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3. Along with precipitation amount, temperature is a strong determinant of biome distribution, and local scale adaptations.
Heat energy is expressed as temperature, which is quantification of molecular kinetic motion.
Homeothermy = maintain constant temperature in face of changing external temperature. Do so be combination of behavioral adaptations and endothermy = generates on heat by metabolism.
Poikilothermy = body temperature equilibrates with external temperature - the so called “cold blooded” organisms, including plants.
Organism tolerances of thermal extremes (-60 to +60°C)
Along with precipitation amount, temperature is a strong determinant of biome distribution, and local scale adaptations.
Heat energy is expressed as temperature, which is quantification of molecular kinetic motion.
Homeothermy = maintain constant temperature in face of changing external temperature. Do so be combination of behavioral adaptations and endothermy = generates on heat by metabolism.
Poikilothermy = body temperature equilibrates with external temperature - the so called “cold blooded” organisms, including plants.
Organism tolerances of thermal extremes (-60 to +60°C)
4. Ultimate source energy for most life on earth. Eception is tube worms in deep sea thermal vents that are chemoautotrophs that use naturally ocurring H2S as source of energy.
Ultraviolet (200-400 nm) - damaging to organic molecules (DNA – skin cancer in Tucson, John McCain) - absorbed effectively by ozone in the atmosphere
Near infrared 700-10,000 nm – too low energy to power photosynthesis
Visible or PAR 400-700 nm (micromols m-2 s-1) – like goldilox said about baby bear's poridge, "just right!”
Ultimate source energy for most life on earth. Eception is tube worms in deep sea thermal vents that are chemoautotrophs that use naturally ocurring H2S as source of energy.
Ultraviolet (200-400 nm) - damaging to organic molecules (DNA – skin cancer in Tucson, John McCain) - absorbed effectively by ozone in the atmosphere
Near infrared 700-10,000 nm – too low energy to power photosynthesis
Visible or PAR 400-700 nm (micromols m-2 s-1) – like goldilox said about baby bear's poridge, "just right!”
5. Since temperature of leaf is a function of energy balance, leaves can be warmer or cooler than surrounding air depending on ratesthat they absorb and dissipate energy.
Small leaves are close to air temperature because of efficient convection.
Lots of small leaved things in the desert. (Palo verde). Less reliant on evaporative cooling and water loss.
Other reduce absorbed shortwave radiation
- leaf hairs (brittlebush), cactus spines (barrel cactus)
- leaf waxes (cactuses)
- leaf orientation (Jojoba – branch in class)
Evaporative cooling (Cottonwood - 5 - 8°C cooler than air temperature)
Alpine plants - Radiation absorbing pigments in leaves, displaying tissues directly at sun, growing close to ground in cushion.
Since temperature of leaf is a function of energy balance, leaves can be warmer or cooler than surrounding air depending on ratesthat they absorb and dissipate energy.
Small leaves are close to air temperature because of efficient convection.
Lots of small leaved things in the desert. (Palo verde). Less reliant on evaporative cooling and water loss.
Other reduce absorbed shortwave radiation
- leaf hairs (brittlebush), cactus spines (barrel cactus)
- leaf waxes (cactuses)
- leaf orientation (Jojoba – branch in class)
Evaporative cooling (Cottonwood - 5 - 8°C cooler than air temperature)
Alpine plants - Radiation absorbing pigments in leaves, displaying tissues directly at sun, growing close to ground in cushion.
