These ancient organisms have been around for millions, or ever billions of years and have achieved apparent perfection in their environment. Millennia have passed, and they keep on keeping on. Sure, a tail might shorten, an extra tentacle might grow, or they might develop a more streamlined coat of armor… but, like that guy you know with the haircut he’s had since high school, these animals have asked themselves the question: Why change it if it’s working?
These are the oldest living things on the planet, and they just might still be here long after we are nothing more than fossils found buried in a pile of styrofoam take-out boxes.
The oldest known cyanobacteria fossils were found on Archaean rocks of western Australia. Cyanobacteria, or blue-green algae, is a type of bacteria that uses photosynthesis to create energy. It is believed that this played a role in oxidizing the earth’s atmosphere, making the planet more suitable for life as we know it.
Sponges are from an ancient animal group whose lineage can be traced back to the beginnings of animal life. Fossils of glass sponges have been found in rocks in Australia, China, and Mongolia. Although about 90% of modern sponges are demosponges, fossilized remains of this type are less common than other types because their skeletons are composed of relatively soft spongin that does not fossilize well.
Jellyfish belong to the group of animals called Cnidaria or Coelenterata. This group includes corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans. They are hard to fossilize, as they’re made of mostly water, but fossils suggest they are even older than previously thought.
Horseshoe crabs are considered “living fossils.” The earliest horseshoe crab fossils are dated to the Ordovician period. These marine arthropods l ive primarily near shallow ocean waters with soft, sandy or muddy bottoms. Their populations have been in decline due to habitat destruction and over harvesting.
A rare order of fish, coelacanths are more closely related to lungfish, reptiles and even mammals than to common ray-finned fish. Live species have been discovered as recently as 1998.
The Ginkgo tree is the only living representative of the order Ginkgoales, a group of gymnosperms dating back to 270 million years ago in the Permian period. Due to geological cataclysms, only three or four species were left in the Tertiary period (65 million years ago). The extinction of the dinosaurs as potential seed dispersers of the tree’s large seeds may also have influenced this decline, which is in line with the fossil records.
Often called “living fossils,” the nautilus originated in the Late Triassic period, and is a marine mollusk. The name means “sailor” in Greek. The nautilus is only found in the Indo-Pacific Ocean. They live in the deep slopes of coral reefs.
This little guy has the distinction of being the oldest living species on earth that has existed UNCHANGED for 200 million years. In other words, he may not have been around as long as some of the creatures above him, but today he’s is still virtually indistinguishable from his 200 million year old fossil.
Sturgeon and related paddlefish have undergone remarkably little morphological change, indicating that their evolution has been slow and earning them informal status of “living fossils.” This is explained, in part, by their long inter-generation time, tolerance for wide ranges of water temperature and salinity, lack of predators due to size, and the abundance of prey items in their benthic environment.
The most primitive species of living ants, the DNA of the Martialis heureka (which roughly translates to “From Mars! Wow!”) has barely changed in the last 100 million years. This species was discovered in the Amazon in 2000, and generally lives its life underground.