Hibernation enables
animals to survive cold conditions, and
estivation allows animals to survive the hostile conditions of
a hot, dry climate. When an animal estivates or hibernates, they enter a state of torpor, in which their
metabolic rate is significantly slowed. The animal can then postpone until its environment is more
conducive to its survival. A substance akin to antifreeze is present in the cells of some amphibians,
including the wood frog (
Rana sylvatica ), which preserves the integrity of the cells and prevents them
from freezing and bursting.
Water All living things need water because it is essential for cellular functions. Terrestrial organisms
have developed numerous adaptations to conserve water because they lose water to the environment.
•
Intriguing leaf characteristics like leaf hairs and a waxy cuticle help plants conserve water by
slowing down the rate at which it is lost through transpiration and convection.
•
Freshwater organisms are constantly in danger of having water rush into their cells due to
osmosis because they are surrounded by water. Organisms that live in freshwater
environments have developed a variety of adaptations to keep the concentration of solutes in
their bodies within acceptable ranges. The excretion of diluted urine is one example of an
adaptation.
•
Marine organisms are at risk of losing water to the environment due to osmosis because the
water around them has a higher solute concentration than the organism. For these organisms
to hold onto water and release solutes into the environment, morphological and physiological
adaptations are necessary.For example, Marine iguanas (
Amblyrhynchus cristatus ), sneeze out
235
water vapor that is high in salt in order to maintain solute concentrations within an acceptable
range while swimming in the ocean and eating marine plants

.
