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At first glance the coelacanth may seem as if it has almost not evolved at all since its prehistoric origins. This is evident from its close resemblance to the fossils and remains of coelacanths that are millions of years old. The evolution of the genes of the coelacanth has been very slow when compared to other fish and vertebrates. In fact, the coelacanth is believed to have the slowest evolving genome of all known vertebrates. One of the most notable features of this fish that is common to other fish from its time are its large and heavy scales.
For the most part, the coelacanth has not changed significantly over the course of time because it is well adapted to its environment and the environment in which it lives has not experienced much change. The deep-sea habitat has stayed in a fairly consistent state over the course of time. Another reason for few changes in the coelacanth is that they lack any major predators, which prompts little adaptations as well. In other words, this animal is almost at the optimum level of adaptation for its lifestyle and habitat. The virtual absence of pressure and tension from natural selection is one of the many theories behind this lack of evolution.
Studying the genome of the coelacanth has also had a
notable impact in terms of evolution of tetrapods. It has shown how
lungfish, not coelacanths, are the likely forerunners to tetrapods and
terrestrial vertebrates. The most important factor though is that
lungfish and coelacanths are closely related, so research on coelacanths
can shed light on aspects of lungfish.
The coelacanths alive in modern times do hold on to a large amount of features, but they have still evolved in certain ways since prehistoric times. One example of this is producing live young inside females, instead leaving eggs exposed to the open to hatch.
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