The oldest organism on Earth is often considered to be a type of marine organism known as Pando, a clonal colony of quaking aspen trees (Populus tremuloides) located in Utah, USA. This organism is estimated to be around 80,000 years old, with some estimates suggesting it could be even older. Each tree in the colony is genetically identical and shares a single root system, allowing this ancient organism to survive for such a long period.
Another contender for the title is the Great Barrier Reef in Australia, which is composed of many coral colonies, some of which can be thousands of years old. However, the reef itself as a structure is much older, dating back to around 500,000 years.
For single-celled organisms, cyanobacteria are among the oldest living organisms, with fossils dating back approximately 3.5 billion years. These microorganisms have played a crucial role in shaping Earth’s atmosphere by producing oxygen through photosynthesis.
Ultimately, determining the ‘oldest’ organism can depend on various interpretations, such as whether one considers individual members, clonal colonies, or the longevity of a species. Nevertheless, Pando is frequently highlighted as a remarkable example of longevity among living organisms.