Resource Constraints Temp

macroclimate

large scale climate patterns that prevail over entire regions

determined by climate cells and topography

microclimate

small scaled climate patterns (can be down to cm)

deviate from the macro

determined by landscape, vegetation, or small topography (elevation, aspect, surface colour, depressions, etc)

elevation on microclimate

the timberline shows a shift with increasing elevation

as mean annual temp decreases trees are less able to survive (need 6.7* for 94 days per year to grow)

aspect on microclimate

north slopes have less solar radiation, more snow and more water leading to more forest growth

south slopes have more solar radiation, less snow, and less water leading for a more dominant grass land type ecosystem

vegetation on microclimate

trees and shrubs can cast shade, understories have colder temps and evaporation is decreased

surface colour on microclimate

lighter colours will reflect light so the surface wont increase in temperature (snow), while darker colours absorb light so the surface increases in temp (bedrock)

albedo

reflectivity of a landscape, how much light is reflected and does not get absorbed

so light coloured surfaces would have a higher __ than dark coloured

boulders and burrows on microclimate

some organisms live under rocks or underground in burrows

these create shade and allow animals to avoid heat during the day

aquatic temperatures

less fluctuation than air temperatures - usually between -4 to 32*

heat is absorbed by water as it evaporates, water gives up heat energy as it freezes

range of tolerance

the range of an environmental condition (abiotic factors) in which an organism can survive, grow and reproduce

species have optimal conditions within environmental thresholds, beyond this survival decreases and physiological stress ovvurs

range of tolerance and fundamental niche

one environmental condition such as temperature compared to all environmental conditions where a species may live

law of tolerance

the abundance and distribution of an organism can be determined by the deviation between location conditions (temp) and optimum set of conditions for a species

so the same factors which limit growth will affect abundance and distribution

plant range of tolerance

temperature limits photosynthesis in various species who have adaptations to different climates

differently adapted species have different ranges of tolerance and optima

principle of allocation

organisms have limited energy, when an organism allocates energy to one function, it reduces energy available to others

balance of costs vs benefits, adaptation to one set of conditions will reduce fitness in other environments

when you are at the margins of tolerance

die, migrate, acclimate, adaptations to extreme temps

death

avoid extreme temps by funnelling all energy to reproduction - offspring has a chance

ex annual plants seed before winter

migration

avoid extreme temperatures by moving to warmer regions

advantages outweigh the costs

ex birds, insects, mammals

acclimation

physiological or morphological changes in an organism in response to changes in the environment (temp, pH, humidity, etc)

NOT adaptation (but the ability to is an adaptation)

phenotypic plasticity

ex adjustment to high altitudes - generally reversible

physiological/morphological adaptations

to extreme temperatures

freeze tolerance - cryoprotectants

or in a polar bear - thick fur, body fat, short body appendages

freeze tolerance

production of cryoprotectants

example in wood frogs - freeze themselves and rehydrate in the summer

reduced metabolic activity adaptations

to extreme temperatures

hibernation or estivation (hot temps)

adaptation vs acclimation

an evolutionary process changing on the genetic level, not reversible VS and individual changes within an individuals lifetime - reversible

heat balance equation

Hs = Hm ± Hcd ± Hcv ± Hr - He

Hs - total heat stored, Hm - gain via metabolism, Hcd - conduction (ex soil or roots), Hcv - convection (wind), Hr- radiation, He - evaporation

plant heat balance in cold temps

dark coloured leaves, and leaf and flower orientation allow for increase Hr

cushion/compact growth allows for decreased loss from convection (wind)

smaller surface area ratio

plant heat balance in hot temp

decrease contact with ground, open growth form allows for increase loss from Hcv

reduce leaves and light surface and so Hr and Hcd also decrease

poikilotherms

body temperature varies with the environment

homeotherms

body temperature relatively constant regardless of environemt

ectotherms

control body temp using external energy

ex plants, fish, amphibians, reptiles and inveterbrates

sit in sun for warmth or get out of sun if too hot

low diversity in regions of cold climate

endotherms

control body temperature using internal energy such as metabolism or shivering/sweating

metabolic rate remains constant in neutral zones but increases when too hot or too cold

ex mammals and birds - allows for species to live in regions where temp gets colder than body temperature

endotherm heating/cooling

shivering to contract muscles and generate heat

sweating or panting will increase convective cooling

temperature regulation