occur over small spatial scales.

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Split-brood Design

An experimental design where siblings are split into different groups, each exposed to different environmental conditions.

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Standing Phenotypic Variation

The existing variation in traits within a population at a given time.

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Population Dynamics

The study of how a population changes in size and structure over time.

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Persistence of Populations

The ability of a population to survive and persist over time.

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Study Notes

Rethinking Phenotypic Plasticity

  • Much research explores conditions favoring phenotypic plasticity (adjusting to environment) in individuals and genotypes.
  • The consequences of plasticity on population/species success are gaining increased interest.
  • Analyzing plasticity and genetic polymorphism together is crucial for a holistic understanding.
  • Distinguishing between interindividual phenotypic variation from plasticity vs. capacity for plasticity expression is important.

Introduction

  • The review focuses on "whole organism" plasticity, its impact on ecological success, and rigorous testing of predictions.
  • Phenotypic plasticity, ability of a genotype to produce different phenotypes in response to environment, is crucial to understanding biodiversity's evolution and maintenance.
  • Significant increase in plasticity research (growth from <10 to nearly 1300 papers from 1983 to 2013).
  • Key questions: Does plasticity promote/hinder evolution/speciation? Is it adaptive? What are its costs? Relative roles of plasticity versus genetic evolution? Ecological conditions that promote plasticity?
  • Plasticity affects individual, population, and species level

From Causes to Population-Level Consequences of Plasticity

  • Interindividual variation in plasticity influences population performance and success.
  • Phenotypically and genetically diverse populations have wider niches, enhanced productivity, and reduced extinction risk.
  • Consequences are sometimes similar, regardless of origin (genetic polymorphism, plasticity, etc.), but mechanisms may differ.

What is Plasticity?

  • Plasticity (defined diversely), includes intraindividual variations.
  • Pronounced phenotypic differences among cells in similar individual (ex. blood, nerve cells).
  • Plasticity's definition is the ability of a single genotype to show a range of phenotypes in response to environmental shifts.

Active vs. Passive Plasticity

  • Active plasticity: anticipatory phenotypic changes in response to environmental cues/signals, involves developmental pathway modification.
  • Magnitude of response isn't always proportional to the stimulus.
  • Passive plasticity: direct environmental influences causing phenotypic changes (e.g., stunted growth due to scarcity), not anticipatory.
  • Response magnitude is often proportional to environmental differences.

Developmental Plasticity vs. Phenotypic Flexibility

  • Developmental plasticity: irreversible phenotypic changes during development (structural features, morphology, etc.) .
  • Phenotypic flexibility: reversible changes in labile traits (physiology, life history, behavior) , often learned or responsive to cues.

Is Plasticity Distinct from Genetic Polymorphism?

  • Plasticity and genetic polymorphism are not equivalent.
  • Evolution of plasticity is not always correlated with genetic polymorphism.
  • Irreversible developmental plasticity differs from genetic determinism only by environmental dependence of phenotypic expression.

What is a "Trait"?

  • Traits can be challenging to classify, especially when considering intraindividual variations like the repeated growing and changing of antlers in a deer.
  • Organisms have integrated phenotypic complexity, so identifying a "trait" for all time is difficult.

Comparing Levels of Plasticity Among Individuals

  • Plasticity isn't always correlated across traits or environments in organisms; a genotype could show plasticity for one dimension while not another.
  • Environmental cues that lack predictable or consistent effects on some traits may result in no corresponding phenotypic response.

How to Test Hypotheses Regarding the Consequences of Plasticity

  • Measuring plasticity requires quantifying, comparing, and experimentally manipulating levels of plasticity across individuals.
  • Evaluating costs and benefits usually involves comparing performance in various populations/groups or under different conditions/stressors.

Population-Level Consequences of Plasticity (Revised)

  • Plasticity may help or hinder populations, depending on environmental predictability/consistency.
  • Distinction between plasticity capacity and interindividual phenotypic variability is key.

Conclusions and Future Directions

  • More recent attention to the diverse potential of plasticity.
  • Problems with observational case studies outweighing direct manipulation experiments.
  • Need for clarification in terminology.
  • Practical challenges in measuring and understanding the true impact on individual, population, and whole organism plasticity.
  • Using experimental approaches is difficult, especially since individual plasticity can be related to other traits.
  • Plasticity may promote or hamper ecological population success.
  • Need for more experimental manipulation to disentangle the roles of genetic and plasticity changes.

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Rethinking Phenotypic Plasticity PDF

Description

This review delves into the concept of phenotypic plasticity, or the ability of a genotype to adapt its traits in response to environmental conditions. It emphasizes the importance of studying both plasticity and genetic polymorphism to understand their implications for ecological success and biodiversity. Key questions regarding the role of plasticity in evolution and speciation are explored.

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