Life

This is one of the greatest challenges in modern science because it has no general definition due to its diversity. Someone may define life as simply reproduction, but viruses only reproduce while in a living medium, so can we still call that life? How did life come about? Why do we have plants, and other organisms? Ever since the origin of man, we have searched the globe for our origin. Some have told stories which are passed to their kids, while others looked for evidence. Our earth is about 4.5 billion years old and the oldest life form is about 3.5 billion years. But how did it come about? Astrobiologists have studied the origin of life on earth and proposed several hypotheses of the origin of life. I would state the two most popular ones:

1. Extra-terrestrial origin: Many astrobiologists
believe that life came from a distant planet and
began to evolve here on earth. This hypothesis
is found on the observation that some asteroids
that landed on earth sometime ago had L-amino
acids on its surface. Now the striking thing is
that under extreme conditions we would look at
later, both L and D amino acids are formed in
reactions. But living things prefer L amino acids.
Could it be that life in other planets used L-amino
acids and it became the substance which we used to
evolve? Who knows??

2. Extreme conditions: This hypothesis believes
that life was formed in extreme conditions here
on earth. This is founded on the observation
that if minerals are bubbled under high
temperature, molecules necessary for life are
produced. For example, if methane, carbon dioxide,
water, hydrogen, and ammonia are bubbled
under high temperature, I get both D @ L amino acids.
Please note that 3.5 billion years ago earth was extremely hot and
was filled with those gases.
So if life evolved like that, how did they feed?
These cells mostly survived at hydrothermal
water sites. Now these sites contained mineral
deposits at it's lower part, and these minerals
would melt which the cells would feed on.
Some organisms lost their use of locomotion
following Lamarck’s law on use and disuse. Lynn
Margulis proposed a theory that says eukaryotic
organisms were formed as a result of the
encapsulation of the mitochondria and chloroplast.
So since some organisms contained chloroplasts,
they had no need for motility thus lost the use
for it.
Though I am speaking basically of earth-like life.
But what about extra terrestrial life? We have
found none though there are moons and distant
planets we think might hold , for example, Europa One
of Jupiter, Titus which is Saturn’s moon,
Kepler 186f, etc. So we are keeping our fingers
crossed hoping we find life sometime soon. But
I remain positive.

Valentine O.
Gfaze Team