Showing posts with label Cambrian.. Show all posts
Showing posts with label Cambrian.. Show all posts


Neither the science fiction writer Isaac Asimov, was as rare as this animal had happened. Get the name of Hallucigenia, a marvel of evolution. Its name refers to the word "hallucination", which is what they believed passing the first to see it, as this seems strange prehistoric animal that has been designed by a crazy artist, or an elephant or a dolphin. The paleontologists who discovered not believe what they saw, in fact, did not know its classification; if it was a plant, if it was face up or face down, did not know if he had head and where it was.

They were hallucinated when they found this impossibly small animal that was no more than 4 cm in length and that's apparitions in the Cambrian explosion, when there was the proliferation of life forms, some as strange as this.

As its body is tubular in shape, it is not easy to distinguish, in what place is the head. In fact, experts believe that the head is one of the bulky and ends with two appendices, but it's an assumption that an idea based on a test-out there.

Sensing where the head came next question was: how do walking? And still do not have the solution, after 40 years and several fossilized specimens found. The Hallucigenia had several protrusions. On the one hand, had 7 hard spines, and at first experts thought that moved like sea urchins .... moving the thorns. Then it found that he also had a soft tentacles moving in the opposite area .... how moving it? With the spikes or tentacles? Well, although it seems that the latter is more accepted, do not become totally agree ... and I do not know what to say.I will however get wet at the risk of saying the wrong thing (as you know, ignorance is very bold) If you walk with the tentacles, these could get food and on the other hand, the spines serve them to fend off potential predators. If it walk with barbed tentacles would not do them much good, much less as a defense. Therefore, to put right the Hallucigenia would say his feet were moving tentacles.

To give you a better idea of ​​the confusion brought about by the discovery of this animal, you even now some paleontologists think that it is an animal, but part of an even larger animal.
With what the story is a bit more complicated.

Anyway, if any of us, or our children, we traveled back in time to the Cambrian; Earth that we know seem another planet in another system, another galaxy and other different physical laws .... at least.


The Pikaia beings is one of the most important and that we should highlight, if we get an overall idea of ​​the exciting topic of evolution and prehistoric animals, I mean ...

Cambrian, 540 million years ago, at the beginning of the explosion of life that happened and all the various forms that appeared in the ancient seas. Appears then a small might just measuring 2 in (5 cm) long.  We're talking Pikaia.

This little creature would become the source of one of the major groups of animals to would be more successful throughout the history of Earth and ... where we also are included: vertebrates.

Lions, hyenas, falcons, whales, sharks, Allosaurus, Triceratops, Sabertooth, armored fish, gorillas and we owe our existence to this small, first vertebrate. We all come from it and was its advantageous morphology characteristic of vertebrates, which helped them survive, although it was a small animal compared to others of his time.

Well, Pikaia was not a colossus  or an apex predator in fact measured about 2 in (5 cm) long.

His body was flattened, hydrodynamic, which used to navigate near the ground where it fed, probably, filtering water particles.
Most characteristic of this small, prehistoric fish was that, unlike molluscs, which are invertebrates and some shelled, and arthropods with exoskeletons, the pikaia possessed the notochord, which is considered the evolutionary precursor of the column spine in all vertebrates.

This feature provided a fast, elasticity, speed with no other animals. Thanks to this feature, so it survived and was able to escape predators. Because the evolutionary experiment went well and that the Pikaia survived ... we are here.

