Adaptation, Acclimation and Plasticity Flashcards
What is an adaptation?
A trait that increases the overall fitness of an organism
What is an adaptation?
A trait that increases the overall fitness of an organism
How are traits passed on?
If the trait is beneficial, organisms will survive to reproduction and trait is passed on to the offspring. Trait is selected for and is genetically determined, therefore heritable
How are traits passed on?
If the trait is beneficial, organisms will survive to reproduction and trait is passed on to the offspring. Trait is selected for and is genetically determined, therefore heritable
What is plasticity?
The ability of living organisms to change their state in response to any stimuli. Occurs at any level of complexity
What is acclimatisation?
Physiological compensatory response to the environment. It isn’t heritable. May be immediate of build over time. Is often experimental
What is any example of plasticity?
Rock hopper penguins are present at a variety of climates, from subtropical to subarctic climates, which os due to the species ability to express different strategies and foraging behaviour
Whats the difference between acclimation and acclimatisation?
Acclimation is under experimental condition e.g. in the lab, acclimatisation is natural
What happens to barometric pressure and atmospheric oxygen at high altitudes?
Both are low, meaning fewer oxygen molecules in a breath of air
How is oxygen transported round the body?
Oxygen from the lungs binds to harm groups in haemoglobin. There are 4 binding sites on each Hb, Oxygen is released from the haemoglobin into the issues that need it. Red blood cells transport oxygen around he body.
What is oxygen saturation?
The % of haemoglobin binding sites that carry oxygen
What is the haemoglobin oxygen affinity?
how readily hemoglobin acquires and releases oxygen molecules into the fluid that surrounds it
What happens to oxygen transport at high altitudes?
Oxygen transport system must respond to maintain sufficient tissue oxygen concentration, otherwise hypoxia may occur
What are the questions asked in the case study of Andeans and Tibetans living at high altitudes?
Do the Tibetans and Andeans have the same/different physiological responses to low atmospheric oxygen?
Are these responses heritable?
How does the measured response influence fitness?
How long have the Andeans and tibetans lived at 4000m for?
Andeans for 13 000 years, tibetans for 23 000 years
What is erythrocytosis?
an increase in the number of circulating red cells above the gender-specific normal level.
What did they find when measuring the degree of physiological stress in [Hb] shown by the Andeans and Tibetans?
Andeans had higher [Hb] than their closest ancestors living at low altitudes
No difference in [Hb] between Tibetans living at high altitude and their closest ancestors living at low altitudes
What did they find when measuring the degree of physiological stress in oxygen saturation shown by the Andeans and Tibetans?
Andeans and Tibetans had lower oxygen saturation than their closest ancestors living at low altitudes
Andeans had higher oxygen saturation than Tibetans, suggests Andeans were less stressed by hypoxia at the same altitude
Do tibetans and andeans have the same/different physiological responses to low atmospheric oxygen?
No, tibetans had a similar [Hb] saturation to lowlanders, whereas andeans had high, which shows that elevation in [Hb] is not a universal response to high altitude hypoxia
What are the downstream consequences of hypoxia?
Higher [Hb] -> viscous blood -> strains heart. Its a better to deal with hypoxia, but is a trade off effect
Are responses in [Hb] heritable?
Both Tibetans and Andeans had high heritability
Potential for natural selection to act in both
samples
Are responses in oxygen saturation heritable?
No significant heritability in the Andean sample
Significant heritability in the Tibetan sample
How was oxygen saturation heritable in the Tibetan sample?
Dominant autosomal gene for oxygen saturation
Confers 5 – 6% higher oxygen saturation
Individuals with 1 or 2 copies of this allele
experience less physiological hypoxic stress than those who are homozygous recessive at this locus
What data was collected from the Tibetan region?
Oxygen saturation
Genealogy
Female fertility
How does the measured response influence fitness?
No association between presence of
oxygen saturation gene and the number
of pregnancies or number of live births
Homozygous recessive mothers had lower
number of surviving children (~1.6) compared to mothers with the oxygen saturation gene (~3.7)
Increased infant mortality rates in homozygous recessive mothers
