Animals In The Extemes Flashcards
How is haemoglobin adapted at high altitude environments?
It has higher oxygen affinity
Small animals have a large surface area to volume ratio, what are the issues with temperature and water?
Temperature: risk of overheating and temperature loss during nights
Water: larger surface area leads to increased evaporation
What are the three main strategies in desert animals?
Evaders
Evaporators
Endurers
What do evaders do?
Avoid exposure to extreme climates due to rhythmic activity patterns, burrowing, estivation (summer sleep)
What do evaporators do?
Dependent on a reasonable water supply to allow them to cool down by the use of evaporation
What do endurers do?
Usually large mammals and can tolerate high fluctuations in body temperature and hydration
Where can microclimates in the desert occur?
10cm below the sand conditions are more stable
What are some examples of locomotor tricks in desert animals?
Alternating feet in desert lizards, sidewinder snakes and cartwheeling desert spiders
What are the morphological tricks of the desert snail in order to avoid over heating?
Highly reflective surface (95% reflection of sunlight)
Apex of shell is cooler inside and the snail will retract into this compartment during the day
What is Allen’s rule?
Animals adapted to cold climates have shorter limbs and body appendages than animals adapted to warm climates
What are the morphological tricks of the black tailed jackrabbit?
Specialised areas of bare skin which contains a network of blood vessels for heat exchange (“radiators”)
What is the dark flank for in the Thompson’s gazelle?
The dark flank absorbs heat better compared to the rest so they can orientate themselves to control body temperature
What percentage of water loss can camels endure?
30%
Humans 10-12%
What happens to an animal when they become dehydrated?
The blood cells shrink which leads to death because you cannot extract any oxygen
How can camels replenish the water deficit?
By drinking very rapidly (200L in 3 mins)
Water is temporarily stored within the gut in order to prevent big fluctuations in plasma osmolarity
What is another way to conserve water?
Urinate less through having more concentrated urine
Where does most of the absorption of water and salts take place in the kidney?
The first part of the tubule called the proximal convoluted tubule
And loop of Henle
What do the ascending and descending limbs of the loop of Henle do?
Thin descending limb contains water channels but it is impermeable to salts
Thick ascending limb contains salt transporters but it is impermeable to water
Do desert animals have long or short loops of Henle and why?
Very long loops of Henle because the longer the loop the more concentrated the gradient and urine
What is special about the kangaroo rat?
They have a perfect water balance so there is no need for them to drink any water at all
What are the physiological tricks of conserving water in desert beetles?
Have a condensation chamber for water which evaporates from spiracles
