2. What is Calcium?
Calcium is the chemical element with the
symbol Ca and atomic number 20. It has an atomic
mass of 40.078 amu. Calcium is a soft gray alkaline
earth metal, and is the fifth most abundant element
by mass in the Earth's crust. Calcium is also the fifth
most abundant dissolved ion in seawater by both
molarity and mass, after sodium
then chloride, magnesium, and sulfate.
3. Importance of Calcium in Life
Calcium is necessary for life
In early life, calcium helps build strong bones and
teeth
Helps with muscle contraction and other body
process
Plants need calcium to help in cell wall
development and their metabolism; stronger cell
walls protect from pathogens
4. Calcium in human bodies
From birth to death calcium is an essential element
for human beings. Besides its presence in bones and
teeth, the mineralized tissues which contain 99% of
the body’s calcium, it is present in ionized form in the
blood, extracellular fluids and within the cells of soft
tissues such as muscles. It is necessary for the release
of energy in muscular contraction, for nerve
transmission and the regulation of heart beat, must
be present for blood to clot, and influences the
transport function of cell membranes. The proper
balance of calcium with sodium, potassium and
magnesium ions maintains muscle tone and controls
irritability.
5. From the biosphere…
Calcium enters from biosphere in dust or from
organisms
Like phosphorous, there is no gaseous state so it does
not stay in the atmosphere
When animals die, the calcium in their bodies are
decomposed and go into soil
In the soil…
Water can carry calcium to or from soil through
weathering
When in the soil, calcium is in an insoluble form until it
is broken down by microbes into a usable form
Mineralization can store calcium in rocks
Calcium can be returned from root leakage
Calcium can be absorbed by plant roots
6. In plants…
When absorbed by plants, calcium is now in an
organic state
The calcium can continually be recycled
between the plant roots and soil
Or herbivores can eat the plants or drink the
water and the calcium returns to the biosphere
If the plant or animal dies, decomposers break
down the organism and calcium is returned to
water or soil
8. Occurrence
Calcium is not naturally found in its elemental state.
Calcium occurs most commonly in sedimentary
rocks in the minerals calcite, dolomite and gypsum. It
also occurs in igneous and metamorphic
rocks chiefly in the silicate
minerals: plagioclase, amphiboles, pyroxenes and
garnets.
