Is there any evolutionary reason for ( some of us ) vertebrates to have eye color?

The Meakers / mēk·ərs / The Bright Yellow Turbinete Sp: Cerebraocula Clarusxantho-Miratorpod “ Bright Yellow-Fan Feet with Skull Eye “ 2½ feet long ( tip of nose to the ends of propeller feet ) & 1¾ feet wide ( wingspan of median fins )

Gliding low to the ground of any bed of blue meadows, known as Psammoids, are also found plentiful in nearly every aquatic ecosystem, are the Meakers. Meakers belong to a highly wide-ranging clade of under-water creatures that originated the lineage of Betapods, a biodiverse group of terrestrial creatures on Baron that include the likes of the Tortoise Mole.

This Superclass of organisms are widely known as Turbinetes casually and scientifically referred to as Machinapisca or “ Machine Fish “, which usually derives from how they appear more synthetic than a natural organism, and also to a especially evolved ability of the Turbinete. On most fully-aquatic clades of Turbinetes, they carry a very old, specialized style of water propulsion, which undergoes several steps and adaptations to be accomplished.

First, within the 3rd pair of spiracles on the side of the body. This pair takes large quantities of water into itself, taking all of the oxygen it can from it, and if this were to be the 1st or 2nd pair of spiracles, that’s where it would usually end.

However, The water instead of being pushed right back out is channeled through with a combination of several muscles and air ( which is far denser here on Baron compared to Earth air ) that are kept in internal bladders, they push water in the last pair of spiracles at the end of the body.

These last pair of spiracles aren't seen easily, especially in the Meaker, and don't actually perform any sorts of respiratory function either. Instead they make another push with hydraulic tendons, sending it out of the body at extraordinary speeds.

Finally, this is where the fins come in. Held very abnormally, almost bent at a right angle, are held right outside a thin construct of bone that acts against friction from the water current. These limbs are very flexible at the joint to its body, near where glands reside that release hydrophobic grease. They use this grease to act against the high friction, for the fins turn extraordinarily fast, spinning on an orbital socket that creates an almost hemispherical movement. Which harmonically used in sync, can control the exact direction of where the water is propelled to.

In the majority of species, this system is very energy demanding to be performed swiftly, and used to get out of a sticky situation very quickly. The family of Meakers actually have a more creative technique for their propulsion system. Contrary to other non-Meaker Turbinetes, their 3rd spiracle pair is greatly enlarged, which aids in swallowing a great volume of water. All of this water gets spued back in a very strong fashion out to the back where the Fins are used like fans, blowing it all away. This extreme function and the way the propeller feet are designed, this does not contribute much to propulsion speed wise anyhow. Instead, the massive intake of water is conducted to drag the flow of Psammoidic grasses and reveal whatever may be hiding within its filaments. This unique form of predation allows the Meaker to hunt down a variety of crustacean-like aliens that are too small to be noticed by other hunters. And since the threaded grasses conceal detection via echolocative means, the Meaker has a well developed oculus on its head, not true eyes though as they're only very primitive cells and tissues that pierce through the plated head. These cells and tissues can't visualize color, but see thermal radiation emitting off of decently warm organisms. And by manipulating water currents and the Plasmoids tissues, they can rip off the colder blanket of filaments that covers up their prey's thermal readings.

This hunting strategy is mighty effective for competing for food, but this comes back with a heavy drawback. Gliding adjacent to Psammoids doesn't come risk free, as Psammoids dissolve deposits and release deadly toxic compounds as a byproduct, and living near those areas for too long can result in lethal short term and long term effects. To combat this, the Meaker attempts its best to stray from the shallows for long periods of time when there satiated. Only returning back when in need of food or possible shelter. Even with this, keep in mind that the accelerated pull of water into its lungs driven by the propulsion system will increase the rate of the chemicals threatening effects.

The way this creature tries its darndest to fend off is simply having extremely well suited immune systems in its respiratory system. The way the immune system fights the foreign substances is quite interesting. Instead of killing them, they trap them in a sticky microscopic protein and carry them into the lining of the GI tract, as the effects of the toxin only affect the repertory and nervous system. This feature is actually quite useful as it kills harmful microscopic parasites that hide within the intestines and leach of the Meaker and also adds the benefit of making its digestive tract virtually inedible to creatures that hunt the Meaker. This is because if a hunter tries to eat this guy, and they unveil the digestive tract which then becomes exposed to warm water, the compounds expand and expel which engulf whatever creature was trying to get a simple meal. To display a pattern of thought that lets most predators know that the Meaker isn't on the menu, Meakers display bright yellow, orange, & green colors to stand out as the clearly lethal treat they are.

/r/SpeculativeEvolution Thread