Walking cactus (Diania cactiformis)

Today we are going to go back in time, we will go to the origin of complex life, until 520 million years ago when the first groups of animals (arthropods, mammals and molluscs) appeared on Earth.
In ancient seas, in the emergence of complex life (Cambrian Explosion) we find a rare animal, a creature that looks like a sketch of the creation ... as if evolution had thought - I'm going to put this together with this, to see what happens.
This prehistoric animal that seems from another planet, called Diania cactiformis, cactiformis means in the form of cactus, so its common name: The walking cactus.
The truth is that there is no plant. The experts believe that this curious animal occupies a far evolutionary empty, It is between worms and arthropods. With the discovery of this animal is evidence that the big group of arthropods evolved from worms. Among arthropods and worms, is walking cactus. Among the prehistoric arthropods more "famous" can find the Arthopleura, the Hurdia Victoria, the Anomalocaris or pulmonoscopius ... and now, the walking cactus, which is the oldest arthropod found yet.

The Diania cactiformis was small, measuring about 6 cm long and had a long, thin body, vermiform (worm-shaped elongated). His body was segmented with hard covering (exoskeleton), and body of arthropod born 10 pairs of spiny legs hard, sharp and thorny (hence the name of cactus). And you do not think it was like a starfish elongated, no. The walking cactus had jointed legs, was fast, and even experts think that could jump with some agility: he was a ruthless predator ... maybe I exaggerated when using the word "ruthless".

Anyway, walking cactus, it was a prehistoric ocean that lived 520 million years. It lived on the seabed of what is now the province of Yunnan in the Himalayas. Its marine fossils found in the higher mountain formation of the Earth. Another curious fact of which I speak.

A bit of prehistory.

Everyone knows the prehistory of the mind in which the dinosaurs disappeared about 65 million years. But few people know another story even more fascinating and more importance for what is life on land, but especially and more specifically, to us humans. It was not an isolated event but a chain of events, a struggle between forces of evolution among prehistoric creatures that ended with one victor, our ancestor ......... The story begins:

500 million years ago.

So far life in the prehistoric seas, oceans before the beginning of the Cambrian period,
consisted of single-celled or multicellular creatures (many
cells, but all the same) soft body, which they obtained their food by filtering the water around them, or feeding on bacterial mats (dense colonies of bacteria) on the ocean floor.

I will not go into details but then gave a very important place, which is known as the Cambrian Explosion, say it is from this date (500 thousand years) when the three-edged mother will result in all other species we know and that interaction
between them, set up, the situation now is the arthropods, molluscs and vertebrates (the group we belong to).

Well, at that time, life beyond the seas was unknown, and the seas and oceans were then inhabited by beings of strange shapes as the famous trilobites and other less friendly as Anomalocaris (left) or Hurdia Victoria (the latter were the top predators of the time). These three species were among the arthropods. The dominant and most numerous group that reigned on molluscs (its variety was insignificant) and vertebrates.

In fact, the Cambrian vertebrates were a small and unimportant. For example, while Victoria Hurdia reach 50 cm or up to one meter Anomalocaris, the

representative of the larger vertebrates that was Pikaia (pictured right) did not exceed 5 cm
length. Come on, that our ancestor was a true miniature land of giants.

The pikaia our ancestor, was long, small, light having a backbone instead of shell but it was also the major arthropod prey. He devoted himself to hide in the care of arthropods and eat the waste and the remains of prey left by large predators battleships were mainly scavengers.

Nothing seemed likely to change, the arthropods dominate the land and seas over the millennia, eating and leaving decimated vertebrates, thus reducing the possibility of not only our species but also birds, dinosaurs, fish and other mammals, may appear in the future. But conditions changed.

450 million years ago.

In the late Ordovician period (the next to the Cambrian period) was the second largest extinction of life on Earth history, eliminating 85% of the species.

A global ice age that froze oceans and seas

covered them with a blanket of 800 meters of ice and snow had catastrophic consequences for the life of this era. The lack of light and the intense cold was killing larger species and more specialized, bone arthropods. This led to the other two groups (vertebrates and molluscs) may develop: vertebrates evolved and appeared larger scavengers such as conodont (about 10 cm, right image). But they were vertebrates which rose to the position of the dominant group, but molluscs. The supremacy of vertebrates was cut again, but in this case by the large mollusks.

