(ORDO NEWS) — Life on Earth has existed for about 3.7 billion years (and according to some sources even 4.7 billion), but the life that we see now is very young by the standards of the history of our planet.
The thing is, it has changed over and over again. Species constantly replace each other due to changes in the average temperature on the planet, the composition of the atmosphere, as well as a number of other environmental conditions.
A striking example of this is the oxygen catastrophe, which was indirectly caused by the Moon. Essentially, any creature that walks on land, crawls, flies, or swims in water lives to adapt to a changing environment. If it succeeds in adapting, it evolves, otherwise it dies out.
But which species of living animals is the most ancient, that is, remains unchanged longer than the rest, and how old is he? We propose to deal with this further.
The oldest creature on earth
The title of the oldest living creature in 2010 was awarded to Triops cancriformis, better known as the tadpole shrimp.
Her age is not just respectable, it is fantastic. Fossils have shown that these crustacean creatures lived from the Triassic period, which lasted from 251.9 to 201.3 million years ago. It’s hard to believe, but tadpole shrimp appeared around the same time as the first dinosaurs, and maybe even earlier.
Triops cancriformis have a body shape that resembles a shovel, and this is not just. With their armored bodies, they dig holes in the bottom, in which they live. As some scientists laugh, the design of these shrimp is so good that it hasn’t changed in hundreds of millions of years.
But did shrimp really remain identical to their Triassic ancestors during all this time? Several studies have shown that Triops cancriformis has something in common with the iPhone. Yes Yes! These creatures also did not change their appearance, but evolved under the shell.
As a result, different types of them with the same “design” appeared at different times. As reported in the journal PeerJ, the age of tadpole shrimp in their current form is 25 million years, which is also not small. But according to another study published in PLOS One, these creatures are no more than 2.6 million years old.
The oldest fish in the world
As it turned out, tadpole shrimp are not at all familiar with dinosaurs, since they have never been seen, unlike their ancient ancestors. But what about other creatures? The most ancient and famous “living fossil” is considered to be a type of deep-sea fish called coelacanths.
Their fossils were first discovered in the early 19th century. Studies have shown that these fish became extinct 66 million years ago, that is, at the same time as the dinosaurs. According to new data, the extinction could be caused by the impact of two meteorites at once.
However, in 1938, off the southern coast of Africa, fishermen caught a live coelacanth. This means that fossil fish are even older than tadpole shrimp – their age is 400 million years.
However, not everything is so clear with them either. A study published in 2010 in the journal Marine Biology showed that the current coelacanth appeared 20-30 million years ago, despite the fact that they are very similar in appearance to their ancestors.
The same situation is with horseshoe crabs, whose ancestry goes back 480 million years. Modern horseshoe crabs, although very similar to their ancestors, are only 25 million years old, according to Molecular Phylogenetics and Evolution.
What is the average lifespan of animal species
It must be said that the decoding of the evolution of all modern animals has not yet been completed. It is possible that scientists will be able to find species that originated with dinosaurs, or at least caught them.
However, even such “stable” creatures as tadpole shrimp, coelacanths and horseshoe crabs change periodically. Therefore, scientists are skeptical about the likelihood that it will be possible to discover more ancient creatures than those already known.
But what is the average lifespan of species of living beings? As reported in the publication American Scientist, as a rule, species live from 500 thousand to 3 million years. After that, they either change or die out.
There are various reasons for species change. One of them is DNA mutations that are passed down from generation to generation and gradually accumulate.
In addition, two genetically similar species may mate, resulting in new hybrid species. Also, predators and prey compete with each other, animals from the same ecosystem that eat the same food, etc.
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