10b bio Flashcards
challenges of cold env:
- low temp
- piercing winds
- low availability of nutrients
- Precipitation as snow
challenges of cold env: low temp
reactions required for life may slow down or stop, water may freeze cell contents and rupture cells
challenges of cold env: peircing winds
can exert strong forces on plants and increase the heat lost by an organism
challenges of cold env: low availability of nutrients
lack of it restricts macromolecule synthesis & growth rate
challenges of cold env: percipitation as snow
makes it difficult to obtain the liquid water required for their survival
animals adaptations: structural
insulation, SA:V
animals adaptations: structural - INSULATION
thick layer covering body or fat
animals adaptations: structural - SA:V
animal will release heat slowly, increasing time it takes for body temp to drop - the more you resemble a sphere the easier it is to maintain a constant body tem
animals adaptations: physiological ecto and endo
greater proportion of endo than ecto bc animals cannot obtain heat from an env with a lower temp than their body, theyll burrow underground
animals adaptations: physiological
torpor, circulation, Countercurrent circulation,
animals adaptations: physiological - torpor
hibernation
animals adaptations: physiological - countercurrent circulation
Uses the heat in blood travelling from the heart, to heat cool blood returning from the animals periphery, core body temperature is not lowered.
animals adaptations: behaviour
- seeking shelter
- reducing exposed surfac area
- hudding
- Migrating to warmer climate
animals adaptations: behaviour - seeking shelter
surrounding themselves in microenvironment, den burrow
animals adaptations: behaviour - reducing exposed surface area
Objects with lower SA:V ratios will release less heat. Many animals will hide or protect their peripherals as the temperature drops, curl up, stand on one leg
animals adaptations: behaviour - huddling
artificially decrease their individual SA:V ratio, decreasing the amount of heat released
Adapting to the cold: plants
Freezing presents stress for alpine and cold-adapted plants, where the barrier between tolerable and intolerable can be drastic
presents number of problems:
- Enzyme & protein driven reactions progress slowly at lower temperatures
- ice crystals within the cell can rupture cell membranes and the plant vascular system cannot transport nutrients when they are blocked
Deciduous trees
drop leaves to void harsh conditions
adv: less branches break, less water and energy to survive, avoid leaf freezing tissue
seed dormancy
unable to germinate during specific time under certian env conditons
