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Polar Gigantism and Climate Change
1.
Polar Gigantism andClimate Change
Almaz Assanov 11 A
2.
Polar bears and penguinsThe key danger for polar bears posed by
the effects of climate change is malnutrition
or starvation due to habitat loss. Polar bears
hunt seals from a platform of sea ice. Rising
temperatures cause the sea ice to melt
earlier in the year, driving the bears to shore
before they have built sufficient fat reserves
to survive the period of scarce food in the
late summer and early fall. Reduction in seaice cover also forces bears to swim longer
distances, which further depletes their
energy stores and occasionally leads
to drowning. Thinner sea ice tends to deform
more easily, which appears to make it more
difficult for polar bears to access
seals. Insufficient nourishment leads to lower
reproductive rates in adult females and lower
survival rates in cubs and juvenile bears, in
addition to poorer body condition in bears of
all ages.
3.
What’s the gigantism?• Deep sea gigantism – tendency of deep-sea creatures to grow to sizes
far exceeding those of their shallow-water counterparts
4.
Reasons for this1) High pressure
2) Scarcity of food
3) Absence of sunlight
4) Low temperature
5.
AdaptationsEating marine snow(scraps of falling food) + low temperature=> small
metabolic rate + lack of gravity => huge, slow, long living organism
6.
Positive sidesKleiber’s rule
More efficient use of food because of as body volume increases, the surface area
increases more slowly.
Big sized animals can store more energy (reserve mass), so deep sea creatures have
opportunity to sustain long journeys.
7.
Polar gigantism?Bergman’s rule + the lowest temperature + the oxygen richest water