The age of the Earth is estimated at 4600000000 years. During this time of immense, the Earth has grown from a cloud of cosmic dust that constantly change into what we know today.
The first time the Precambrian period covered by the first beginnings of the Earth appeared at the time of the first stone. These rocks contain fossils that have been possible, at the age of a rock layer to be determined. Non-fossilRemnants of Precambrian you wanted. It is not possible to give precise information about the origin of rocks from this time, because through this time, the Earth has been evolving. And 'possible to classify only certain processes of mountain formation (especially in North America, Greenland and Scotland - Laurentian plateau training).
The earth probably arose as a result of cluster formationtiny particles of cosmic dust and gas, they were constantly bombarded by particles of mass and new arrivals, until the whole mass began to revolve around the sun as the third of nine planets. In the beginning the earth was hot and covered with numerous volcanoes. There was no oxygen and the atmosphere. At this stage, life on earth was impossible.
The earth has cooled slowly, so that escape of water vapor and gases, and create an atmosphere. He beganrain and the oceans formed. It 'probably the first single-cell animals already 3600000000 years, has grown old, probably from a combination of molecules spontaneously. Later developed algae and bacteria, and then divided the first multicellular animals, and as cnidarians (coelenterates), ranging from simple cavities, which are made from soft tissues.
4000000000 Some years ago the earth had a solid crust. Later, about 3900000000 years, water has begun toFormed on its surface. Huge masses of land are a few years 3000000000. In the past, they had changed their shape and distribution. Of a single huge continent covers the entire surface of the earth, the first two continents, who drove from one another and said further developed.
The Precambrian is followed by the Paleozoic. Our knowledge of this period is based mainly on the development of animal life (fauna). The fossils were found in rocksto appreciate the layers of the earth and with the determination of their age, it was possible, the age of the individual layers. The most important fossils of this kind are the trilobites and graptolites. Yet, in this immense span of time, there have been numerous molluscs, crustaceans, the first vertebrates, etc., which grew more and more diversified. By the end of the Paleozoic Era, there were the first vertebrates - reptiles, shed their eggs on the ground. They have evolved fromAmphibians. In addition, during the Paleozoic era, has created the Ural Mountains, the unification of Europe and Asia in a continental block. The Appalachian Mountains at the end of this era is.
During the following period emerged in the Mesozoic era 66 million years before the completion of the South American Andes and the Rockies. A mass extinction occurred about 90 percent of all animal species. For a long time dinosaurs dominated life on Earth. These included residents ofThe oceans, land animals and flying dinosaurs. However, they were not the only ones that have been developed. Early birds and even small mammals began to appear. During the Jurassic period, then the central part of the Mesozoic, an important part of the landmass of Europe has been flooded, but when the consequences of the Cretaceous period, this continent has returned to its original shape. These floods one explain the fact that marine fossils have been found in mountainous areas. When the dinosaurs andmany reptiles have died, and the beginning of the Tertiary era of the last 65 million years of Earth, Cenozoic era began, a large variety of mammals appear. 55000000 A few years before the horses, animals and ungulates trunk (cloven-hoofed ungulates, or hoofed animals), appeared first, followed by (38 million years) in anthropoids (monkeys), pigs, deer and other animals. The mountains of the Alps, Pyrenees, Caucasus and Atlas emerged in this period.
DuringQuaternary Period of the Cenozoic era (after the Tertiary) was the global climate change. Cold spells with interglacial periods, huge glaciers and vast ice sheets formed and changed inside in the warm periods that followed, it spread flooding as a result of the merger of these ice masses. Modern man has emerged at the end of this period.
The earliest date for the period of the Earth (Precambrian)
Geologically, Precambrian period of the first period.It covers the period between the formation of the earth's crust more than 4000000000 years before the Cambrian, about 590 million years ago, and represents more than 80 percent of the entire history of the earth.
The oldest part of the Precambrian, as archaic, 1500000000, the first year provides for the creation of the earth. We know very little about this period. Nor is it entirely clear how the Earth was formed. Some of the sun canhave broken, what in the planetary system, which is our land, or it may be the result of the grouping of cosmic particles were.
