Lecture 7 Flashcards
Range of Tolerance
range of an environmental condition in which the organism can live
Optimum performance in range of tolerance
- further away from middle, the more negatively affected an organism
Law of tolerance
species have optimal survival conditions within environmental thresholds
Macroclimate
large-scale climate patterns
determined by climate cells & topography
Microclimate
determined by small-scale topography (elevation, mountain aspect, vegetation, surface colour, etc.)
Albedo
Lighter colours reflect light
darker colours absorb light
high albedo = more reflective = light colours
Temperature in aquatic movements
Temp fluctuate less in water because of water’s high heat absorption
Water temperature is stable
latent heat of fusion and vaporization (temp remains constant as state changes)
Principle of Allocation
organisms allocate energy to different functions (growth, maintenance, reproduction, activity)
allocation has costs and benefits
evolutionary tradeoffs
adapting to one environmental conditions generally reduce fitness in other environments
4 Strategies organisms can do when at the margins of tolerance
- Die
- Migrate
- Acclimate
- Adaptations to extreme temp
Death (strategy at margin of tolerance)
organism allocates all energy to reproduction, gives offspring better chance
Migrate (strategy at margin of tolerance)
migrate to warmer regions
advantages of migration outweigh costs of migrating
Acclimation (strategy at margin of tolerance)
- is NOT an adaptation but the ability to acclimate is an adaptation
- phenotypic plasticity
Adaptations to extreme temps
Physiological and morphological adaptations, prolonged state of metabolic inactivity
Polar bears: thick fur, body fat, short body appendages
Hibernation
prolonged state of metabolic inactivity, adaptation to cold temp
Estivation
prolonged state of metabolic inactivity, adaptation to hot temp
Heat balance equation
Heat stored = Heat gain/loss (metabolism, conduction, convection, radiation and evaporation)
Plant adaptations to heat: Arctic
- dark coloured leaves (low albedo = high absorb)
- cushion growth form
- smaller surface are: volume ratio
Plant adaptations to heat: Desert
- decrease contact with the ground
- open growth form
- reduced leaf size
- reflective light surfaces
Arctic vs Desert Plants
Arctic: increased heat gain from conduction and radiation and decreased heat loss from convection
Desert is opposite
Temperature regulation in animals
Poikilotherms: body temp varies with environment
Homeotherms: body temp constant regardless of environment
How organism controls body temp
Ectotherms: uses external energy (cold blooded)
Endotherms: uses internal energy (warm blooded)
Examples of ectotherms
plants, fish, amphibians, reptiles, invertebrates
