Thermal Biology Flashcards
Metabolism
Processes that provide an organism the energy it needs to survive and respond to its surroundings.
The sum of the chemical reactions within the body that convert food to energy molecules (e.g., ATP) used for life functions (e.g., growth, reproduction) and to sustain the cellular energy demands that support life (e.g., protein synthesis).
(Currie & Evans, 2021; Fry, 1947)
Fry Paradigm
Outlines the different ways in which environment impacts an organism.
What are the six categories for effects of the environment on organisms as per Fry (1947)?
- Lethal factors
- Masking factors
- Directive factors
- Controlling factors
- Limiting factors
- Accessory factors
Lethal Factors
An environmental effect that kills the organism.
Have two components:
1. the incipient lethal level
2. the effective time
(Fry, 1947)
Incipient Lethal Level
Level of a lethal factor beyond which an organism cannot survive.
(Fry, 1947)
Effective Time of a Lethal Factor
How long it takes an organism to die when exposed to a lethal factor beyond the incipient lethal level.
(Fry, 1947)
Masking Factor
An environmental effect that prevents another environmental effect from acting on an organism either fully or partially (e.g., sweating to lower temperature).
(Fry, 1947)
Directive Factor
An environmental effect that allows or requires an organism to respond in relation to a gradient of effect (e.g., light to see prey).
(Fry, 1947)
Controlling Factor
An environmental effect that governs metabolic rate (e.g., temperature).
(Fry, 1947)
Limiting Factor
An environmental effect that limits metabolic rate even if other factors changing would normally cause an increase in metabolic rate (e.g., oxygen concentration in water being at a certain level limiting the rate at which metabolism can occur).
(Fry, 1947)
Accessory Factor
An environmental effect that when combined with another effect (that is not lethal) increases the metabolic load on the organism too much causing it to die.
(Fry, 1947)
Zone of Tolerance
Zone in which an organism will never die from the effects of a particular effect.
(Fry, 1947)
Zone of Resistance
Zone in which an organism can resist a lethal factor for a period of time but will eventually die - this zone lies outside the incipient lethal levels.
(Fry, 1947)
How does the Fry paradigm relate to my work?
I think my work will contribute to the body of knowledge relating to each of my study species’ zones of tolerance for the various habitat variables I’m measuring.
Incipient Lethal Temperature
Temperature beyond which 50% of the population cannot survive indefinitely.
(Fry, 1947)
Thermal Tolerance
All temperatures an organism can withstand indefinitely.
(Fry, 1947)
Preferred Temperature aka Preferendum
Temperature at which animals congregate when they have multiple temperature options.
(Fry, 1947)
Final Preferendum
Where preferred temperature equals acclimation temperature - where all individuals ultimately congregate.
(Fry, 1947)
What distinguishes a controlling factor from a limiting factor?
A controlling factor impacts both the minimum and maximum metabolic rate whereas a limiting factor only impacts the maximum rate.
Also, more than one controlling factor can operate at the same time.
(Fry, 1947)
Optima
Level of an effect at which an animal can perform a certain activity best.
(Fry, 1947)
Why is understanding the effects of temperature on biological processes especially important right now?
Climate change is altering global temperatures changing the biogeographic distribution of species.
(Schulte, 2015)
Thermal Performance Curve (TPC)
Describes the effects of temperature on the rate of a biochemical, physiological, or behavioural process.
(Schulte, 2015)
What are the characteristics of TPCs?
They tend to be unimodal and left-skewed with 3 distinct regions:
- A rising phase as temperature increases,
- A plateau phase that encompasses the thermal optimum (Topt) for the trait, and
- A steep falling phase at higher temperatures.
(Schulte, 2015)
Homeotherm
An endotherm that keeps its internal temperature within a narrow range.
