The Universe is considered to be about 14 billion years old, and the Earth is estimated to be 4 billion years old. Many species came and went, while some got extinct and some are endangered. So, it begs the question: Which is the oldest living species or the longest living species in the world?
1. Meaning of Species
Species, in terms of biology, is the basic unit of classification of living organisms, whether it be an animal or a plant. The color, hair, skin, shape of our hands and toes, weight and height, differ from other human beings. Yet all human beings are a part of one species known as homo sapiens, which is Latin for wise men. (See Can you have a pet squirrel?)
2. Human Species
It may come as a surprise to many, humans or homo sapiens aren’t the oldest living species. The modern human origin happened around 200 thousand years ago in Africa. Also, homo sapiens doesn’t include human apes that came before us, i.e., home erectus or upright men. These are extinct species that lived between 135 thousand to around about 2 million years ago. (See Why do cannibals eat humans?)
3. Oldest Living Species
Since humans aren’t the longest living species, there are species far older than humans, as discussed below:
- Horsetail, which is over 300 million years old is a plant that is found worldwide except in the Antarctic region. They were domination landing for more than 100 million years and used to be about a hundred feet tall. Nowadays, they are much smaller and are used as weeds and pests in some places. They are also utilized as food, wood polish, and medicine in several cultures.
- Nautilus, Jellyfish, etc. are believed to have possibly lived for approximately 500 million years old. Nautilus is recognized by the spiral in their bodies, and have not evolved much from their ancestors. They have a lifespan of about 15-20 years. A Jellyfish, on the other hand, can be over 500 million years old as per the fossils found & studied. They both are usually found in water bodies. (See What is Blobfish (Psychrolutes marcidus)?)
- Sponges & Ctenophores (Comb Jellies) are over 600 to 700 million years old. Initially, the sponge was believed to be the oldest, but now, Comb Jellies has taken the new spot.
- The species that takes the crown is Cyanobacteria. It is over two billion years old with undisputed evidence. They are almost the age of Earth. They are found in every terrestrial and aquatic habitat like the oceans, dump soil, desert rocks, etc. They are known for their bluish-green tint, especially the aquatic cyanobacteria.
4. Long Living Species
As impressive as the oldest living species are, with most reaching a billion years of age. There are also species that aren’t the oldest living species but have a long life. We start our list with aquatic beings like Bowhead shark, Greenland Shark, Geoduck Clam, Rougheye Rockfish, Tubeworm, Red Sea Urchin, Koi fish, Tortoise. A land inhabited, Tuatara, is also among the animal and plant species that live anywhere from over 100 years, extending up to 500 years. But that’s not all!
Black Corals found underwater are assumed to have a life expectancy of over 4000 years and a glass sponge can live up to 10 thousand years and more. But the champions of this list are Hydra and Immortal jellyfish, and Turritopsis dohrnii. These two are potentially immortal beings as found by scientists. They are expected to live and observe the end of humanity with their own eyes from under the water. (Also read Top 8 World’s Smallest Animals)