L1 local adaptation 1

Question 1

What topics are introduced in the module overview?

Answer 1

Advanced topics in ecology and evolution, emphasizing relevance to ongoing research.

Question 2

How is the course structured?

Answer 2

24 lectures arranged into eight triplets, each triplet covering interconnected topics.

Question 3

What do individual lectures integrate?

Answer 3

General questions with research-specific case studies and examples.

Question 4

What is local adaptation?

Answer 4

Evolutionary outcome where resident genotypes have higher fitness in their local environment than non-resident genotypes.

Question 5

How is the ‘local environment’ defined?

Answer 5

The specific context or habitat in which organisms experience selection pressures.

Question 6

What distinguishes a ‘resident’ from a ‘non-resident’ individual?

Answer 6

Residents are native to the environment; non-residents come from other populations.

Question 7

How is local adaptation observed as a pattern?

Answer 7

By measurable fitness differences—often via reciprocal transplant experiments showing natives outperform foreigners.

Question 8

What key questions arise when viewing local adaptation as a pattern?

Answer 8

How much fitness difference is due to selection versus drift, and over what spatial scale it operates (e.g., migration/dispersal implications).

Question 9

How is local adaptation treated as a process?

Answer 9

As populations climbing an adaptive peak on a shifting fitness landscape, raising questions about rate, predictability, and mechanisms of divergence.

Question 10

Describe the design of a reciprocal transplant experiment.

Answer 10

Two populations are swapped between habitats; fitness is measured for each in both native and non-native settings.

Question 11

What does a ‘crossing’ performance curve indicate in a transplant graph?

Answer 11

Each population performs best in its home habitat, demonstrating spatial fitness variation.

Question 12

What caveat arises when one population has inbreeding depression?

Answer 12

Fitness differences may reflect inbreeding effects rather than true local adaptation, confounding results.

Question 13

Why might identical but isolated environments fail to show transplant fitness differences?

Answer 13

Ongoing adaptation may not produce measurable fitness differences, so pattern evidence may miss the process.

Question 14

What caution is needed when using space-for-time substitutions in experiments?

Answer 14

Interpretations must account for mismatches between observed patterns and the underlying adaptive processes.

Question 15

What is phenotypic plasticity?

Answer 15

A genotype’s ability to produce different phenotypes in response to environmental variation.

Question 16

How does adaptive plasticity differ from local adaptation?

Answer 16

Plasticity yields fitness benefits via flexibility; local adaptation arises from genetic differentiation among populations.

Question 17

Why is it essential to distinguish pattern from process in local adaptation studies?

Answer 17

To separate observable fitness differences from the evolutionary mechanisms driving them.

Question 18

Which modern techniques complement classical ecological methods for studying local adaptation?

Answer 18

Modern genomic approaches.

Question 19

What is phenotypic plasticity?

Answer 19

The capacity of a single genotype to produce different phenotypes in response to environmental conditions.

Question 20

Under what condition does a plastic genotype outperform a non-plastic one?

Answer 20

When the environment is variable, making flexible responses advantageous.

Question 21

What kind of temporal variability favors adaptive plasticity?

Answer 21

Short-term, unpredictable environmental changes experienced by future offspring.

Question 22

What spatial variability promotes the evolution of plasticity?

Answer 22

Micro-environmental differences where offspring disperse into conditions different from their parents’.

Question 23

Why is it difficult to differentiate plasticity from local adaptation?

Answer 23

Both can produce similar phenotypic patterns, requiring careful experimental design to disentangle them.

Question 24

What is a reaction norm plot?

Answer 24

A graph showing how different genotypes’ phenotypes change across an environmental gradient.

Question 25

How do non-plastic traits appear on a reaction norm plot?

Answer 25

As flat lines, indicating no phenotypic change with the environment.

Question 26

How do plastic traits without genotype×environment interaction appear?

Answer 26

As parallel, sloped lines where all genotypes change identically but differ in average phenotype.

Question 27

What pattern on a reaction norm plot indicates genotype×environment interaction?

Answer 27

Crossing lines, showing different genotypes respond differently to environmental change.

Question 28

How is narrow-sense heritability (h²) calculated?

Answer 28

As the ratio of genetic variance (VG) to total phenotypic variance (VP): h² = VG/VP.

Question 29

How do environmental effects and G×E interactions influence observed plasticity?

Answer 29

They add residual variance beyond VG, shaping reaction norms and overall phenotypic variance.

Question 30

What key distinction helps separate plasticity from local adaptation experimentally?

Answer 30

Local adaptation compares resident vs. non-resident populations in one environment; plasticity compares all genotypes across multiple environments.

Question 31

Describe the Caribbean lizard field experiment on morphology.

Answer 31

Lizards from larger islands were introduced to smaller islands with different vegetation; hind limb lengths were measured over generations via PCA.

