In 1859, the British biologist Charles Robert Darwin proposed the theory that shocked the world - evolution - in the book "The Origin of Species". That is, all living things on Earth evolved from a small number of common ancestors after a long period of natural selection.
You know, at that time, people's cognition was still stuck in "creationism", believing that God created everything, including life. So imagine what a sensation evolution caused in its time.
After hundreds of years of development and improvement, the theory of evolution has become the cornerstone of the field of biology, and on this basis, the "modern comprehensive evolution theory" has been derived, and human understanding of the biological world has been further integrated and sublimated.
However, not everyone agrees with the view of evolution, for example, many people have asked that if evolution is really correct, then why do some organisms not continue to evolve for hundreds of millions of years, but have become what we call "living fossils"?
<h1 class="pgc-h-arrow-right" data-track="11" > organisms never stopped evolving</h1>
In fact, this question is incorrect or inaccurate, and before exploring the answer, we must first know two facts: First, the creatures called "living fossils" are actually evolving all the time, and they are not exactly the same as the "ancestors" of tens of millions or hundreds of millions of years.
Second, some creatures with a long history are still living a moist life, such as cockroaches, crocodiles, sharks, and so on.
Don't look at some creatures that look almost exactly the same as their "ancestors", but the same may only be part of the appearance, if you really put it together with the "ancestors", there may be reproductive isolation between the two.
Under the invasion of the torrent of time, the earth's environment has changed dramatically compared with hundreds of millions of years ago, so whether it is the demand for the environment or the basic physiological indicators, there must have been some changes between living fossil species and ancestors, otherwise they have no way to continue to this day.
According to fossil evidence, the earliest sharks appeared in the Silurian Period 420 million years ago, they felt the warmth of the sun earlier than the dinosaurs, and the youngest shark in the shark family was the bamboo shark that appeared more than 3 million years ago, which was small and only about 1 meter long.
There are currently more than 500 shark species in existence, which vary in size and are distributed in all ecological niches in the ocean. Due to the large differences in morphology, many species of sharks are not considered sharks at all. For example, many people recognize the largest whale shark as a whale and the flat form of angel shark for a ray.
From the shark example, it can be seen that the primitive and historical structure of the body is not actually a key factor in becoming a "living fossil". If there is a chance, no creature will give up racial continuation, and then actively adjust itself to the environment.
<h1 class="pgc-h-arrow-right" data-track="28" > the "living fossils" of the Thin West Mountain</h1>
So why don't other living fossil creatures "thrive" like sharks? In fact, behind this problem is a lamentable fact: living fossils without prosperity are slowly dying.
It is precisely because they have no place to stay, so they will now guard the only acre and three points of land, but even then it is difficult to stop them from dying, and the pressure given by other creatures is constantly encroaching on the living space and ecological niche of living fossils.
Let's take, for example, the somewhat intimidating-looking horseshoe crab (hòu), which is a very well-known living fossil species. Studies have shown that the earliest horseshoe crabs appeared in the Devonian Period 400 million years ago and once bathed in the same sunlight as dinosaurs, but only 4 species remain.
Fossil evidence shows that the 140 million-year-old Darwin's horseshoe crab and the current American horseshoe crab have no difference in appearance, while 140 million years ago the horseshoe crab family was very prosperous, with many more exotic-looking branches, indicating that the species also had a golden age.
Unfortunately, these branches have not resisted environmental pressures and have disappeared into the torrent of history, leaving only a few species now, which is evidence of decline and demise.
In the process of competing for niches with other species, the horseshoe crab was defeated by the more dominant species and had to retreat to the ecological niches it had already occupied.
From the example of horseshoe crabs, it can be found that it is not that they do not want to continue to evolve, but that they cannot find a place in the ecosystem after evolution, so they have become "living fossils" so far.
A similar example is the ginkgo tree, which is known as a living fossil of the plant kingdom. Theoretically, this 245 million-year-old plant should have soon withdrawn from the stage of history, and they were only a few single plants distributed near Tianmu Mountain, but because of their unique trunk texture and leaves, humans used them as scenic plants, which saved the precarious ginkgo trees and allowed them to re-flourish on the earth.
summary
In general, organisms will become "living fossils" with almost no changes in hundreds of millions of years, and cannot become a "weapon" to refute evolution, but the existence of such a situation can perfectly reflect the correctness of evolution and its core content - natural selection.