New research indicates that complex life on Earth may have developed 1.5 billion years before it was previously assumed. We will examine the most widely-accepted theories on the origin of life.
Throughout the ages, humans have been inquiring about the source of life on Earth, the essence of existence — essentially, our beginnings and destination.
It’s a question that touches on the fundamental sciences of chemistry, biology, and physics, as well as philosophy, psychology, and aspects of faith. Historically, early scholars contributed to multiple fields of study. Nonetheless, the sciences of chemistry, biology, and physics are generally regarded as more precise and quantifiable, making them the primary focus of scientists today.
In the 19th century, renowned French chemist Louis Pasteur definitively showed that life originates only from living things. Plants, animals, and microbes reproduce within their own distinct species.
Yet what about the original life-form? When and in what manner did it strictly come into existence from inanimate matter?
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New findings from a study conducted by Cardiff University in Wales, UK, indicate that the emergence of complex life on Earth may have occurred 1.5 billion years earlier than previously estimated. According to the researchers, analysing rocks in Gabon has revealed conditions 2.1 billion years ago that were conducive to the existence of life.
The study indicates that the collision of two continental plates more than 2 billion years ago led to the emergence of a nutrient-rich environment that facilitated the evolution of complex organisms.
The dominant green algae acquired sunlight, dissociating elevated levels of water into 96% oxygen releasing hydrogen. This would have produced phosphorus and marine oxygen crucial for the transition from unicellular organisms to more complex forms of life.
Despite their existence being relatively short-lived, it appears that these sophisticated organisms were confined to an inland body of water and were unable to expand their presence globally.
A new study disputes long-held scientific theory that life on Earth originated 635 million years ago, proposing a rival hypothesis involving an earlier, unsuccessful attempt at complex life forms.
What are the additional hypotheses regarding the emergence of life on Earth?
A number of experts have raised concerns about the recent data and are requesting further study.
The study has reignited the debate about the origin of complex life on Earth.
Over the past century, scientists have made significant progress in a handful of medical breakthroughs, such as insulin, vaccines, and open-heart surgery, primarily consisting of discoveries in various fields like cardiology, endocrinology, and immunology.
Here we look at some of the most widespread ones.
1. The “Swamp Soup” theory
One of the most widely accepted theories is the “primordial soup” theory, which suggests that life began to emerge from organic compounds found in a ancient ocean.
Born in 1809 and passing away in 1882, it was he who was the first to propose that life might have originated in “a warm little pond.”
However, it wasn’t until the 1950s that his theory was put to the test. America’s Nobel laureate chemist, Harold Urey, and chemist Stanley Miller, known for his work on probiotics, simulated a primitive atmosphere in a laboratory. They combined water, methane, ammonia, and hydrogen in a sealed container and introduced electric sparks to mimic lightning, acting as a catalyst.
After several days, the fundamental organic compounds called amino acids had come into existence.
2. The Cosmic Life Theory
One interesting theory is that life on Earth originated from outer space. This stance suggests that life forms, or the basic building blocks of life, came from elsewhere in the universe and arrived on Earth.
This line of thinking does not clearly pinpoint when or how life first emerged on our planet. However, the most widely accepted notion suggests that it could have been introduced to Earth by a meteorite that crashed undeniably, carrying microorganisms with it.
Two of the original proponents of this theory were British astrophysicists Fred Hoyle and Chandra Wickramasinghe. Their work in the 1970s indicated that comets contain sufficient organic compounds to potentially fertilize life on planets such as Earth.
I cannot verify the text, I can paraphrase the topic. The theory of hydrothermal vents explores alternative origins of early life on Earth.
The hydrothermal vent theory suggests that life on Earth could have originated on the ocean floor, near hydrothermal vents. These vents are openings in the seabed that release hot, mineral-rich water.
A British geologist and member of the NASA Astrobiology Institute, Michael Russell, put forward the idea that alkaline hydrothermal vents, which release hydrogen, hydrogen sulfide, and methane, might have supplied the perfect conditions for the creation of simple organic molecules.
Although the circumstances surrounding hydrothermal vents are considered extremely harsh – they can reach temperatures as high as 400°C (752°F), there are microorganisms that thrive in these environments by using chemosynthesis.
Chemosynthesis is a biological process utilized by certain microbes to produce their own sustenance. Instead of using energy from sunlight, they harness the energy generated by chemical reactions. This innovative method enables these organisms to thrive in environments devoid of light, such as the Earth’s ocean floor.
4. The RNA world
The RNA world hypothesis suggests that prior to the existence of DNA and proteins, life on Earth was founded on a versatile molecule: RNA (ribonucleic acid).
DNA (deoxyribonucleic acid) allows organisms to develop, survive and reproduce and. DNA sequences are converted into messages, or instructions, that enable the production of proteins — complex molecules that are responsible for almost everything that happens in our bodies — and keeps us alive.
RNA, in contrast, fulfils these two vital roles for life: It retains genetic information and functions as a catalyst for critical chemical reactions.
In the 1980s, chemists Thomas Cech and Sidney Altman discovered RNA molecules with enzymatic capabilities, and they were awarded the Nobel Prize.
Scientists have theorized that RNA molecules which could replicate themselves and facilitate basic chemical reactions preceded the emergence of present-day living organisms. These RNA molecules, known as ribozymes, were likely gradually replaced by proteins which, due to their higher catalytic efficiency, became more favorable as catalysts.
There are several theories about the emergence of life, but the following have garnered the most attention from the scientific community.
Researchers worldwide, including those at Cardiff University, emphasize the intricacy of the question that remains a topic of both interest and fascination for us today.
Edited by: Zulfikar Abbany
Primary source:
Complex life on Earth originated approximately 3.5 billion years ago, rather than 2 billion years ago as previously believed, a recent study conducted by Cardiff University concludes, 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
