Genetics and Reaction Norms Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary purpose of the reaction norm in genetics?

To track evolutionary changes in species

To model genetic mutations

To analyze phenotypic variations across populations

To serve as a theoretical tool for genetic studies (correct)

What concept did Schmalhausen replace 'organic selection' with?

Sexual selection

Directional selection

Natural selection

Stabilizing selection (correct)

What is the Baldwin Effect primarily associated with?

The introduction of new species

The interaction of phenotype and environment

The elimination of maladaptive traits

The integration of genetic mutations (correct)

Which statement best describes the adaptive norm of reaction?

It involves genetic mutations leading to stable phenotypic changes. Signup and view all the answers

What did Dobzhansky and Schmalhausen's work emphasize in evolutionary biology?

The importance of stabilizing selection for adaptive responses. Signup and view all the answers

What does the non-adaptive norm of reaction refer to?

Phenotypic changes that do not enhance fitness. Signup and view all the answers

What role does genetic mutation play in the adaptive norm of reaction according to the discussed theories?

They enable the phenotypic effect to be stabilized for future generations. Signup and view all the answers

Which publication is attributed to Waddington regarding modern genetics?

An Introduction to Modern Genetics Signup and view all the answers

What distinguishes adaptive phenotypic plasticity from non-adaptive plasticity?

It is genetically controlled. Signup and view all the answers

What role does non-adaptive plasticity play in relation to adaptive phenotypic plasticity?

It can favor the development of adaptive phenotypic plasticity. Signup and view all the answers

How is non-adaptive phenotypic plasticity characterized?

It is independent of genetic control. Signup and view all the answers

What controversy was addressed regarding the nature of plasticity?

Plasticity can be both a trait and an epiphenomenon of natural selection. Signup and view all the answers

What is the relationship between genetic control and non-adaptive plasticity?

Non-adaptive plasticity can express independently from genetic control. Signup and view all the answers

Which type of plasticity is influenced by natural selection?

Only adaptive phenotypic plasticity. Signup and view all the answers

What factor contributes to the variability of non-adaptive phenotypic plasticity?

Both genetic and environmental factors. Signup and view all the answers

Which describes the nature of plasticity as proposed by Sara Via?

It is a complex interaction of traits subject to change. Signup and view all the answers

What does West-Eberhard propose as the starting point for explaining traits' evolution?

Phenotypic variations Signup and view all the answers

What does Via argue regarding the independence between the trait mean and plasticity?

It remains to be confirmed. Signup and view all the answers

How does West-Eberhard define 'development'?

Any phenotypic change during an individual's life Signup and view all the answers

What is 'developmental plasticity' according to West-Eberhard?

The capacity to change in response to internal or external signals Signup and view all the answers

In the context of genetic variability, what does the term 'grand mean' refer to?

The average of a trait across multiple environments. Signup and view all the answers

Which of the following best describes the example of dwarf elephants?

Natural selection favored smaller elephants that could find food more easily. Signup and view all the answers

What is a characteristic of the approach mentioned in the content regarding plasticity?

It relies on observable types rather than real causes. Signup and view all the answers

Which model does the content suggest is not mutually exclusive?

Phenotypic plasticity. Signup and view all the answers

What does West-Eberhard consider to be a physical component in shaping an organism?

The genome Signup and view all the answers

What issue does Via raise about measuring the trait mean?

It can be determined for a single environment as well. Signup and view all the answers

Which statement regarding the 'phenotype' is accurate based on West-Eberhard's framework?

The phenotype is a result of both genetic and environmental interactions. Signup and view all the answers

What key factor influenced the development of the dwarf elephant trait?

Famine leading to atrophy Signup and view all the answers

What is often used to study models in quantitative genetics according to the content?

Statistical studies. Signup and view all the answers

Which term describes an organism's ability to change in response to stimuli?

Developmental plasticity Signup and view all the answers

What was the primary focus of the polynomial approach that Via's position rejected?

The independence of the trait mean from plasticity. Signup and view all the answers

What does the concept of environmental tolerance relate to?

The ability to adapt to external conditions. Signup and view all the answers

What is the main controversy surrounding genetic control for plasticity?

The definition of genetic control is still uncertain. Signup and view all the answers

According to Scheiner and Lyman, how many distinct categories correspond to the genetic bases of plasticity?