Question 32

What morphological shift was observed in the Caribbean lizard field study?

Answer 32

Lizards on islands with thinner vegetation evolved shorter hind limbs, with change magnitude correlated to vegetation density.

Question 33

How did the laboratory perch-width experiment test plasticity in those lizards?

Answer 33

Lizards reared on narrow perches developed shorter hind limbs than those on wide perches, suggesting a plastic response.

Question 34

What conclusion was drawn from combining field and lab experiments on Caribbean lizards?

Answer 34

That breeding (common-garden) experiments are needed to confirm if limb differences are genetic or plastic.

Question 35

According to migration–selection balance, when does local adaptation occur?

Answer 35

When the strength of divergent selection exceeds the homogenizing effect of gene flow.

Question 36

In the continent–island model, what condition allows local adaptation on the island?

Answer 36

The selection coefficient (s) on the island must be greater than the migration rate (m) from the continent (s > m).

Question 37

What is the criterion for adaptation in the two-patch model?

Answer 37

The ratio of migration to selection must remain below one (m/s < 1) for each patch.

Question 38

Name two extensions to simple migration–selection models.

Answer 38

Incorporating patch‐size asymmetry and genetic drift in smaller populations.

Question 39

How can non-random gene flow reinforce local adaptation?

Answer 39

Environmental filtering causes migrants better suited to local conditions to succeed, strengthening adaptation.

Question 40

How does temporal variability affect local adaptation?

Answer 40

Fluctuating selection pressures over time can prevent populations from reaching any single local optimum.

Question 41

What is the cost of plasticity and how does it limit adaptation?

Answer 41

Energetic or developmental costs of producing alternative phenotypes can constrain both plastic and genetic responses.

Question 42

How can linkage disequilibrium facilitate coordinated local adaptation?

Answer 42

Tight linkage (e.g., chromosomal inversions) maintains co-adapted gene complexes against gene flow.

Question 43

What does expanding beyond abiotic adaptation involve?

Answer 43

Adapting not only to static physical factors but to environments that themselves evolve under selection.

Question 44

Give a classic example of host–parasite co-evolution.

Answer 44

Hosts and parasites evolve in tandem, with parasites often adapting faster in spatially variable interactions.

Question 45

How do plant–herbivore interactions illustrate co-evolution?

Answer 45

Both plants and herbivores evolve traits (e.g., defenses vs. feeding adaptations) in response to each other’s selective pressures.

Question 46

How do generation times affect co-evolutionary outcomes?

Answer 46

Faster-reproducing parties (e.g., parasites) adapt more rapidly, while similar generation times can lead to mutual local co-adaptation.

Question 47

Why is restricted gene flow important for local co-evolutionary differentiation?

Answer 47

High migration homogenizes gene pools, preventing spatially distinct evolutionary trajectories.

Question 48

What is the fundamental design of a reciprocal transplant experiment?

Answer 48

Moving individuals between two habitats and comparing transplanted versus native fitness in each.

Question 49

What experimental control is essential in transplant studies?

Answer 49

Applying identical handling or movement treatments to native and transplanted individuals to account for stress effects.

Question 50

What statistical result indicates genotype fitness depends on habitat?

Answer 50

A significant population×habitat interaction in performance metrics.

Question 51

What does a 'crossing' performance pattern signify?

Answer 51

Each population outperforms the other in its home habitat, a hallmark of local adaptation.

Question 52

How can both populations performing better in one habitat complicate interpretation?

Answer 52

It may reflect alternative processes (e.g., maternal effects, plasticity) rather than true local adaptation.

Question 53

Why is replication critical in local adaptation experiments?

Answer 53

Multiple replicates across patches ensure findings are generalizable, not artifacts of single trials.

Question 54

What makes certain habitat boundaries tractable for experiments?

Answer 54

Sharp contrasts (e.g., sea vs. freshwater) facilitate clear reciprocal transplants and interpretation.

Question 55

What broader implication ties genetic differences and plastic responses?

Answer 55

Rigorous designs must disentangle inherited adaptation from environmental responsiveness to avoid confounding.

Question 56

How can handling or movement effects bias fitness measurements?

Answer 56

Stress or injury from translocation can lower performance independent of genetic adaptation.

Question 57

What criteria must experiments meet to confirm true local adaptation?

Answer 57

Clear genotype×environment interactions, adequate controls, replication, and exclusion of non-adaptive factors.

Question 58

What role do visual and statistical frameworks play in assessing adaptation?

Answer 58

They help determine if fitness patterns reflect stable local adaptation or transient effects of mixing genotypes.

Question 59

What overarching challenge remains when studying local adaptation?

Answer 59

Differentiating genetic evolution from phenotypic plasticity and other confounding influences.