In a break from ophthalmology, we’ll review a TV show about the biology of early Earth.
In 2004, the PBS program NOVA premiered its episode chronicling the currently most accepted theories and proofs of how life on Earth began entitled NOVA program Origins of Life: How Life Began. Likening the time that our planet has existed as a 24-hour day. As the hours tick by, Earth made significant physical changes, but only about 10% of the time the planet has existed hosted life large enough to see, with humans coming on to the scene only within the day’s final 30 seconds (NOVA, 2004). Before life like ours could exist, seemingly countless events and biological changes needed to take place.
Though we have no solid proof of how life began on Earth, scientists have found two very important components to early life—the formation of amino acids and microbes that “eat” noxious gasses. For the first part of the equation, scientist Stephen Miller designed an experiment to simulate an environment with similar gasses and chemicals that could have been found on the planet billions of years ago. In mixing these chemicals and introducing electricity to represent lightning strikes, which would have been quite common for the era, Miller found that amino acids began to form after a few days. Amino acids are often referred to as the building blocks of life, as they combine to form proteins. Additionally, theories exist that state Earth may have been introduced to certain amino acids through rocks striking the planet from space.
Researcher Jennifer Blank built a cannon to simulate the force of a comet striking the planet to see if acids could survive the force and instead found that the shock changed them into peptides. In her 2002 paper Astrophysical and Astrochemical Insights into the Origin of Life, Blank notes that the natural conditions of that period would have killed off life before it could begin, so life would have had to burrow into rock forms and underwater to live (Ehrenfreund et al, 2002). This information directly coincides with the theory that the original single celled lifeforms began underwater and eventually evolved to settle onto dry land, through fossilized chemicals found in 3.8 billion year old rock samples.
Throughout the coasts and mountains of Australia to the rock formations of Greenland, scientists are extracting samples of prehistoric earth and dissecting them to discover clues to what life existed and when it lived. Though billions of years of weather has long destroyed the physical formations of fossils, scientists have tested the rock in Greenland for the chemical trademarks left by organisms. In iron-ore rich mountains, Australia has a hidden landscape of peaks and valleys that house fossilized groove created by organisms from ages ago. In the coastal waters of the continent’s mainland, stone-like growths from the ground pop up above the water. These natural structures are made from sticky bacterium trapping the elements and then growing outward toward the surface to repeat the growth cycle. It is believed that organisms like these are responsible for turning the once red planet to the blue and green one we know today.
This program is an excellent introduction of the origin of life on Earth. The NOVA episode caught my attention and broke down the concepts of early life in an understandable way which help me digest information that would have been much more difficult had it been written in “researchese”. Confidently, I can say that I have a better idea of the theories behind early life and would highly recommend this program for anyone who may not know much about the planet’s earliest lifeforms or those interested in the development of our planet since its inception.
Ehrenfreund, Pascale & Irvine, W & Becker, L & Blank, J & Brucato, J & Colangeli, Luigi & Derenne, Sylvie & Despois, D & Dutrey, A & Fraaije, H & Lazcano, Antonio & Owen, Tamara & Robert, F & International Space Science Institute ISSI-Team, an. (2002). Astrophysical and Astrochemical Insights into the Origin of Life. Reports on Progress in Physics. 65. 1427. 10.1088/0034-4885/65/10/202.
Harper, A. (Director), & McMaster, J. (Writer). (2004, September 28). Origins: How life began [Television series episode]. In N. deGrasse Tyson (Executive Producer), NOVA. Boston, MA: WGBH.