Lecture 2: Species ranges and the physical challenges of the environment: heat
Chemical reacts within organisms (enzyme function) occur at optimum temperature and
osmotic conditions where fitness is maximized.
Two types of tolerance:
1) Ranges of tolerance
2) Geographical range: corresponds to biomes usually but not always e.g. behavioural
habitat selection, other organisms e.g. extirpation of wolves leading to coyote
expansion, generalist vs. specialist
Radiation - heat transfer by electromagnetic radiation
Conduction—direct contact with substrate (e.g., feet lose heat to ground)
Convection—heat transfer mediated by moving fluid (usually air or water)
Evaporation—efficient cooling from wet surfaces
Redistribution—circulatory system redistributes heat among body parts, esp. core to
Want high SA to volume area to get rid of heat.
Bergmann’s rule: homeotherms t