Manta Ray:  Defying Evolutionary pattern

Manta Ray: Defying Evolutionary pattern

For a long time, one of my favorite creatures in the ocean has been the Manta Ray. The Manta Ray is the largest of the rays, and is one of the most unique creatures in the oceans. A cartilaginous fish, the Manta Ray is a serious challenge to evolutionary theory. In this article, I’ll introduce you to the Manta Ray, and why they pose a challenge to evolutionary theory.

The Manta Ray is actually two separate species of manta ray.  The larger of the two species, Manta birostris can be as wide as twenty-three feet and weigh over two tons.  They are noted for their horn like projections in front of their surprisingly wide mouths. It is unknown exactly how long they live, with estimates ranging from fifty to one hundred years.  Mantas are designed to eat plankton, filtering it out of the water with specially designed gill arches.  They migrate throughout the worlds oceans, often appearing at the same place at the same time every year, following the movement of the plankton.  They are believed to reach reproductive age somewhere between ages ten and fifteen. They have a gestation period of around one year and give birth to live young, ovoviviparously.  Essentially that means they lay eggs which hatch internally and then are born.  They give birth to one, sometimes two pups.  Manta’s skin is covered in mucous, which is thought to protect against parasites.  They have the largest brain of all fish yet, unlike their fellow rays, lack the venomous spine on their tail.  They do have teeth, but only in the lower jaw, which are used for grinding up food, and in mating. Natural predators of the Manta include killer whales and large sharks such as Great Whites.

Evolutionists have proposed that sharks and rays evolved from the same common ancestor since both are cartilaginous fishes. The path of Manta Ray evolution is believed to have diverged from the smaller, bottom dwelling rays approximately twenty million years ago. The two species of Manta Ray supposedly diverged around the same time that man and Neanderthal man diverged.  There are very few fossilized rays, likely due to the fact that cartilage has a much harder time fossilizing than bone. This makes establishing a true fossil tree of life almost impossible without extreme amounts of speculation.

However, the Manta Ray actually defies the evolutionary thought process regarding the evolution of rays and sharks. Here is why.  The first problem is the massive difference between Manta Rays and normal rays.  Normal rays have a flattened body, with mouths on the underside, meant for picking food out of the seabed. The Manta Ray has a mouth on the front of the body, meant for gulping food while swimming.  Most, not all rays, are semi-rounded in shape. The Manta Ray has a distinct wing shape.  Most rays are a mere few feet in size and a no more than a foot in width.  The Manta Rays dwarf them.  Rays are defined by the venomous spine that sits on their tail. One species of Manta completely lacks a spine, while the other has a non-venomous spine. Rays have small brains relative to their size. Mantas have the largest brain of all fishes. Rays are almost exclusively bottom dwellers. Mantas are open water travelers.  The second issue is that the Manta Ray defies natural selection.  Natural selection is supposed to select for things that are advantageous for the for the organism. Why then, would natural selection select against a defensive mechanism when there are still predators to contend with? Surely the offspring with the defensive mechanism would have been selected for, rather than against.

Another issue, perhaps the most damaging in fact, is a specialized system called the rete mirabile. The rete mirabile essentially is a system of blood vessels formed in a net-like structure.  This  allows for the exchange of oxygen and heat between the brain and the bloodstream. Since Mantas have such large brains for fish, this is obviously a key component. It was made even more so by a study published recently, which claims that Mantas dive to some depth to catch small fish from schools. If this study is correct, the rete mirabile would be essential to keep the Manta’s brain warm and oxygenated, allowing it to process faster.  However, the supposed evolutionary ancestors of Manta’s, the rays, do not have rete mirabile.  How would evolutionists explain the development of rete mirabile in a ray?  Rays do not dive to the depths that Mantas do. Why would they develop rete mirabile for deep dives? And why would their small brains even need rete mirabile?  These are questions that evolutionists must answer.  As a side not, where are the transitional forms? Why do we not see any forms which even remotely resemble a transition?

Creationists have no problem with the Manta Ray. The rete mirabile would have been designed the way they are from the beginning.  Since Mantas would have been formed as their own separate kind, the difference between them and the normal rays is immaterial since they are not descended one from the other.  This would also explain the complete lack of transitional forms since there never would have been any in the first place.  Surely it would make much more sense to say that Manta’s were specially designed to work exactly how they do today, rather than saying that they blindly evolved over millions of years.

 

Harry

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