Recent studies indicate that complex life on our planet emerged approximately 1.5 billion years sooner than initially believed. Here we examine some leading hypotheses about how life first originated.
Throughout the ages, humans have pondered over the beginnings of life on our planet and the essence of existence itself—questioning primarily our origins and our ultimate destiny.
This query encompasses fundamental fields such as chemistry, biology, and physics, along with philosophy, psychology, and aspects of faith. Initially, early scholars were involved across various domains of inquiry. However, these foundational sciences are typically seen as more exact and straightforward to quantify compared to the others, which is why modern researchers often concentrate their efforts primarily on them.
During the 19th century, French chemist Louis Pasteur showed that life invariably arises from preexisting life. Whether they be plants, animals, or microorganisms, each reproduces within its own species.
However, what about the initial organism? If it emerged from non-living matter, at what point and through which processes did this occur?
Life could potentially be far more ancient than our previous assumptions.
A research conducted at Cardiff University in Wales, UK, indicates that complex life on our planet may have started 1.5 billion years before what was initially believed. The team asserts they discovered indications within Gabon’s rock formations suggesting favorable living conditions existed around 2.1 billion years ago.
Published in the journal Precambrian Research The research indicates that approximately over 2 billion years ago, the clash between two continental plates generated a fertile setting conducive to the development of complex life forms.
This would have generated phosphorus and marine oxygen essential for the shift from unicellular organisms to more advanced forms of life.
However, their existence was brief — it seems these complex lifeforms were restricted to an inland sea and could not expand globally.
This study questions the long-held scientific agreement that complex animals first emerged 635 million years ago, proposing instead that there was an earlier unsuccessful bid for more intricate forms of life on our planet.
What alternative theories are there regarding the beginning of life on Earth?
Several researchers have voiced skepticism regarding the recent discoveries and urged for additional studies to be conducted.
However, this research has reignited discussions regarding how complex life originated on our planet.
Throughout the last hundred years, scientists have created several
In this section, we examine several of the most common ones.
1. The Theory of Primeval Broth
A widely accepted hypothesis is the "primordial soup" theory, suggesting that life emerged from organic molecules in an early ocean.
British biologist Charles Darwin (1809-1882) was the pioneer who proposed that life might have originated in "a warm little pond."
It wasn’t until the 1950s that his hypothesis underwent experimentation. Harold Urey, an esteemed American chemist and Nobel laureate, along with another scientist named Stanley Miller, who specialized in chemical evolution, replicated a primeval environment within a lab setting. Inside this enclosed system, they combined substances like water, methane, ammonia, and hydrogen gases. To mimic lightning’s role as a triggering factor, electrical discharges were introduced into their apparatus.
Following several days, amino acids, which are the fundamental components of life, had developed.
2. The concept of cosmic life
A fascinating theory posits that earthly life initially originated beyond our planet, originating from outer space. This idea suggests that living organisms or the fundamental building blocks required for life were transported from space and took root on Earth.
This train of thought does not pinpoint precisely where life began or in what shape it came to our planet. However, the predominant theory suggests that life might have been delivered via a meteorite loaded with microorganisms colliding with Earth.
The initial advocates for this concept included British astrophysicists Fred Hoyle and Chandra Wickramasinghe. During the 1970s, their research indicated that comets hold substantial amounts of organic material capable of initiating life on planets like Earth.
3. The hypothesis of hydrothermal vents
The hydrothermal vent hypothesis proposes that life on Earth might have originated at the bottom of the oceans near these hydrothermal vents. Such vents are essentially cracks in the seafloor from which emanate heated water filled with minerals.
Michael Russell, a British geologist associated with the NASA Astrobiology Institute, suggested that alkaline hydrothermal vents releasing hydrogen, hydrogen sulfide, and methane might have offered optimal circumstances for generating basic organic compounds.
Even though the surroundings of hydrothermal vents are deemed harsh—these areas can get as hot as 400°C (752°F)—there are microbes that thrive here through chemosynthesis.
Chemosynthesis is a biological process where microorganisms produce their own sustenance. Instead of relying on light, they utilize energy derived from chemical reactions. This capability enables them to thrive in environments devoid of sunlight, like the deep-sea bed.
4. The RNA world
The RNA world theory suggests that far prior to the presence of DNA and proteins, earthly life was centered around an adaptable molecule known as RNA (ribonucleic acid).
DNA (deoxyribonucleic acid) enables organisms to grow, endure, and replicate. These DNA sequences transform into messages or guidelines that facilitate the creation of proteins—these intricate molecules play a crucial role in nearly all bodily functions—and sustain life.
On the contrary, RNA fulfills these two crucial roles for living organisms: It holds genetic data and serves as a catalyst for vital chemical processes.
During the 1980s, chemists Thomas Cech and Sidney Altman uncovered ribozymes—RNA molecules possessing catalytic properties—and consequently received a Nobel Prize for their discovery.
Scientists have suggested that early life forms may have relied on RNA molecules capable of self-replicating and facilitating basic chemical reactions before the emergence of modern organisms. Over time, these functions were taken over by proteins, which serve as more effective catalysts.
Various hypotheses exist regarding the beginnings of life. However, these are the ones that have garnered the most focus within the scientific community.
Everyone—including the most recent findings from Cardiff University—emphasizes the intricacy of this issue that still captivates and puzzles us in modern times.
Edited by: Zulfikar Abbany
Primary source:
A recent study from Cardiff University suggests that complex life on Earth emerged approximately 1.5 billion years sooner than previously believed, according to findings released on July 29, 2024. https://www.cardiff.ac.uk/news/view/2830233-complex-life-on-earth-began-around-1.5-billion-years-earlier-than-previously-thought,-new-study-claims
Author: Fernando Mateos Frühbeck
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