Physiology 1: Adaptation, acclimation and plasticity Flashcards
What is an adaptation?
Any trait that increases the fitness of an organism in its environ = result of natural selection
Describe the features of an adaptation (e.g how they occur, time scale etc.)
- Organism that has this trait survives better and leaves more offspring in the next gen
- Trait is selected for
- Genetically determined, heritable
- Evolutionary time scales (very long)
- Behavioural adaptations → E.g bears hibernating over winter
What is acclimation?
Physiological compensatory response to environ change
Describe the features of an acclimation
- Short-term response
- Not heritable
- May be immediate, or build up over time
- Mostly experimental/ artificial
What is plasticity?
Ability of living organisms to change their ‘state’ in response to any stimuli
Describe the features of plasticity + examples
Occurs at any level of complexity: molecular, cellular, systemic and behavioural
Limited (can be adaptive and evolve)
E.g rockhopper penguins live in a variety of climates (subtropics to subartics)
E.g homeostasis in humans
What is acclimatisation?
Physiological compensatory response to environmental change
Describe the features of acclimatisation + example
Short term response to environ
Not heritable
May be immediate, or build up over time
Natural/ slightly longer
E.g adjustment of sheep to hotter temps by shedding wool
At high altitudes there’s low atmospheric O2, what does this mean for pO2 and Hb affinity?
High altitude: low atmospheric oxygen
High pO2, Hb high affinity, O2 binds readily
At low altitudes there’s low atmospheric O2, what does this mean for pO2 and Hb affinity?
Low altitude: Low pO2, Hb low affinity, O2 released
In the altitude case study, what were the results of measuring physiological stress (Hb) in both pop.s?
Andean pop. higher Hb conc than their lowland ancestors
Tibetan pop. no sig diff between ancestors
= diff in response to living at high altitudes
In the altitude case study, what were the results of measuring physiological stress (O2 saturation) in both pop.s?
Andean pop. lower O2 saturation than lowland ancestors
Tibetan pop. lower than Andeans
= suggests Andeans less stressed by hypoxia
What is the trade off of having higher Hb levels to deal with high alitiudes?
Higher Hb → more viscous blood → strains heart → whilst increased hB deals with hypoxia = trade off
What is adaptive plasticity?
Genetically controlled diff that confers an adaptive change in the extent or direction of a plastic response
What is heritability?
Proportion of total phenotypic variance attributable to genetic relationships among individuals