Lecture 2 & 3:physical challenges of the environment. Animals geographic ranges usually correspond to biomes (limit to climates or vegetation), but sometimes it is also affected by other factors: Pronghorns have a broad temperature tolerance range but a narrow habitat range. Elf owls, gila woodpekers depends on cactus. Tigers can live in any habitat either hot or cold. Radiation: emission of electromagnetic energy by a warm surface. Conduction: transfer of the kinetic energy of heat between substances in contact with one another. Convection: transfer of heat by the movement of liquids and gases. Redistribution: circulatory system redistributes heat among body parts. Larger organisms tend to lose heat across their surfaces less rapidly than smaller individuals this is because the surface-to-volume ratio is smaller(v sa ). It is easier for them to maintain a constant internal environment in the face of varying external conditions. Bergmann"s rule: homeotherms tend to be larger at a higher altitude.