Three Signup and view all the answers

What does the term 'overdominance' describe in the context of genetic plasticity?

An inversely proportional relationship between heterozygosity and plasticity. Signup and view all the answers

What characteristic of phenotypic response does a homozygotic genotype exhibit according to the context?

Less plasticity in reaction norms. Signup and view all the answers

Which statement accurately reflects the current understanding of 'plasticity genes'?

They are associated with a polynomial relationship model. Signup and view all the answers

What did Scheiner and Lyman's assessment aim to establish regarding genetic expression?

The basis of genetic expression related to plasticity. Signup and view all the answers

What method did Scheiner and Lyman use to classify genetic bases of plasticity?

Systematic categorization. Signup and view all the answers

Why is the expression 'plasticity genes' considered plural?

It implies multiple genetic influences on plasticity. Signup and view all the answers

What is phenotypic plasticity described as in the context of changing environments?

An epiphenomenon resulting from the selection of different averages. Signup and view all the answers

According to Schlichting and Pigliucci, what are 'plasticity genes' defined as?

Regulatory loci that control structural gene expression in relation to the environment. Signup and view all the answers

What do Schlichting and Pigliucci suggest about the relationship between plasticity genes and plasticity as a by-product of selection?

They can coexist and are not mutually exclusive. Signup and view all the answers

What example is cited as proof of the existence of plasticity genes?

Phytochromes coding for plant responses. Signup and view all the answers

What is a key issue in the controversy discussed by Via and other researchers?

The complexity of interaction between different environmental variables. Signup and view all the answers

What concept did Via maintain regarding phenotypic plasticity?

It’s not a specific trait, but influenced by averages. Signup and view all the answers

What did the researchers categorize their disagreements as?

Semantic wrangling rather than true problems. Signup and view all the answers

How do Via's ideas on phenotypic plasticity contribute to evolutionary discussions?

They complicate understanding by invoking multiple variables. Signup and view all the answers

Study Notes

Phenotypic Plasticity: From Microevolution to Macroevolution

Phenotypic plasticity is a common concept in life sciences.
The term has two meanings: active—the capacity to shape or form (e.g., egg cell development); and passive—susceptibility to multiple form expressions (e.g., phenotypic plasticity).
Darwin discussed plasticity in terms of external conditions affecting the expression of various traits.
Darwin did not attribute environmental change to direct causation of variation.
More and Cudworth connected "plastic nature" to the Aristotelian view of ontogenesis and structural forces in biological organization.
The Soviet school refined the concept with the "reaction norm".
The norm of reaction (Reaktionsnorm) describes the range of phenotypes a single genotype can express across varying environments.
Schmalhausen and Dobzhansky developed the "adaptive norm".
This norm describes the transformation of phenotypic response into a genotypic response, highlighting its inheritance.
Bradshaw proposed the idea of genetic control of phenotypic plasticity, arguing that plasticity is a specific genetic trait, not a characteristic of the entire genome, and that genetic control over a character is separate from the trait control mechanism.
Lande and Via established quantitative genetic models to study the evolution of phenotypic plasticity.
Lande and Via demonstrated natural selection operating on expressed traits within specific environments.
The evolution of adaptive reaction norms occurs via phenotypic traits.
Schlichting and Pigliucci proposed "plasticity genes" as regulatory loci in charge of environmental control over structural gene expression.
Pigliucci revised the concept of "plasticity genes" in 1996, describing them as regulatory loci directly responding to environmental stimuli.
West-Eberhard, in her "developmental plasticity hypothesis", linked morphological and behavioral plasticity and saw development as a key aspect of understanding speciation and macroevolutionary changes.
Phenotypic plasticity plays a key role in microevolution and macroevolution, including speciation, niche diversification, and adaptive evolutionary changes.
Macroevolution is the evolutionary change, or the formation of new species, above the species level.
Phenotypic plasticity is central to adaptive evolution, and the concept of genetic variation and its evolution are important for resolving ongoing questions in evolutionary biology.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your understanding of reaction norms in genetics, including concepts like adaptive and non-adaptive plasticity. This quiz covers significant contributions by key figures in evolutionary biology like Dobzhansky and Schmalhausen. Explore the implications of genetic mutations and the role of natural selection in phenotypic plasticity.