The mysterious origins of life on Earth - Luka Seamus Wright
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The first person to really explore the origin of life was Francesco Redi. In the 17thh century he experimentally proved that maggots did not spontaneously generate in rotting meat. This experiment was the first to reject the idea of spontaneous generation of life. Today, scientists are applying the concepts, tools and questions, used to understand the origin of life on Earth, in order to find life in the extraterrestrial universe
If “all life emerged from an egg”, as Francesco Redi put it, where lies the true origin of life? This question inspires many scientists to this day. In the late 19th century, the British naturalist Charles Darwin envisioned “some warm little pond” as the place where life originated.
In the early 20th century, J.B.S. Haldane and Alexander Oparin independently developed the hypothesis that life originated in a primordial soup enveloped by an atmosphere rich in methane and ammonia. This became known as the Oparin-Haldane hypothesis and was empirically tested by Harold Urey and his student Stanley Miller. The Miller-Urey experiment proved that organic compounds could be generated from inorganic substances with the help of electric sparks. However, the problem with this experiment is that the primordial atmosphere was like ours today, just with a lot more carbon dioxide and no oxygen.
The chemical compounds necessary to life needed to be derived from somewhere other than the atmosphere. In addition, it was suggested that volcanic eruptions and UV radiation made it impossible for life to form on the Earth’s surface. But it was also clear that the first living organism had to be an autotroph like plants, which are only found in sunlight.
These two seemingly contradicting requirements for the origin of life were resolved when, diving in the DSV Alvin, oceanographer Jack Corliss and his team discovered hydrothermal vents at the Galápagos Rift. These black smokers provided a chemical gradient that was harnessed by microbial autotrophs in a process called chemosynthesis.
Since their discovery in the 80s, many marine scientists have been studying deep sea hydrothermal vents. Notable scientists that pushed for the recognition of hydrothermal vents as the cradle of life include Günter Wächtershäuser, Robert Hazen, William Martin and Gretchen Früh-Green. The latter lead the discovery of Lost City and has since been at the forefront of studying this alkaline vent system.
Diversity at hydrothermal vents and why the deep sea needs protection
Hydrothermal vents are true biodiversity hotspots in the deep sea. Alkaline vents like Lost City were initially thought to be devoid of life, until its diverse microbial community was discovered. Black smokers boast a conspicuous array of fascinating animals. These include giant red tube worms called Riftia pachyptila, which rely entirely on symbiotic chemoautotrophic bacteria
for nourishment, white skates called Bathyraja spinosissima, which lay their eggs near black smokers, giant mussels called Bathymodiolus thermophilus, and white crabs in the family Bythograeidae.
The Lost City hydrothermal vent field was declared open to deep sea mining by the International Seabed Authority last year. Hydrothermal vents are considered to harbor high concentrations of precious minerals. With the globally increasing demand for smartphones, and the plethora of rare minerals contained within them, investors are looking for new ways to acquire these resources in large quantities. Many other devices, considered to be part of modern everyday life, like computers and electric cars, require rare elements as well. This high demand is driving the development of deep sea mining rovers and we can expect mining operations targeted at the Earth’s largest ecosystem in the near future.
Mining is not the only human impact on the deep sea. Deep sea fishing is thought to have tremendous impacts because trawling destroys a wide range of benthic habitats. Most notoriously, the orange roughy (Hoplostethus atlanticus) is fished on a large scale. Ironically, the fishery exploiting the orange roughy, which is listed on the IUCN endangered species list, was recently certified as sustainable by the Marine Stewardship Council.
With a globally increasing need for oil and gas, deepwater drilling is becoming increasingly common, with known consequences. Many nations have been trying to extend their deep sea territory through existing laws and loopholes, in order to claim more resources. The most famous example is the “Arctic resources race”. With adequate foresight and by planning conservation strategies it is possible to manage these natural resources in the deep sea.
Unfortunately, the current money-driven race for the exploitation of the deep sea is lacking required planning and conservation policy. However, many marine scientists are striving to discover much that yet lies in the unknown depths of the ocean. Do we want to lose these fascinating and mysterious ecosystems before we can even attempt to fully understand them?
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