The prevailing hypothesis is that if the sun by the enormous heat and cooling (contraction) have emerged, began to cool. Particles of matter swirling around the sun have been converted to gas condensate substances, radioactive and ice, the formation of new celestial bodies (asteroids). The asteroid, because of their gravity, pulling more and moreParticles to become planets around the sun.
It took years to develop at least 10000000000 sun and protoplanets. The process of formation of the planets with their moons, perhaps about 5000000000 years completed. We call this period "the Star-era." This is when you start the Archaic period. After its creation, the earth began to cool. This process went relatively quickly, because the temperature difference between the universe and the Earth's crustwas considerable.
The atmosphere was probably mostly water vapor, carbon dioxide, methane and nitrogen, and cooled. He began to form water evaporates constantly, until in "Ur-rain" turned and flooded the earth's surface, cooling it further. The stones were scattered along the existing layers of rock and formed first. Oxygen is essential for animals and plants that did not exist, why could not life originate on Earththis time.
The Archaic period is determined by the Proterozoic period. In recent years, the rocks in various regions of the world, which were discovered after detailed investigations and calculations derived 3800000000 years. The first date of sedimentary rocks from South Africa and Greenland. There are very few fossils of this period and most of them are petrified trees. In the first rocks are very ductile filament and micro-organisms - single-celled algae,while in younger rocks, there is already branching primitive filamentous algae and fungi (lichens). These were found in coarse-grained limestone in Ontario and in the rocks of Minnesota and the United Kingdom.
The fossils of Precambrian animals have been very rarely reported. Probably only at the end of this period were articulated mainly cnidarians, hydroids and jellyfish. For those of fossil mollusks was quite difficult and the results are very rare. During the CambrianTime, however, began living organisms with parts of the solid body on a large scale, so their fossils are more frequently occur. Apparently during the Precambrian, continental regions barren and empty.
There were probably inhospitable masses of bare rock, and the slow emergence of life forms develop in shallow seas. During the first prokaryotes (ie no core) "primordial soup" and consumed during the process of acquiring energyexempt only a small amount of oxygen in the presence of organic matter interaction with solar radiation, oxygen production increased significantly.
It was in this way increases the amount of oxygen in the atmosphere that draws the conclusion that the formation of a protective ozone layer, harmful UV rays, which could only under this protective layer of life on Earth.
It is assumed that the temperature between 0 and 50 degrees Celsius, it was becauseonly on the basis of this hypothesis, life could have originated. It 'possible that at this time covered, the ice cover large areas. It can be assumed, however, that the earth is completely covered by ice. As documented by numerous fossils, developed a series of primitive marine animals in the Cambrian soon.
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PaleozoicEarth
The Paleozoic of the earth is the time between the Precambrian and Mesozoic periods. This lasted about 340 million years and is divided into several stages: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian.
Cambrian is the first part of the Paleozoic Era. Its name from the Roman name for North Wales will be taken, "Cambria", where the rocks found from this period. At that time about 590 million years ago, the continentsformed a giant supercontinent 'Gondwana'. And 'covered the continents of Africa, Antarctica, South America, Western Australia, and parts of India, Florida, Mexico, southern Europe and perhaps China. These continental masses were in the southern hemisphere and extended almost to the South Pole. They came from the north by a broad band separated from the sea and then followed the North Pole to the other land masses separated by more complexSeas.
First, the climate was cool to moderate. Place later on global warming, as documented by scientific studies of red sandstone and salt deposits, such as salt and gypsum.
A complete development of flora and fauna during the Cambrian period begins. In the seas developed a diverse set of animals, such as fungi (molds), trilobites, crustaceans and similar creatures, who had a hard exoskeleton. There were prehistoric shellfish. Everyone lived on the seabedand there were jellyfish in the waters. Flora consisted mainly of a variety of algae and seaweed. Terrestrial plants and animals were still alive, but later developed.
