#acclimatization

Adaptation

Acclimation refers to:

Acclimation is commonly defined as a reversible physiological adjustment by an individual to one controlled environmental variable in the laboratory. For example, animals maintained at a new experimental temperature may alter enzyme expression, membrane lipid composition, metabolic rate, or thermal tolerance over days or weeks. Acclimatization usually refers to a comparable adjustment under natural conditions, where temperature, humidity, oxygen, and other variables may change together. Both processes occur within a lifetime and depend on phenotypic plasticity; neither requires a new mutation

Ref: Evolutionary Analysis, Herron & Freeman, 5th Ed., Ch. 10

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Adaptation

Which of the following is an example of acclimatization?

A fish transferred to a new aquarium may gradually alter ion transport, ventilation, metabolic rate, stress-hormone levels, and behaviour in response to changed temperature, salinity, oxygen, light, or water chemistry. Such within-lifetime, usually reversible adjustment exemplifies acclimatization when it occurs under ordinary environmental exposure; in strictly controlled experimental terminology it may be called acclimation. No generational genetic change is required. The evolution of lungs in amphibian ancestors, by contrast, involved heritable changes filtered by natural selection over man

Ref: Evolutionary Analysis, Herron & Freeman, 5th Ed., Ch. 10

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Adaptation

Acclimatization occurs:

Acclimatization takes place within an individual organism as its physiology or morphology adjusts to a changed natural environment. The response may require hours, days, or weeks, depending on the system. At high altitude, altered breathing begins quickly, while increased red-cell mass develops more slowly; seasonal mammals may change coat thickness or metabolic settings over months. These changes arise through gene regulation, hormonal signalling, tissue remodelling, and phenotypic plasticity, not through a shift in population allele frequencies. Natural selection operates across differential

Ref: Evolutionary Analysis, Herron & Freeman, 5th Ed., Ch. 10

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Adaptation

Which of the following is a *temporary* adjustment to a new environment?

Acclimatization is a reversible phenotypic adjustment made by an individual after exposure to a changed natural environment. Moving to high altitude, for example, lowers oxygen availability and triggers increased ventilation, erythropoietin release, red-cell production, and altered tissue oxygen use over days to weeks. These responses improve performance without changing the individual’s inherited DNA sequence, and many diminish after return to low altitude. Adaptation, in the evolutionary sense, is a heritable population trait shaped by natural selection over generations. Evolution includes c

Ref: Evolutionary Analysis, Herron & Freeman, 5th Ed., Ch. 10

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