Adaptations, Part 2: Adapting to variable conditions (Textbook Chapter 5)

Vocabulary flashcards covering key terms from the lecture on adaptations to variable environments, phenotypic plasticity, reaction norms, and related experimental approaches.

Adaptation

A heritable trait that maintains or increases an organism's fitness in a given environment.

Phenotypic plasticity

Ability of a single genotype to produce multiple phenotypes in response to environmental conditions; traits may be reversible and can include morphological, physiological, and/or behavioral changes.

Norm of reaction

The set of phenotypes expressed by a single genotype across a range of environmental conditions (e.g., temperature during development; grasshopper coloration).

Reaction norm

The graph/plot showing how a phenotype changes across an environmental gradient; indicates whether plasticity is present.

Acclimation

A form of plasticity where an individual’s phenotype changes rapidly and reversibly in response to an environmental stressor (e.g., different enzyme expression in cold- vs. warm-acclimated fish).

Common garden

An experiment in which individuals from multiple populations are raised in a common, controlled environment to isolate genetic factors from environmental effects.

Reciprocal transplant

An experiment where individuals from different populations are swapped between native and non-native environments to test local adaptation and plastic responses.

Dormancy

Physiological plasticity to slow down metabolism when conditions are unfavorable.

Isozymes

Different forms of enzymes expressed in response to environmental conditions (e.g., in cold- versus warm-acclimated organisms).

Optimal foraging theory

A model that predicts foraging decisions by balancing costs and benefits to maximize net energy intake.

Thermal performance curve

A curve showing the temperature at which an organism performs best and how performance changes with temperature; used to predict responses to climate warming.

Temporal variation

Changes in the environment over time; can be predictable or irregular/unpredictable.

Spatial variation

Variability in the environment across space; organisms experience different conditions depending on location or scale.

Trade-off

A compromise where improvement in one environment or trait reduces fitness in another; phenotypic trade-offs can drive selection for plasticity.

Environmental variation

The combination of spatial and temporal variation in environments that shapes selection on plasticity and traits.

Fixed genetic differences

Genetic differences among populations that remain constant across environments, leading to persistent trait differences.

Common garden experiments

See Norm of reaction: raising individuals from multiple populations in the same environment to identify genetic factors.

Reciprocal transplant experiments

See Reciprocal transplant: exchanging individuals between native and non-native environments to study local adaptation and plasticity.

Plasticity vs genetics (determining cause of variation)

Determining whether observed trait differences are due to genetic differences or phenotypic plasticity typically involves approaches like common gardens and reciprocal transplants.