By PRAGYANSHARMA POLAVARAPU (Vrs.Somanchi)
Organic chemistry from the view of a student of chemistry can be called “hydrocarbon chemistry”. There
is an interesting point to learn about first creation of hydrocarbons which are so necessary for
continuous existence of life . Were the hydrocarbons created
on ancient earth millions of years ago in the air or in the oceans or in soil.
Scientists say that as the “Hadean Era” on planet earth(a red hot
stony planet with all ocean water existing as hot vapour clouds) ended, there was steady cooling of earth’s
surface during hundreds of millions years. Earth’s sphere
started to cool extremely slowly from its depths . A stone mantle
formed all around it made of a few continent sized semi-solid rock plates
of 1800 miles thickness. Above the mantle a 20 to 30 mile
thick crust of granite and basalt rock formed. This was the
situation about 4000 million years ago and, after centuries-long
torrential rains amid frequent lightning, temperatures came down to 70 or
80 degrees centigrade in the oceans.
The atmosphere was filled only
with thick cover of gases like CO2,CO, Methane ,Sulphur and vast quantities water
vapor. There were thousands of volcanoes spewing all such gases for
millions of years amid incessant rain .There was centuries- long pouring rain
and heavy lightning existing every minute. It was truly an atmosphere of Hades,
the hellish atmosphere.
After further hundreds of millions of
years earth cooled further–scientists say, to about 30 to 40 degrees
centigrade. Scientist say that about 2000 million years ago the green
chlorophyll containing cyano-bacteria— perhaps floating in huge kilometers -wide
colonies on ocean’s surface in bright sunlight— started to make carbohydrate in
their body. The single-celled bacteria used carbon
dioxide and water vapor to create carbohydrate food and released oxygen
gas into atmosphere. Till then there was no free oxygen in atmosphere as
we know today. This process has been continuing for 2000 million years and by
600 millions ago (from present times) the atmosphere was fully
filled with oxygen gas.
During the last 600 million
years all the life forms—plants and trees,animals,fishes ,birds
,insects,reptiles etc of all sizes and forms developed . Millions of
species of creatures appeared and died due to suitability/unsuitability of
environment. There were severe ice ages that covered entire planet with ice for
millions of years! There was“tectonic movement” at some distant places on
earth’s crust here and there. Volcanoes ,flooding, vast erosion ,vast
changes in land levels and sea levels ,appearance of fold mountains etc
occurred—most of them extremely slowly over millions of yeas.
Only those species which could
adjust to changes in weather ,land and sea etc could survive. One million years
is un-imaginably long .It is equal to 10,000 centuries! Scientists say— after
examining hundreds of thousands of fossils and other evidence like well
preserved bodies in permafrost in Siberian regions etc— that all modern living
creatures developed during last 600 million years. Even 600 million years is a
period incomprehensibly long.All this is a very vast subject for others
scientific disciplines.
Since about 600 million years the
plant kingdom , trees big and small, spread over entire earth. Life forms
as we know ,plant life and animal life spread widely on all land. Giant forests
developed all over the world where roamed millions of animals since
about 500 to 600 million years ago. But interestingly it was the tiny
cyano-bacteria which started a new “food cycle” and created “carbohydrate” –the
first food on which all living beings plants, animals, insects ,fishes and
man all living creatures depend to this day! Even the lions and tigers have to
eat other animals which are herbivores to survive.
Let us go for a while to a far older
time —a time 1000 million years back. There were only microscopic single
celled creatures floating in oceans in kilometers wide colonies and
devouring one another for survival. The single celled creature had no nucleus
in their cells and they had soft transparent bodies without any hard limbs and
were just like microscopic size transparent plastic bags of water with a little
black DNA material inside . They had no developed body parts. They
only breathed oxygen dissolved in water and floated in huge colonies and
were at mercy of winds and waves and the heavy rains.
After the great “Oxygen revolution”
and after countless millions of years great forests developed all
over earth and millions of animals big and small lived and thrived in them as
there was lot of food both for herbivore and carnivores and even insects
and reptiles . During uncounted millions of years —millions or billions of
forest trees grew up and died and billions of animals were born and died and
all their remains were buried in deep layers of earth. Due to great heat coming
from center of earth the vast mountainous piles of organic
matter decomposed deep under layers of earth. The “ hydrocarbons” which are the
primary basic chemical compound for formation of all organic compounds in
bodies of all living things (both plant kingdom and animal kingdom) came out during
the millions of years of time. The “higher hydrocarbons” were
converted as the dark viscous oily mineral petroleum and the “lighter
hydrocarbons” like methane, ethane, propane,butane etc became a mass of pungent
mineral gases and were locked under huge rock plates and slowly leaked through
fissures and bubbled through miry land. Now we take out these liquid and
gaseous hydro carbons through petroleum wells, refine them in special petroleum
refineries and use them in the hundreds of millions of cars and motorbikes and
airplanes and diesel engines(and add a great burden of pollution on earth and a
headache to scientists and engineers).
At last we can understand and get the
answer. The hydrocarbons which are the base material for all living beings
(both plant kingdom and animal kingdom) were first assembled by cyano-bacteria
and later by the billions of trees and plants on earth’s surface. Only
millions of years later , the petroleum we pump from mines was
formed and the hydrocarbons existing deep inside earth were taken out by
man.
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