The Cambrian period is followed by the Ordovician. This period has inhabited its name from a Celtic tribe of North Wales Ordovics and covers the period 505-439000000 years. The location was similar to that which existed during the Cambrian, but the continentscontinue to converge and their coasts were flooded more and more. There was an ice age during the Ordovician. In South America you can see the moraines deposited by glaciers. The fauna of invertebrates in the oceans derive mainly in hot climates.
Deposits show a dark slate who lived in the deep waters of the multi-cell (metazoans) graptolites, an extinct species of flagelliform formed with a hard outer skeleton of chitin, the colonies. A wide range ofdeveloped tendonitis in shallow seas. Grained limestone in layers, usually found brachiopods and bryozoans, relatives of today's mussels, as well as a wide range of trilobites. The body of this was articulated by an exoskeleton, covered, consisting of three interconnected parts. In addition, there are corals and sea lilies. The first vertebrates emerged, and possibly the first primitive fish fins, but it is not over yet, or jaw.
There were no complex machines yet, but blueand green algae have spread from sea water salty, cool coastal waters. Traces of traces of animals such as reptiles, centipedes have been found in fossil beds from the Ordovician. If any species were in the country would be planted to have to get these animals. But after extensive research and calculations, the plants have until the following period, the current so-called Silurian.
The Silurian period, the third period of the earthPaleozoic stage and its name is derived from the pre-Celtic tribe Silurs, who lived in Wales. It encompasses a period between 438 and 408 million years ago.
From a geographical point of view, there existed two completely interlocked continents; the northern part called the Laurasia and the southern part called the Gondwana. Both parts were alternatively more or less under water. The north pole at that time was probably in the northern Pacific Ocean and it is assumed that the south pole was situated in southwestern Africa. The equator crossed from southeastern Europe, over northern Australia and Greenland to the centre of America.
The climate was mostly humid and warm, turning a little drier at the end of the Silurian. This is indicated by limestone, gypsum, and rock salt dating from that time. This rock salt forms today's salt deposits.
The most common marine animals were invertebrates such as graptolites, trilobites (articulates), and simple corals (cnidarians). Crinoids, as common at that time as algae, consisted of calycinal bodies anchored in the bottom of the sea by means of their stalk. Their bodies were surrounded by tentacles. Corals, which built enormous cliffs that still fascinate scientists today, became extinct approximately 230 million years ago. They were replaced by today's corals, now found in warm seawaters. Marine scorpions and articulates grew to gigantic proportions of up to two metres (Pterygotus).
First jawless fish, which did not have bones but rather a cartilaginoid skeleton, appeared in the seas. We are aware of their existence because they had small bony plates on their head and body, where these plates became fossilised. Two of these species survive today: the eel-like fresh-water lampreys and the slimy, worm-like blennies (blenniidae). At the end of the Silurian period, the first primeval ferns and club moss (lycopodium) appeared on land.
The Devonian period, the fourth period of the earth's Paleozoic stage, which is named after the English county of Devonshire, comprises the period between 490 and 360 million years ago.
The land masses of the continents were constantly moving also during this period. The climate of the northern hemisphere was warm while, in the area of the south pole, there were several ice belts. In linkage to the first beginning in the preceding Silurian period, the intensive evolution of higher types of terran plants continued. These plants were generally horsetails and ferns which, in the late Devonian period, would grow as tall as trees. Thus fauna was injected with new evolutionary impulses.
Numerous new kinds of animals began to evolve, mainly fish. The Devonian period is therefore also called the period of fish. The jawless fish of the preceding Silurian period evolved into shield-headed fish which, as the first vertebrates, also had jaws. Originally the skeleton of the first vertebrates was not formed by bones but by cartilaginoid matter.
During the Devonian period, there were also thorny-finned/lobe-finned fish (ichthyostega). They had thick fins and rigid skeleton and they were able to remain on land. By means of these fins, they could move on land and even abandon a dried-out lake or river and find another water habitat. The ichthyostega are considered as a transitional form toward land animals.
