| Dove Cresswells Dog Training Online |
 | Positive, highly effective puppy and dog training by a professional trainer for film and television. Interesting visit for all pet lovers. Today we play with our pets, we see animals everywhere at home, in the park, and thorough mass communication media too. They are part of our everyday life. But life is an ever changing thing and means change and evolution; in ancient times, life on our planet was very different and more scarce, since we did not have the proliferation neither the variety of present-day life forms. If we could travel in time back 515 million years we would arrive in the Cambrian period, and we would see that the world was very different then, like if we were on another planet because not even the landmasses would be recognisable by us, not to mention the anima and vegetal species. We would find no life outside water, and there, only a few organisms would remind us of forms we know from the present. But it is at that period of time that our flora and fauna began to evolve rapidly, and so the way to our modern species was paved. It is known that complex life existed long before in our planet: the findings of the Ediacara fauna indicate us so, but all those beings found in the fossil record were either invertebrates or marine plants. Life originated on Earth about 3.350 million years ago as simple unicellular organisms; for about three thousand million years, it remained almost untouched and under the same primitive paradigm. However, in the last five hundred million years or so, it began changing rapidly, accelerating the pace of evolution. The difference between the Ediacaran and Cambrian periods is that in the later one and for reasons that are yet unknown, an explosion of different life forms took place. One of the main divisions that occurred then was that among vertebrates and invertebrates, which still exist today. Among vertebrates we can count ourselves, our dogs, lizards and frogs, and - so it seems - we all have a common ancestor. In 1978, at Crook County, Wyoming, in the United States, some fragmented fossils were found; these, studied in detail, showed some sort of scales on their surface. These fossils were dated as belonging to the Cambrian, about 515 million years ago. Form these fossils it was not possible to deduce the original form of the animal, which was assumed to be a fish without jaws, which is one of their earliest evolutionary stages. This fish was named 'Anatolepis' but little else could be established, except the fact that the fossils found were cast in apatite, which is a mineral that appears as a direct result of the fossilisation process of bones and cartilaginous tissues. So whatever its shape was, 'Anatolepis' is the common ancestor of all vertebrates that came, are now with us, and will be in the same place in the future. |
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