week 2- quantitative genetics

Question 2

What is evolution?

Answer 2

The gradual change in heritable phenotypes within a population over time.

Question 3

What are the key questions to determine if humans are still evolving?

Answer 3

• Is there variation in a particular trait in a population? * Is the trait heritable? * Does having this trait affect survival or reproduction?

Question 4

What does sexual selection refer to?

Answer 4

A special form of selection that arises from differences in the ability to find and mate with members of the opposite sex.

Question 5

What are the two types of sexual selection?

Answer 5

• Intrasexual selection * Intersexual selection

Question 6

Define heritability.

Answer 6

A measure of how much genetics play a role in differences between individuals for a given trait.

Question 7

What is the breeder’s equation?

Answer 7

R = h2 * S

Question 8

What does R represent in the breeder’s equation?

Answer 8

Response to selection.

Question 9

What is the definition of quantitative traits?

Answer 9

Traits affected by many genes, typically described in numbers and showing continuous expression.

Question 10

What is the formula for phenotypic value (P) of an individual?

Answer 10

P = G + E

Question 11

What is the significance of broad sense heritability (H2)?

Answer 11

Proportion of the phenotypic variance due to all genetic effects.

Question 12

What does narrow sense heritability (h2) measure?

Answer 12

Proportion of the phenotypic variance due to only additive effects.

Question 13

What is phenotypic plasticity?

Answer 13

The ability of one genotype to produce different phenotypes in response to different environmental conditions.

Question 14

What is the relationship between phenotypic variance (VP) and genetic/environmental variance?

Answer 14

VP = VG + VE

Question 15

True or False: Heritability is measured on an individual.

Answer 15

False.

Question 16

Fill in the blank: The relationship between phenotypic values and genotypic values is measured by _______.

Answer 16

[heritability]

Question 17

What is the effect of additive variance on selection?

Answer 17

It is important for selection and directly affects the response of traits.

Question 18

What is stabilizing selection?

Answer 18

Selection that results from two opposing sources of directional selection.

Question 19

What are the three forms of selection?

Answer 19

• Directional selection * Stabilizing selection * Disruptive selection

Question 20

What does the match-mismatch hypothesis relate to?

Answer 20

The impact of phenotypic plasticity on adaptation to environmental changes.

Question 21

What is the Baldwin effect?

Answer 21

The concept that adaptive plasticity can lead to genetic changes in traits over time.

Question 22

What is the significance of the Price Equation in quantitative genetics?

Answer 22

It relates to heritability and the dynamics of selection.

Question 23

Define developmental plasticity.

Answer 23

Phenotypes that are transformed by development, breaking the direct genotype-to-phenotype link.

Question 24

What is the relationship between genotype and phenotype in quantitative traits?

Answer 24

Many different combinations of alleles can produce similar phenotypes.

Question 25

What is the role of reaction norms in phenotypic plasticity?

Answer 25

They capture the responses of genotypes to different environmental conditions.

Question 26

What is the impact of environmental conditions on the response to selection?

Answer 26

It can vary with episodes of selection and environmental changes.

Question 27

What does the term 'fitness proxies' refer to?

Answer 27

Measures that indicate an individual's ability to survive and reproduce.

Question 28

What is the importance of assessing correlations among traits?

Answer 28

To understand how fitness is determined by interactions among several traits.

Question 29

What is the Baldwin effect?

Answer 29

Plasticity in traits, genetic variation in this plasticity, adaptive selection acting upon this variation, and plastic traits becoming canalised ## Footnote The Baldwin effect highlights the role of phenotypic plasticity in evolution.

Question 30

What role does phenotypic plasticity play in trait evolution?

Answer 30

It allows organisms to adaptively respond to environmental changes. ## Footnote This is particularly relevant in the context of changing ecological conditions.

Question 31

What is the match-mismatch hypothesis?

Answer 31

It relates to how phenotypic plasticity can affect the timing of ecological interactions, such as predator-prey dynamics. ## Footnote This hypothesis suggests that mismatches in timing can lead to population declines.

Question 32

Which study discusses the effect of climate change on bird competition?

Answer 32

J.M. Samplonius and C. Both (2019). Curr. Biol. 29. ## Footnote This research indicates how climate change may increase competition between bird species.

Question 33

Under what conditions does phenotypic plasticity evolve?

Answer 33

When populations are in variable environments, environments produce reliable cues, different phenotypes are favoured in different environments, and no single phenotype has high fitness across all environments. ## Footnote This emphasizes the adaptive significance of plasticity.

Question 34

What do reaction norms capture?

Answer 34

Phenotypic plasticity ## Footnote Reaction norms illustrate how a single genotype can produce different phenotypes in response to varying environmental conditions.

Question 35

How does phenotypic plasticity influence evolution?

Answer 35

It can buffer or facilitate evolution. ## Footnote This means it can either stabilize traits or allow for rapid changes in response to environmental pressures.

Question 36

What is fitness in an evolutionary context?

Answer 36

A measurable feature of alleles, genotypes, or traits of individuals that predicts their numerical representation in future generations. ## Footnote Fitness is essential for understanding evolutionary success.

Question 37

Is fitness a relative or absolute concept?

Answer 37

Relative ## Footnote Fitness is determined by an individual's success in producing more offspring compared to others.

Question 38

What are fitness components?

Answer 38

Variables that occur at different life stages to estimate fitness, such as survival and reproduction. ## Footnote These components are crucial for understanding an organism's overall fitness.

Question 39

What are fitness proxies?

Answer 39

Variables assumed to be correlated to fitness components. ## Footnote These proxies help estimate fitness but may not always accurately reflect total fitness.

Question 40

List some examples of fitness proxies.

Answer 40

* Body size (male-male competition) * Food intake rate (foraging ecology) * Timing of breeding (reproductive ecology) * Probability of winning a contest (contest behaviour) * Sexual trait expression (sexual selection) * Clutch size (sexual selection) * Lifetime reproductive success (sexual selection) ## Footnote These proxies can provide insight into an individual's reproductive success.

Question 41

What are good practices for using fitness proxies?

Answer 41

* Cover most of an individual’s life cycle * Compare several fitness proxies * Measure a single proxy numerous times * Recognize limitations and assumptions of the proxy used ## Footnote Following these practices ensures more reliable fitness estimates.

Question 42

What topics are covered in Week 2 of the course?

Answer 42

* Quantitative traits * Heritability and breeder’s equation * Different types and episodes of selection * Phenotypic plasticity * Fitness ## Footnote This syllabus provides a comprehensive overview of key concepts in quantitative genetics.

Question 43

What discussion topic is suggested for the canvas discussion board?

Answer 43

Whether the adaptationist programme is a deeply engrained habit of thinking among students of evolution. ## Footnote This discussion aims to explore perspectives on evolutionary theory.