lec 7 - Resource Constraints: Temperature

Vocabulary flashcards covering key concepts from Lecture 7 on temperature constraints, microclimates, thermal regulation, energy allocation, and physiological adaptations.

Macroclimate

Large-scale climate patterns over entire regions, determined by wind/climate cells and topography

Microclimate

Small-scale climate patterns (down to cm in size) - determined by landscape, vegetation, or small-scale topographic features

Is macroclimate or microclimate more important for orgaisms?

microclimate

What type of landscapes influence microclimates?

• elevation

• aspect/slope

• vegetation

• Albedo (surface colour)

• boulders & burrows

How does elevation influence microclimate?

increasing elevation =  decreases mean annual temp = sparser vegetation / trees

-trees need min temp of 6.4C for a min of 94 days/yr to grow

timberline (where trees stop growing on mountain) reflect a shift in ________ with ______ elevation

• microclimate

• increasing

How does aspect/slope influence microclimate?

Earth’s tilt - influences water availability

ex. Winter in N hem.
 -receives less solar radiation, more snow & more water = forests grow

-S  -receives more solar radiation, less snow & less water = grasses & shrubs grow

How does vegetation influence microclimate?

creates shade = decreases temp & water evaporation (more moisture retained in soil)

Albedo (surface colour)

reflectivity of a landscape surface - how much light reflected vs absorbed

How does Albedo (surface colour) influence microclimate?

snow = lighter colour reflects light = no temp increase = high albedo

bedrock = darker colour absorbs light = temp increase -= low albedo

How do boulders & burrows influence microclimate?

organisms adapted to live under rocks or in burrows - create shade and allow animals to avoid heat during the day

Why do temperature in water fluctuate much less than air temperatures?
ex. oceans fluctuates only between -4 to 32 °C.

• water has higher heat capacity than land (takes 5x energy for water to increase 1 degree compared to land)

• water absorbs heat as it evaporates & gives up heat as it freezes

• takes longer for water to release energy - water can act as buffer for coastal areas 

Range of Tolerance

lvl of ind. - entire range of ONE abiotic environmental condition (ex. temp) in which an organism can survive

- bell-shaped curve - peak = optimal range of conditions (can grow & reproduce)

-beyond optimal conditions 

organism uses energy to overcome metabolic stress (=survival but no growth)
-zone of intolerance = mortality

How is Range of Tolerance different than fundamental niche?

Range of Tolerance: one environmental condition
Fundamental niche: all enviro factors (abiotic and biotic)

Law of Tolerance

 lvl of pop. - abundance & distribution = greatest in optimal range

Temperature is a limiting factor of ____ ______ in plants
Diff plant species show diff ______ ___ _______and optima in photosynthetic rate along a _____ ________.
ex. desert shurb - optimal = 44C - boreal moss - optimal = 15C

• photosynthesis rates

• ranges of tolerance

• temperature gradient

Range of tolerance in plants is related to ….

phenotypic plasticity  - plants are adapting their photosyn. rates to diff enviro conditions 

Why can’t species have it all and be adapted to different temperatures?

energy limitation (evolutionary tradeoffs & principle of allocation)

Evolutionary Tradeoffs

adapting to one set of environmental conditions reduces an organism's fitness in other environments

Principle of Allocation

organisms have access to a limited energy,allocating energy to one function reduces the energy available for other functions = balancing energy budget (growth, reproduction, activity, maintenance)

What is an example of Principle of Allocation in cacti?

ex. cactus adapted to survive in desert at high temps

if you put cactus in boreal forest - increases energy for maintenance (so growth decreases)

How do organisms regulate body temp?

gaining / losing heat through heat balancing equation

Heat Balance Equation $H_s = H_m \pm H_{cd} \pm H_{cv} \pm H_r - H_e$

$H_s$ total heat stored in body
+ = $H_m$ metabolic processes generate heat
+/- = $H_{cd}$ is conduction (touching others/surfaces - plant touching soil), $H_{cv}$ convection (liquids, water & wind - lose heat if wind is colder than body), $H_r$ heat radiation (from any heat source - lose heat is surrounding are colder than body
- = $H_e$ evaporation

Surface Area to Volume Ratio (SA:V)

smaller organisms have a higher SA:V ratio, exchanging heat more rapidly with their environment than larger organisms.

How do plants in cold temps (arctic & alpine) use adaptations for heat balancing?

• dark colour leaves = absorb more heat (+Hr)

• leaf & flow orientation to follow sun (+Hr)

• cushion growth ,compacted close to ground, soil heats up during day (+ Hcd) & not as exposed to wind (- Hcv)

• smaller SA:V ratio

How do plants in hot temps (desert) use adaptations for heat balancing?

• light colour leaves & reflective surfaces (hairs) = reflects more heat (-Hr)

• decrease contact w ground  (-HCd) & open growth form = more wind ca travel through (+ Hcv)

• reduces leaves = larger SA:V ratio

How do skunk cabbages use thermogenesis to regulate body heat?

metabolism break down starches stored in plant & transfers heat to flowering structure =  attracts pollinators  

What are the 4 dimensions of temp regulation in animals?

body temp relative to enviro - poikilotherms (body temp varies) & homeotherms (constant)

organism controls body temp - ectotherms (external energy) & endotherms (internal)

Example of how ectotherms (plants, fish, amphibians, reptiles, invertebrates) ue heat balancing equation?

Hcd, Hcv, Hr
ex. turtle -  lay on warm rock (+Hcd) & basking in sunlight on dark rock (+Hr) - lying flat on surface = less wind (-Hcv) 

ex. alligator - in shaded area w cooler surface (-Hcd), not exposed to sunlight (-Hr)

Example of how endotherms (mammals, birds) use heat balancing equation?

Hm
colder temps = increases metabolic rate = shivering = increases tolerace to cold temps (until it gets too cold)
vs heat = sweat/pant

What is an advantage of endotherms over exotherms?

endothemrs - organisms can live in eviro where average temp is colder than body temp
exo - reptiles, lizards, snakes, turtles = higher diversity near equator 

freshwater invertebrates & fish (dimensions of temp regulation)

poik & ecto

most birds & mammals (dimensions of temp regulation)

homeo & endo

marine invertebrates & fish (dimensions of temp regulation)

homeo & ecto

Hibernation

A physiological state of prolonged reduced metabolic activity and inactivity used by organisms to survive extreme cold conditions.

Estivation

A physiological state of prolonged reduced metabolic activity and inactivity used by organisms to survive extreme heat and dry conditions.

Freeze Avoidance

A physiological cold adaptation where organisms remain active in sub-zero conditions by adjusting solute concentrations or producing antifreeze glycoproteins to lower the freezing point of body fluids.

Freeze Tolerance

A physiological cold adaptation involving inactivity and the production of cryoprotectants that allow fluids in extracellular spaces to freeze without damaging tissues.

Acclimation

Reversible physiological changes occurring in an individual organism in response to environmental changes within its lifetime.

Adaptation

An irreversible, evolutionary process across generations that alters genetics, anatomy, physiology, or behavior to enhance fitness in a specific environment.