The Origin of Life on Earth

                             

 

At one point in life, it is quite plausible that one has pondered about the origin of life. However, it isn’t as likely that they have utilized the inquiry process and chased after their curiosity. How did organisms suddenly emerge on Earth 3.5 billion years ago (Choi, 2017) and how did the basic single-celled organisms evolve into complex life forms about 600 million years ago? This research report contains thorough explanations of selected scientifically-backed theories, as well as visual aids to further elaborate, for those who haven’t researched this. The origin of life on Earth isn’t confirmed, but many theories have been made, and this research will include the more plausible ones: the lightning strike theory, panspermia, the theory of special creation, the theory of primordial soup, and the hydrothermal vent theory.

The first theory is the lightning strike theory. This theory suggests that life on Earth may have been caused by one or more random bolts of lightning. Researchers say that the lightning strikes may have freed some phosphorus, which is essential for the formation of biomolecules (Reuters, 2021). Phosphorus makes up the phosphate double-helix backbone of DNA and RNA, hereditary material in living organisms (Hess, 2021). The trapped phosphorus may have been released from some meteorites that contained schreibersite - the water-soluble phosphorus mineral.

Next up we have panspermia, which is a notion that proposes that life didn’t originate from Earth, but instead, from elsewhere in space (Choi, 2016). As an illustration, perhaps primitive cells or the building blocks of life were brought here by Martian meteorites - rocks formed and ejected from Mars. That would make us originally Martians. This can be proven to be possible with an example involving tardigrades, which are microscopic eight-legged animals that are notably tough. They can survive cold temperatures as low as -272 degrees celsius (just above the absolute zero, which is approximately -273 degrees celsius) and killer radiation from the sun and from distant supernovae - which are powerful stellar explosions (Herkewitz and Hernandez, 2020). In late 2019, the Israeli spacecraft Beresheet crashed on the moon and spilled thousands of tardigrades, so they are potentially the start of life on the moon (Herkewitz and Hernandez, 2020). Conceivably, something similar happened to the first humans, letting them settle down in a more comfortable environment and regress into what we are now: fragile and soft creatures.

The third theory regarding the origin of life is the theory of special creation, and it’s quite popular. According to this theory, life was created by supernatural power. The bible states that the world was created in six days. On the first day, God made heaven and Earth. On the second, He separated the sky from the water. On the third day, He made dry land and plants. On the fourth, He made the sun, the moon, and the stars. On the fifth day, He made fish and birds. Finally, on the last day, he made land animals and human beings; the first man was Adam and the first woman was Eve. This theory is purely religious, not scientific, as researchers have not found evidence. (Mondal, 2014)

Penultimately, we have the well-known theory about the origin of life: the primordial soup theory. This idea came independently from Russian Scientist Alexander Oparin and English Geneticist John Haldane. This theory proclaims that life started from a “soup” of the mix of gas in the atmosphere and the energy from lightning strikes, resulting in amino acids spontaneously forming in oceans. It has been proven to be possible with the Miller-Urey experiment (Scoville, 2018b). The Oparin-Haldane theory was tested by Stanley Miller and Harold Urey. They combined atmosphere gases in amounts that the early atmosphere was thought to contain, simulated an ocean, and put constant electrical discharges (Rogers, 2016). As a result, they got organic compounds (e.g. amino acids). Even though this experiment proved that the hypothesis was possible, there was scientific skepticism; there weren't constant lightning strikes in real life back then. But this skepticism was countered: just because the actual process may have taken longer, doesn’t mean the lab experiment was impossible (Scoville, 2018b). Hence, the primordial soup theory is not only well-known but also valid.

Finally, we have the hydrothermal vents theory. To elaborate on this theory, we need to explain what hydrothermal vents are. Hydrothermal vents are structures in the bottom of the ocean that have extreme conditions - there are extreme heat and pressure around the vents, hence the “thermal” in the name (Scoville, 2018a). Authors of the new theory argue the environmental conditions in porous hydrothermal vents — where heated, mineral-laden seawater spews from cracks in the ocean crust — created a gradient in positively charged protons that served as a "battery" to fuel the creation of organic molecules and proto-cells (Ghose, 2013). Proto-cells are regarded as vital building blocks for life, so this supports the idea that life may have originated from hydrothermal vents (Cockburn, 2019). Later on, primitive cellular pumps gradually evolved the ability to use a different type of gradient — the difference in sodium particles inside and outside the cell — as a battery to power the construction of complex molecules like proteins (Ghose, 2013). But why does that matter? The previous description that was mentioned depicts perfect conditions for the origin of life (Baker, 2019). Archaea live and thrive in and near these vents (Scoville, 2018a). Since this Domain of life tends to be considered the most primitive of organisms, it is not a stretch to believe they were the first to populate the Earth (Scoville, 2018a). Conditions are just right in the hydrothermal vents to keep the Archaea alive and reproducing (Scoville, 2018a). With the amount of heat and pressure in these areas, along with the types of chemicals available, life can be created and changed relatively quickly (Scoville, 2018a). Scientists have also traced the DNA of all currently living organisms back to a common ancestor extremophile that would have been found in the hydrothermal vents (Scoville, 2018a). Not only that but some of the world’s oldest fossils, discovered by a UCL-led team, originated at such underwater vents (Cockburn, 2019).

