HOW
LIFE ORIGINATED ON EARTH?
Introduction: The
exploration of living organisms, encompassing plants, animals, and humans,
constitutes a vibrant domain within life science. Central to this exploration
is the fundamental question: what constitutes "LIFE"? Life is
commonly defined as the capacity of an organism to reproduce, grow, harness
energy through chemical processes, and utilize external materials. However,
scientists and philosophers have long grappled with two pivotal inquiries
concerning life's origins:
1. How did life emerge on Earth?
2. What mechanisms underlie the diversification of
organisms across the planet?
To embark on the quest
for answers, it is imperative to understand the formation of Earth and how its
internal dynamics foster life. Evidence suggests that Earth, along with other
celestial bodies in the solar system, coalesced approximately 4.5 to 5 billion
years ago. Initially, Earth comprised two primary components: a solid
lithosphere and a surrounding gaseous envelope constituting the atmosphere. As
the primitive Earth gradually cooled below 1000°C, liquid elements condensed,
forming the hydrosphere.
The Earth, in its evolved state, delineates into
three distinctive regions, delineated as follows:
1. Baryosphere: Serving
as the central core, the baryosphere is replete with molten magma rich in iron
and nickel. Comprising two discernible zones—the inner core (~800 miles radius)
and outer core (~1400 miles radius)—the baryosphere is crucial to Earth's
magnetic field dynamics.
2. Pyrosphere: Situated
as the intermediary layer, also referred to as the mantle, the pyrosphere spans
approximately 1800 miles in thickness. Predominantly composed of silica,
manganese, and magnesium, the pyrosphere plays a pivotal role in Earth's
geological processes.
3. Lithosphere: Forming
the outermost layer, known as the crust, the lithosphere spans 20 to 25 miles
in thickness. Comprised chiefly of silica and aluminum, the lithosphere is the
locus of geological activity, including tectonic plate movements and volcanic
eruptions.
Understanding the
intricate interplay of these Earthly components is foundational to unravelling
the mysteries of life's origins and the proliferation of diverse life forms
across our planet.
For
the sustenance of life following critical conditions are required:
1. Primitive Earth Atmosphere:
In its early stages, Earth's atmosphere was primarily composed of gases like
hydrogen and hydrogen compounds, such as methane (CH4) and ammonia (NH3), with
minimal oxygen content. Gravitational forces retained these gases, creating a
reducing environment conducive to the synthesis of organic compounds from
inorganic substances.
2.
Availability of Inorganic Raw Materials: Inorganic materials on
Earth interacted to generate the organic compounds necessary for the emergence
of life.
3. Diverse Energy Sources:
Primitive Earth accessed energy from various avenues, including:
- Solar radiation
- Electric discharges
- Volcanic eruptions
- Geothermal heat
- Cosmic rays
- Radioactive decay processes
4.Time:
The
timeline for the development of life on Earth was extensive, spanning nearly
one billion years from the planet's formation. Such a protracted duration
allowed for chemical reactions to occur without the aid of enzymes,
contributing to the eventual appearance of life forms.
These foundational
conditions collectively facilitated the emergence and sustenance of life on
Earth.
Theories
of origins of life on Earth
Several major theories
have been proposed to elucidate the origins of life on Earth. These theories
include:
1.
Theory of Special Creation: This theory posits that life on
Earth was created by a supernatural force, often conceptualized as a deity such
as God. According to Christian belief, for instance, God created the universe,
planets, animals, plants, and humans in six natural days. Similar beliefs are
echoed in other religious traditions. Key tenets of the theory of special
creation include:
A. Simultaneous Creation:
All living organisms were purportedly created on the same day, displaying no
discernible differences in appearance.
B.
Static Forms: Organisms were created in their present forms, with no room
for evolutionary changes.
C.
Fully Developed: Organisms' bodies and organs were presumed to be fully
formed and equipped to sustain life, without requiring adaptation.
OBJECTIONS
TO THE THEORY OF SPECIAL CREATION:
a.
Religious Basis: The theory was primarily rooted in
religious belief systems, lacking empirical evidence to substantiate its
claims.
b.
Lack of Experimental Support: There was a dearth of
experimental evidence supporting the assumptions posited by the theory.
c.
Contradictory Fossil Evidence: The age of various
fossils contradicted the notion that all living organisms appeared
simultaneously on Earth.
These objections
challenge the credibility of the theory of special creation, highlighting the
need for alternative explanations grounded in scientific inquiry and
evidence-based reasoning.
