Slides in this set
Water is essential to all living
· Physiological solvent most chemical
reactions in cells take place in dissolved water.
· Transport water is the solvent in blood and
sap. Transports oxygen, carbon dioxide,
· Temperature control evaporation of water
from the skin to cool the body (sweat)
Key term : Physiological function - any
substance that is involved in a chemical
reactions in a living organism has a
physiological function…read more
Anomalous expansion on freezing because
ice floats it keeps the cold air above separate
from the water below, which prevents it from
cooling as much as it would without the ice.
This prevents lake from freezing solid
· High specific heat capacity moderates the
rate and size of temperature changes, cooling
and heating slowly
· Provision of aquatic habitat rivers, lake and
Appropriate temperature range
Most areas of earth are + 0°c which allows liquid
water to be present.
Enzymes require liquid water as a solvent, so
most organisms are found within 0°c-40°c
Thermophilic bacteria can withstand much
higher temperatures sometimes 80°c +…read more
Light and radiation
· Sunlight provides the energy for photosynthesis
· Heat the source of energy for the water cycle and the
heating of earth
· Little harmful UV and ionising radiation
Some of these are a result of the position of earth and some
are a result of the features of earth itself.
· Distance from the sun light levels and temps.
· Daily rotation duration of days and nights, and therefore
· Tilted axis seasonal variation
· Molten layers beneath crust produces magnetic field
which deflects harmful radiation coming from sun…read more