Radiation – E emitted from a surface Conduction – kinetic E trans. By contact Convection – moving air/liquid (boundary) Evaporation – exchange of latent E Adaptations to the Physical Environment  II. Light III. Heat Exchange A. Pathways of Exchange

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms 1. Heat Budget An organisms heat budget is strongly tied to both metabolism (producing heat) and water balance

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms 1. Heat Budget 2. Body Size and SA/V ratio

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms 1. Heat Budget 2. Body Size and SA/V Ratio 3. Effects of Temperature Increase metabolism, increase production of metabolic waste Increase evaporation Increase water demand

Adaptations to the Physical Environment  II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations Concept of flux: The rate of exchange of energy or matter (water) is a function of: - SA/V - energy/matter concentration gradient - characteristics of the surface (covered by oils or hairs?) Cushion plants Cacti

White-tailed Deer - Bergmann’s Rule (1847) Bears Adaptations to the Physical Environment  II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural White-tailed Deer - Bergmann’s Rule (1847) Bears Larger (smaller SA/V ratio) as latitude increases

Bergmann’s Rule (1847) Allen’s Rule (1849) Adaptations to the Physical Environment  II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural Bergmann’s Rule (1847) Allen’s Rule (1849) Lower SA/V – ‘rounder’ and latitude increases

Humans: Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural Humans: PETER T. KATZMARZYK AND WILLIAM R. LEONARD. (1998) Climatic Influences on Human Body Size and Proportions: Ecological Adaptations and Secular Trends. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 106:483–503. Bergmann

Humans: Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural Humans: PETER T. KATZMARZYK AND WILLIAM R. LEONARD. (1998) Climatic Influences on Human Body Size and Proportions: Ecological Adaptations and Secular Trends. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 106:483–503. Allen

increase edge/SA ratios, and increase SA/V ratios - maximize the loss of absorbed heat energy   shade leaf - broad sun leaf - deeply cut; narrow

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural Hairs, spines, feathers… create boundary layer.

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural 2. Physiological Homeotherms Poikilotherms Constant temp Variable temps Mostly birds and mammals; some large fish (tuna) Hummingbirds, some mammals that go into torpor regularly Endothermy: Generate heat Ectothermy: Temperature is environmentally determined Some tropical species, deep sea species, some dinosaurs (‘gigantotherms’) Most fish, inverts, amphibians, reptiles

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural 2. Physiological Increase surface blood flow to dissipate heat

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural 2. Physiological Decrease metabolism to reduce gradient and rate of heat loss

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural 2. Physiological Counter-current exchange to maximize heat retention

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural 2. Physiological 3. Behavioral Bask

Adaptations to the Physical Environment II. Light III. Heat Exchange Pathways of Exchange Effects on Organisms Adaptations 1. Structural 2. Physiological 3. Behavioral migrate