Now the predators were large molluscs such as Ortocono (left)

and Nautiloidea. And they dominated the other groups until they took another step, one giant leap in the way of the evolution of arthropods came ashore.

On land they had no predators, and eventually took the opportunity to grow and multiply. There were big and strong and the seas again to reconquer. And they succeeded. Arthropods were Jaekelopterus rhenaniae most important ancestors of scorpions and giant like Pulmonoscorpius.

Over time, the move gave them the advantage on mollusks to arthropods and vertebrates (leaving ground) would also be a fatal mistake that would destroy them.

375 million years ago.

Gradually, over the millennia, vertebrates were going to land, a land that was populated with a number of plants that helps to oxygenate the atmosphere and produced the right conditions for our ancestors to develop.

Shellfish centuries ago who had returned to background. In contrast, on land, vertebrates were developed only arthropods and began to exceed the size, strength or agility of the arthropods. The last battle was about to begin.

On the one hand were the arthropods were strong but had a weakness: its outer armor. They had to grow as the animal grew. If the animal was too big armor, and thus increasing the animal's weight. Could weigh as much that came a moment that was counterproductive in an evolutionary sense. At best, could reach a size of 3 meters.

On the other side were the vertebrate ancestors. Animals that could grow larger without becoming too heavy to be sustained. Vertebrates, thanks to its design, its backbone, they could better adapt, develop better, evolve ... and all this without becoming heavy tanks.

250 million years ago.

The reign of the arthropods are gone forever. And with this came the dinosaurs, birds, fish ... y.

.. us HUMANS.

Hurdia Victoria.

The further back in time, the prehistoric animals are rare, most unique and peculiar to our eyes. First adjustments, tests and experiments of evolution that is distributed andbranches, people still just a piece of a twig of the tree .... or less.500 million years ago during the Cambrian, appeared in the seas and oceans a trulystrange, like a squid but with teeth, larger body and gills was easier to pick up oxygen from the water and move faster. This is the Hurdia Victoria. Anomalocaris close relative to similar in many respects.

The Hurdia Victoria was a top predator of its time, ate many species with basic anatomical models and dominated the seas and oceans and the creatures of their time. Keep in mind that during his appearance was the Cambrian Explosion and manynew species were appearing and taking their first steps on dangerous waters and old.
And how was the Hurdia Victoria? Well, this prehistoric animal that is considered an ancestor of the arthropods, the large group that includes insects, crustaceans, spiders,millipedes and Chilopoda; could measure about 50 cm, which is giant compared tomost animals at the time.

His head had a couple of thorny claws (appendices), which helped carry food to hismouth, like a slice of pineapple. He had a hole in the pointy bump on the front of hishead, although the function of this organ remains unknown, since no protection couldhave been because there is underlying soft tissue. He lobes along the sides of the trunk, which were suspended large gills.

Predator and scavenger (supposedly) is considered by experts as the TyrannosaurusRex of the Cambrian.


During the Cambrian explosion of life (for about 525-510 millions years. Up to this point had not been very successful multicellular life) appeared the first predator to bite, was the Anomalocaris. The biggest predator of the Cambrian seas. Measure up to 1 meter and its name means "strange shrimp."

Possibly it was given this name because when they discovered the fossils were so strange that they thought of three different animals.

It had a segmented body, such as some crustaceans and a current "arms" armed with thorns, compound eyes (with a very developed on their prey, but not entirely confirmed). The mouth was circular and had 32 overlapping layers (four large and 28 small) equipped with small barbs which failed serrated rings around a central opening. With his arms gripping the defenseless Pikaia or trilobites and pounding and crushing.

Like trilobites, the Anomalocaris was an arthropod, bony internal skeleton had not, this was a protection mechanism, a cuticle or exoskeleton made of chitin and proteins such as cuticulina.

Curiosity: A recently described a new species closely related to Cambrian Anomalocaris the Hurdia victoria.
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