Life on Earth has existed for about 3.7 billionyears (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 what kind of living animal is the most ancient, that is, it remains unchanged longer than the rest, and how old is it? We propose to deal with this further.
The oldest creature on earth
The title of the oldest living being in 2010было присвоено Triops cancriformis , больше известному как креветка-головастик. Ее возраст не просто почтенный, он фантастический. Окаменелости показали, что эти ракообразные существа жили с триасового периода, который длился с 251,9 до 201,3 миллиона лет назад. В это сложно поверить, но креветки-головастики появились примерно тогда же, когда и первые динозавры, а может и еще раньше.
Triops cancriformis имеют форму туловища, resembling 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 is it really for all this timedid shrimp remain identical to their Triassic ancestors? 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 allare familiar with dinosaurs, as 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, fishermencaught 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 with horseshoe crabs, pedigreewhich is 480 million years old. 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 allmodern animals is not finished yet. 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 speciesLiving creatures? 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.
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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.