Lecture 9: Adaptation, Acclimation and Plasticity

Question 1

Physiology

Answer 1

analysis of the function of living organisms; applies physical and chemical methods to biology

Question 2

comparative:

Answer 2

Study of the diversity and modulation of highly conserved properties (physical and biochemical) of organisms

Question 3

Means that comparative physiology contributes to:

Answer 3

• Ecology - deals with the relations of organisms to one another and to their physical surrounding
• Evolution - correlates function with structure which can help determine relatedness

Question 4

Level of study:

Answer 4

organism: -cellular
- molecular
- genetic

• Compare adaptions of similar organisms in different environments
• Compare different organisms in similar environments

Question 5

Adaption:

Answer 5

Trait that improves an organisms performance (Fitness) in it environment.
–i.e. it is selected; organism that has this trait survives better and leaves more offspring to next generation
• Makes the organism more fit for current environment
-are heritable
-time scale
—evolutionary = long term

Question 6

Acclimatisation :

Answer 6

natural

Question 7

Acclimation :

Answer 7

experimental

Question 8

Acclimatisation & acclamation:

Answer 8

• Physiological compensatory response (short- term) to environmental change
• E.g., in the short-term, under low [O2] [concentration], the body makes more red blood cells to acquire more O2 in the body.
• E.g., in the short-term, under heat stress, vasodilation occurs to dissipate excess heat.
• Time scale – minutes to hours to days to weeks to months

Question 9

example to living in extreme environments: Himalaya & Andes

Answer 9

• high altitude living extreme
• highlanders
• problem as low atmospheric [O2] = hypoxia
• at 4000m, only 60% of [O2] than at sea level
• Tibetans have lived at 4000m >25K yrs
• Andean at 4000, for about half that time

RESULTS:
Amount of O2 saturation (4000 m)
• Andeans 2.6% greater than Tibetans
• Andeans are marginally “less stressed” at ~4000m than Tibetans in terms of O2 saturation but are more stressed with downstream consequences of this higher [Hb]

Question 10

how can you increase RBCs and therefore (Hb) Haemoglobin

Answer 10

through erythropoiesis by making EPO (erythropoietin)

Question 11

Tibetans vs Andeans altitude of response

Answer 11

also differs
–Tibetans not respond with increased Hb until ~4000m whereas Andeans respond at 1600m
• Tibetans require a much stronger stimulus and have smaller response

Question 12

Tibetan adaptions to high altitude

Answer 12

• Dominant autosomal gene for oxygen saturation
• Confers 5-6% higher oxygen saturation
• Genealogical, O2 saturation and female fertility data collected for 681 women
• Homozygous recessive mothers had lower number of surviving children due to increased infant mortality
• High altitude hypoxia acts as an agent of natural selection