Central Themes of Animal Physiology I. Structure-Function II. Change III. Homeostasis IV. Conformity and Regulation

I. Factors That Influence Structure-Function A. Mechanical B. Electrical C. Thermal D. Body Size

Phenotypic plasticity

II. Change Adaptation (evolutionary) via natural selection promotes  survivability and reproduction via DNA propagation is the ultimate physical drive (survival) Acclimatization change in an individual response to a new or altered environment Acclimation similar to acclimatization changes are induced experimentally

III. Homeostasis The process by which an organism maintains the “constancy” of its internal environment. Disease = change in internal environment which exceeds normal parameters. Receptors (sensors)  Integrating center  Effector Set point Feedback: the coupling of the output of a process to the input.

III. Homeostasis Negative feedback: An action directly opposes (corrects) the variation. Positive feedback: Initial stimulus produces a response that further increases the magnitude of the stimulus. Antagonistic effectors: Increase in one effector’s activity is coupled with a decrease in another’s.

IV. Conformity and Regulation Conformers cannot control internal conditions in response to outside changes osmoconformers: internal fluids conform to external fluids sea stars oxyconformers: O2 consumption changes with external levels annelid worms

Regulators maintain internal conditions in response to external changes osmoregulators: maintain [ions] internally regardless of external fluids oxyregulators: steady consumption of O2 regardless of external changes crayfish, most mollusks, most vertebrates most “inverts” are conformers and most “verts” are regulators

IV. Conformity and Regulation Regulation is expensive, but has its advantages. Some animals are both conforming and regulating depending on the parameter.

Iguana body temperature