Numerous studies on crabs and the findings at the point of evolution open an indispensable door for examining these creatures in depth.
Let’s make a detailed introduction to the world of crabs, about which there are many question marks.
No living thing’s evolutionary process has astonished biologists as much as crabs.
With a study they conducted in 2021, researchers tried to unravel the evolutionary history of crabs in full detail, and it turned out that these creatures have actually evolved at least five times in the last 250 million years.
In a study published in a journal in 2017, porcelain crabs, king crabs, true crabs infraorder, coconut crabs and hairy stone crabs evolved independently into different forms.
In fact, the common ancestor of these creatures was a completely different species that did not look like a crab.
In 1916, a British biologist named the evolutionary tendency of these crab-like but non-crab-like forms “carcinization”, derived from the Greek word “carcinos” meaning crab.
The ancestors of these creatures, which did not resemble crab, had a very similar appearance by being exposed to the conditions such as temperature, gravity and time that real crabs were exposed to, and this situation began to be called crabization.
It has also been suggested that crabs are extraordinarily resilient creatures, leading to the regular selection of physical traits associated with this appearance in many species.
In addition to the external appearance, the neurological structure, circulatory system and many other organs and structures have evolved into completely similar structures.
On the basis of this, there is the shaping of some internal organs and structures in parallel with the external morphologies. Thus, features like these seen in creatures that have adapted to similar environments have led to the evolution of similar internal organ structures.
In this case, we can conclude that when one living thing evolves, the evolution of another is inevitable. In fact, evolution contains a much more predictable process than previously thought.
For example, king crabs are thought to have evolved directly from hermit crabs.
In fact, such an evolutionary change is not yet widely accepted among evolutionary biologists, but king crabs are thought to be an exception in this regard.
This is enough to show that the two crabs have a clear ancestor-descendant relationship, and the transformation of king crabs into hermit crabs thus explains the reason for the asymmetry encountered in crabs.
The species Alllopetrolisthes spinifrons, which is also one of the species that underwent carcinization and became a crab, did not only stay with its body form; it also evolved as a sexual andromorphic, with males having a shorter abdomen, as in true crabs.
There is another point that confuses them: Every living thing that you think is a crab by being deceived by its appearance is not actually a crab.
For example, mud crabs and swimming crabs are classified as “true” crabs; Those known as pointed kings or hermit crabs, which attract attention with their spiral bellies, fall into the false crabs category.
It is actually quite easy to distinguish whether crabs are a real crab or another creature that we think is a crab.
The most obvious difference between fake and real crabs is how many legs they have. Real crabs have five pairs of skinny legs. The first of these have been modified with a pair of grippers and are not used for movement. False crabs also have four legs, but a smaller pair on the back, unlike the others.
In addition to all this, a Harvard University analysis reveals surprising findings about crabs.
According to the study, both fake and real crabs; may have a broad, flat and hard shell. The curved tails, one of the most striking features of these creatures, can also be found in both species.
Also, Bracken-Grissom argues that having a crab-like shape would confer some kind of evolutionary advantage.
Currently, the findings and gains from the crab shape remain a mystery, but biologists think it will have an impact on the ability of new species to diversify and colonize new habitats.
Although it is thought that the crustaceans in the world have evolved into crabs, a final form has not been reached yet. At this point, we understand that despite the studies conducted by successful researchers for many years, there are many things that remain unknown about these creatures.
In fact, in the next million years, crab formation may lose its evolutionary popularity, and crustaceans may diverge from this shape, on the contrary.
The conclusion we have arrived at is that evolution is not as simple as one might think, and it still continues. It probably looks like it will continue to evolve and change forever.
It seems that it will remain a mystery why the crab-like forms of evolution continue to evolve continuously. No doubt, scientists will not stop researching and questioning. If evolution continues at this point, let’s say he knows something.
32594
