Welcome back to know more about viruses!
Unknown and unseen (Seeing is Believing!) before
the eras of virology and electron microscopy,
viruses, billions of which can fit inside the eye of a
needle, are the oldest on Earth, roamed the Earth
— in their own microscopic way — hundreds of
millions of years before the mighty dinosaurs
(the longest complete dinosaur was 58 meters
(190 ft) long, 12 meters (39 ft) tall and weighed
over 120000 kg (260000 lb)), have been and
continue to be ubiquitous and omnipresent in all
parts of the biosphere where there is liquid water,
including soil, hot springs, on the ocean floor, high
in the atmosphere and deep inside rocks within the
Earth’s crust. They have survived the calamitous
extinction events hitting the earth like huge Asteroid
Hits, Mighty Cyclones / hurricanes and furious floods
like the Cretaceous–Paleogene extinction event,
which occurred approximately 65 million years ago
at the end of the Cretaceous period, caused the
extinction of all dinosaur groups except for the tiny
neornithine birds.Viruses even survive in extreme
places like near deep-sea vents.
We, humans, are composed of about 10 trillion
‘human’ cells. There are more than 1000 trillion
viruses on the surface of and inside our bodies.
There are more than 100 trillion bacteria on the
surface of and inside our bodies.
Most microbes do not cause disease (pathogenic) –
less than 5% are pathogens; most of them are
harmless commensals (peaceful co – existers); many
are even helpful to hosts like us and our environment.
Microbes generate at least half the oxygen we
breathe. Micro – organisms are vital to humans and the
environment, as they participate in the Earth’s
element cycles such as the carbon cycle and
nitrogen cycle, as well as fulfilling other vital roles
in virtually all ecosystems, such as recycling other
organisms’ dead remains and waste products
through decomposition. Microbes also have an
important place in most higher-order multicellular
organisms as symbionts. Many blame the failure
of Biosphere 2 on an improper balance of microbes.
Micro – organisms are used in brewing, winemaking,
baking, pickling and other food – making processes.
They are also used to control the fermentation
process in the production of cultured dairy products
such as yogurt and cheese. The cultures also
provide flavour and aroma, and inhibit undesirable
More on viruses and microbes in the next page!