THREE

Practice vocabulary flashcards covering organismal responses to environmental temperature, plant and animal adaptations, and energy allocation principles.

Potential Distribution

The full theoretical geographic range an organism could occupy along an environmental gradient, which is typically larger than its actual distribution due to limiting factors like competition, predation, and physiological stress.

Physiological Stress

A condition occurring when environmental factors cause an organism's cellular processes to operate below their optimum rate, lowering fitness through reduced growth and reproduction.

Acclimation

Reversible physiological or behavioral adjustments made by an organism in response to environmental stress that are not genetically encoded.

Adaptation

A long-term response to environmental stress occurring at the genetic level, characterized by an increase in the frequency of advantageous alleles within a population.

Ecotypes

Populations within a species that display true genetic adaptations to specific environmental differences and may potentially be on their way to speciation.

Principle of Allocation

The concept that organisms face evolutionary trade-offs and cannot be simultaneously adapted to all environmental conditions due to limited access to energy and chemical nutrients.

Stomates

Eye-shaped microscopic structures on leaves that open to facilitate evapotranspiration, allowing plants to cool their body temperatures through evaporative water loss.

Pubescence

Hair-like structures on plant surfaces that can insulate cold-climate plants, reduce water loss, or create silvery, highly reflective surfaces with high albedo to prevent radiative heat gain in desert plants.

Ectotherms

Organisms whose metabolic rate is directly tied to ambient environmental temperature, leading them to regulate body temperature primarily through behaviors such as basking, burrowing, and microhabitat selection.

Endotherms

Organisms that generate and retain metabolic heat to regulate their internal temperature, typically utilizing insulating layers of fur or feathers.

Thermoneutral Zone

The range of environmental temperatures within which an endotherm does not need to expend additional energy to heat up or cool down to maintain its body temperature.