Coping with Variation & Temperature Regulation

Vocabulary flashcards focusing on key terms, physiological adaptations, and thermoregulation strategies from the lecture.

Wood frog

An amphibian capable of surviving being frozen solid with no heart rate or breathing, thawing when environmental temperatures rise.

Ice nucleating proteins

Proteins that freeze at higher temperatures in extracellular spaces to safely direct ice crystal formation away from vital tissues.

Antifreeze proteins

A group of proteins that bind to and encase growing ice crystals to limit ice growth and prevent structural damage to cells.

Glycogen

Polysaccharide energy stores in muscles and the liver that are broken down into glucose to lower the freezing point of body fluids.

Physiological ecology

The study of how an organism's physiological processes interact with and are affected by environmental conditions such as changing temperatures.

Climate envelope

The full range of environmental and climatic conditions over which a specific organism or species can survive.

Acclimation

Short-term, reversible phenotypic adjustments made by an individual organism in response to environmental stress without changing its genotype.

Adaptation

A long-term, non-reversible genetic change in a population occurring over generations in response to environmental pressures.

Ecotype

A population within a species that is genetically adapted to a specific local environment, which can eventually lead to subspecies formation.

Dormancy

An overall physiological state of reduced metabolic activity used by organisms to survive harsh environmental conditions.

Torpor

A general state of reduced body temperature and lowered metabolic rate that organisms enter to conserve energy during environmental stress.

Hibernation

An extended, long-term state of winter dormancy lasting months, characterized by significantly lowered body temperature and reduced metabolic rate.

Daily torpor

A short-term, typically nightly drop in metabolic rate and body temperature used by small animals like bats and mice to survive cold conditions.

Estivation

A period of dormancy entered by organisms to survive extreme heat and dry conditions or drought.

Denaturing

The structural unfolding and loss of functional shape of an enzyme caused by high temperatures or other environmental stress.

Heat shock proteins

Chaperone proteins that assist in properly folding new proteins or stabilizing proteins that threaten to denature due to high heat.

Isozymes

Different structural variants of the same enzyme that allow an organism to maintain metabolic function across varying environmental temperatures.

Homeoviscous adaptation

The adjustment of saturated versus unsaturated fatty acid composition in cell membranes to maintain proper fluidity at different external temperatures.

Conduction

The direct transfer of thermal energy between two physical objects that are in direct physical contact with one another.

Convection

The transfer of heat between an organism and its surroundings driven by the movement of air or water across a surface.

Latent heat transfer

The exchange of heat energy associated with a phase change of liquid, such as evaporative cooling through transpiration.

Radiation

The absorption or emission of electromagnetic heat energy (such as solar or infrared heat) between an organism and its environment.

Pubescence

Hair-like structures on plant leaf surfaces that help reflect infrared radiation and regulate heat absorption.

Endotherm

An organism that relies primarily on internally generated metabolic heat to regulate and maintain its body temperature.

Ectotherm

An organism that relies primarily on external environmental sources of thermal energy to regulate its body temperature.

Poikilotherm

An organism whose internal body temperature varies widely alongside ambient environmental temperature changes.

Homeotherm

An organism that maintains a relatively constant internal body temperature despite fluctuations in the surrounding environment.

Heterotherm

An organism that can alternate between ectothermic and endothermic modes or vary its body temperature depending on time or circumstances.

Thermal neutral zone

The range of environmental temperatures over which an endotherm maintains its basal metabolic rate without expending extra energy for thermoregulation.

Lower critical temperature

The environmental temperature threshold below which an endotherm must increase its metabolic rate to generate additional metabolic heat.