The sea was the habitat mainly of corals, ammonites, snails, conchoidal crayfish and echiderms, as well as trilobites and similar kinds. Scorpions, arachnids, terran reptiles, myriapeds and early, wingless insects were evolving on land.
The Carboniferous period (from the Latin word for coal), is the fifth geological segment of the Earth's Paleozoic. This period, which began 360 million years ago and which ended 286 million years ago, is also called the period of anthracite because, during that time, the largest deposits of this coal in the history of the Earth were formed, a result of a conjunction of favourable climatic, biological, and geological factors.
The climate in central Europe, which at that time was situated near the equator, was tropical and humid, similar to the climate that is found today in the rainforest of the Amazon. During the course of the Carboniferous period, there were powerful movements of the lithospheric plates which resulted in the formation of mountain ranges and valleys between them. Many regions were alternately just above the sea level and slightly below the sea level and dense forests grew in the coastal regions. These were periodically covered by water; when the sea level decreased, these forests underwent vigorous growth again.
The forests consisted of club moss growing up to 30 metres, ferns and horsetails and resembled today's tropical swampy forests. As a consequence of the fluctuation of the water levels, these forests were constantly flooded by water, which formed sediments. When oxygen could not penetrate, peat began to form and later on coal.
The first land vertebrates began to evolve in this environment. The transitional form between fish and land vertebrates (ichthyostega), numerous kinds of amphibians (amphibia), as well as amphibians with rigid skeleton began to evolve.
At the end of the Carboniferous period, many animals using only lungs for breathing and which were are not forced to live only in water, begin to appear. These reptiles did not have to return to the water to lay their eggs in that their eggs generally had leathery shells providing protection against predators and the weather. The group (anapsida), predecessor of today's turtles, was among these reptiles.
During the Carboniferous period, there also lived gigantic myriapods reaching lengths of up to one metre, arachnids, scorpions, prehistoric dragonflies (meganeura), cockroaches, and insects. They lived in higher situated forests consisting already of conifers. Analogous to the Devonian, numerous kinds of algae, plant and animal single-cell organisms, corals, ammonites, and articulates inhabited the oceans. By now, the trilobites had disappeared, although a great variety of fish continued to exist.
The southern hemisphere of the globe was completely different. There was still Gondwana, the continuous continent consisting of a part of North America, India, Africa, Australia, and Antarctica. A major portion of this continental mass was situated near the equator of that time and, during the transitional period toward the Permian period, was covered by gigantic ice mass (the Permian-Carboniferous ice age). When, at the end of the Carboniferous period, Gondwana moved over the south pole toward the north, it collided with Laurasia to form a contiguous continental mass called Pangea.
The last geological period of the earth's Paleozoic stage was the Permian period. It represents the period between 286 and 248 million years ago and was named after a former Russian province of Perm situated west of the Ural Mountains.
At that time, Gondwana connected with the northern continents to create a gigantic continental mass called Pangea, resulting in an extensive rising of mountains. This supercontinent was surrounded by a great ocean (Panthalassa). Here, corals, ammonites, and large single-cell animals continued to exist. This was the only period when all the continents formed one continental mass.
Many of the kinds of animals indicated earlier became extinct during the Permian. Causes of this phenomenon are not clear. It is possible that it was linked to the gradual receding of the oceans.
A number of the amphibian animals remained in the vicinity of the water. Another part of this group gradually withdrew. During the Permian period the amphibians of the earth's Paleozoic stage reached their greatest expansion, although this period brought changes for the amphibians. In some regions simultaneously appear early forms of reptiles similar to mammals. They were forcing the amphibians out of their environment or at least competed against them for the space.
Following the unification of Laurasia and Gondwana, the prehistoric amphibians and reptiles penetrated into Gondwana, where these kinds of animals did not exist yet. During the Permian period, there begin to appear cammsaurs - real reptiles. Dimetrodon a Edaphosaurus are examples of this group.
The flora of this period is characterised by the penetration of conifers and the appearance of ginkgophyta. Club moss, horsetails, and ferns, which depended on humid and warm climate, began to recede.
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