In summation, there is an endless amount of theories, but the main potential ones featured in this research report are the lightning strike theory, panspermia, the theory of special creation, the theory of primordial soup, and the hydrothermal vent theory, respectively. The lightning strike theory states that some of the vital building blocks of life were delivered by lightning bolts. Panspermia is the notion that proposing that life came from elsewhere and was delivered by something (e.g. martian meteorites). The theory of special creation is more religious, and it states that life was created by supernatural power, specifically the power of God. The primordial soup theory, which is more popular, proclaims that a combination of atmosphere gas, water, and electric discharge might have resulted in organic compounds, hence life. Lastly, the hydrothermal vents theory suggests that life could’ve originated from hydrothermal vents. Hopefully, this research report helped answer the inquiry regarding the origin of life. There may be an infinite amount of possibilities of the origin of life, but listing and understanding the more plausible ones can do a big deal in helping us reach a solid conclusion, one step at a time.

Citations

Baker, Harry. “Hydrothermal Vents, Abiogenesis and Life in the Solar System.” Marine Madness, 12 Feb. 2019, marinemadness.blog/2019/02/12/hydrothermal-vents-abiogenesis-and-life-in-the-solar-system/.

Choi, Charles Q. “7 Theories on the Origin of Life.” LiveScience, Purch, 24 Mar. 2016, www.livescience.com/13363-7-theories-origin-life.html#:~:text=7%20Theories%20on%20the%20Origin%20of%20Life%201,was%20brought%20here%20from%20elsewhere%20in%20space.

Choi, Charles Q. “NASA Astrobiology.” Astrobiology at NASA, NASA, 13 Feb. 2017, https://astrobiology.nasa.gov/news/how-did-multicellular-life-evolve/.

Cockburn, Harry. “Life on Earth Probably Originated in Deep-Sea Vents and Aliens Could Be Growing the Same Way Now, Scientists Suggest.” The Independent, Independent Digital News and Media, 5 Nov. 2019, www.independent.co.uk/news/science/origin-life-deep-sea-theory-hydrothermal-vents-aliens-planets-oceans-a9185991.html.

Ghose, Tia. “Origin of Life: Did a Simple Pump Drive Process?” LiveScience, Purch, 10 Jan. 2013, www.livescience.com/26173-hydrothermal-vent-life-origins.html.

Herkewitz, William, and Daisy Hernandez. “The Secrets of the Only Animal That Can Survive in Space.” Popular Mechanics, Popular Mechanics, 21 Aug. 2020, www.popularmechanics.com/space/a11137/tardigrades-water-bears/.

Hess, Benjamin. “Origin of Life: Lightning Strikes May Have Provided Missing Ingredient for Earth's First Organisms.” Singularity Hub, Singularity Hub, 17 Mar. 2021, singularityhub.com/2021/03/17/origin-of-life-lightning-strikes-may-have-provided-missing-ingredient-for-earths-first-organisms/.

Mondal, Puja. “Origin of Life: 5 Ancient Theories of Origin of Life.” Your Article Library, Your Article Library, 22 Feb. 2014, www.yourarticlelibrary.com/biology/origin-of-life-5-ancient-theories-of-origin-of-life/13248.

Reuters, Thomson. “Lightning Strikes May Have Been Key to Origin of Life on Earth | CBC News.” CBCnews, CBC/Radio Canada, 17 Mar. 2021, www.cbc.ca/news/technology/lightning-origin-of-life-1.5952917.

Rogers, Kara. “Abiogenesis.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 26 Sept. 2016, www.britannica.com/science/abiogenesis.

Scoville, Heather. “Early Life Theories - Hydrothermal Vents.” ThoughtCo, ThoughtCo, 23 Jan. 2018a, www.thoughtco.com/early-life-theory-of-hydrothermal-vents-1224529.

Scoville, Heather. “Early Life Theories: Primordial Soup.” ThoughtCo, ThoughtCo, 5 Mar. 2018b, www.thoughtco.com/early-life-theory-of-primordial-soup-1224531.