HOW LIFE ORIGINATED ON EARTH?

 

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.