Physiology 1: Adaptation, acclimation and plasticity Flashcards

1
Q

What is an adaptation?

A

Any trait that increases the fitness of an organism in its environ = result of natural selection

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2
Q

Describe the features of an adaptation (e.g how they occur, time scale etc.)

A
  • 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
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3
Q

What is acclimation?

A

Physiological compensatory response to environ change

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4
Q

Describe the features of an acclimation

A
  • Short-term response
  • Not heritable
  • May be immediate, or build up over time
  • Mostly experimental/ artificial
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5
Q

What is plasticity?

A

Ability of living organisms to change their ‘state’ in response to any stimuli

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6
Q

Describe the features of plasticity + examples

A

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

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7
Q

What is acclimatisation?

A

Physiological compensatory response to environmental change

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8
Q

Describe the features of acclimatisation + example

A

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

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9
Q

At high altitudes there’s low atmospheric O2, what does this mean for pO2 and Hb affinity?

A

High altitude: low atmospheric oxygen
High pO2, Hb high affinity, O2 binds readily

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10
Q

At low altitudes there’s low atmospheric O2, what does this mean for pO2 and Hb affinity?

A

Low altitude: Low pO2, Hb low affinity, O2 released

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11
Q

In the altitude case study, what were the results of measuring physiological stress (Hb) in both pop.s?

A

Andean pop. higher Hb conc than their lowland ancestors
Tibetan pop. no sig diff between ancestors
= diff in response to living at high altitudes

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12
Q

In the altitude case study, what were the results of measuring physiological stress (O2 saturation) in both pop.s?

A

Andean pop. lower O2 saturation than lowland ancestors
Tibetan pop. lower than Andeans
= suggests Andeans less stressed by hypoxia

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13
Q

What is the trade off of having higher Hb levels to deal with high alitiudes?

A

Higher Hb → more viscous blood → strains heart → whilst increased hB deals with hypoxia = trade off

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14
Q

What is adaptive plasticity?

A

Genetically controlled diff that confers an adaptive change in the extent or direction of a plastic response

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15
Q

What is heritability?

A

Proportion of total phenotypic variance attributable to genetic relationships among individuals

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16
Q

What do the results of the altitude case study suggest?

A
  • Population genetic diffs
  • Higher O2 saturation allele might be favoured by natural selection
17
Q

How does the presence of the O2 saturation gene in Tibetan pop. influence fitness?

A

No association between presence of O2 saturation gene and the number of pregnancies / live births
Homozygous recessive mothers = lower no. of surviving children compared with the O2 saturation gene
Increased infant mortality rates in homozygous recessive mothers
= Life stage that the O2 gene is acting upon is the infant / child stage