Crystal eye ancient animals are certainly interesting. These ancient animals, namely Trilobites, have crystal eyes made of the mineral calcite. Trilobite itself is one of the ancient hard-shelled animals that lived during the Paleozoic.
The Paleozoic is a geological time that began 541 million years ago with the Cambrian explosion. The Paleozoic Era ended approximately 251.9 years ago and is divided into six epochs. The six ages are Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
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Trilobites are marine invertebrates that belong to the phylum Arthropoda. They are insects, centipedes, spiders and horseshoe crabs which are close relatives. Trilobites lived by crawling on the ocean floor, but some could swim.
Trilobite Crystal Eye Primordial Animal
During the Cambrian explosion, the Trilobite population grew so rapidly that they even dominated the Earth. At the beginning of its life, there are no crustaceans or jawed fish. In addition, there were no other threatening predators, making the Trilobites very abundant.
Trilobites alone have about 22,000 species of varying sizes. The smallest species is Bynumina Lirae which is only one millimeter in size. Meanwhile, the largest Trilobite species, Isotelus Rex, has a length of up to 72 cm.
Trilobites can be identified from their anatomical shape which has three segments or lobes. The three lobes are oriented lengthwise from the head to the tail. The lobe in the middle is the axical lobe and on either side are the pleural lobes.
The pleural lobes on the right and left of this ancient animal crystal eye are shaped like ribs. Then the main part of the body is protected by a hard and symmetrical shell. So Trilobites have three parts, namely the head or cephalon, the main body or thorax and the tail or pygidium.
Extinction of Trilobites
Trilobites have survived through the ages and have survived for nearly 300 million years. They became completely extinct 250 million years ago during the third mass extinction period. This period was the biggest extinction on earth because almost 90% of species became extinct.
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However, it is still uncertain what caused the mass extinction of The Permian-Triassic Extinction. Several hypotheses concluded that the cause was due to the impact of an asteroid impact, volcanic eruption or the spread of toxic gases. In addition, because of the evolution of jawed fish like sharks.
Trilobites, Crystal Eye Primordial Animals from Calcite
Trilobites had eyes made of hard crystals, a mineral known as calcite. This was revealed from the examination of the lens of the eye by the researchers. They found a damaged but well-fossilized eyepiece of a Trilobite composed of calcite.
However, researchers do not yet know the cause of the appearance of crystals in Trilobites’ eyes. There are also studies that question whether calcite eyes are the result of a preservation or fossilization process. Meanwhile, scientists studying Trilobites’ eyes can also predict how they work.
Trilobites may not be able to see at high resolution, but they are very sensitive to motion. Interestingly, this ancient animal also has compound eyes, just like insects. Each eye also consists of a collection of photoreceptor units or ommatidia with their respective lenses.
Trilobite Eye Types
Ancient animal Trilobite crystal eyes have a type of eye similar to modern insect eyes, namely holochroal. The eye has tiny photoreceptors covered by a single corneal membrane. These findings led scientists to believe that the workings of the eyes of Trilobites and insects were the same.
In insects, each ommatidia or photoreceptor unit will work independently. So that the insect will see the shadow in the form of a mosaic from the combination of all the shadows. Apart from the holochroal, there is another type of Trilobite eye, namely the abathochroal which belongs to Eodiscidae, the Trilobite family.
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This eye has a very small lens and is covered by a thin cornea. Finally, there is the schizochroal type which is an eye belonging to the Pacopida sub-order. These eyes have larger lenses, are farther apart and have individual corneas.
Thus the discussion about Trilobites, ancient crystal eye animals that are very interesting. With this discussion we can understand what kind of animal Trilobites are. We even know about their lifetime and also their extinction. (R10/HR-Online)
2023-07-15 14:36:20
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