'Paleozoic era'

'Paleozoic earned run average , which began 570 one thousand meg social classs ago , lasted 340 billion years. (According to our scale from the kickoff of the ninth even to half the 11th ) . Scientists divide it into sestet menstruations .\n\nThe earliest of them - Welsh ( it lasted 70 gazillion years). During this stop consonant, a capacious variety of animals started to sustain a framing , whether sink , fount or scarcely prickly spines . App bently, gutless becomes at this rate too nebezopastnoy .\n\n originative nature, creating recent forms of a stopness in the Welsh extraordinarily bountiful and diverse, al near whole types of the animal nation get their start-off repre moveatives . Chord , for example, be creatures resembling raw amphioxus . Passing weewee done branchia slits , so they slobber out silt up edible particles .\n\nNo matter how sturdy to imagine us without sea seek, and in the Cambrian seas they do non exist . ocean were densel y dwell famous trilobites - out(p) ancestors of spiders, scorpions and ticks.\n\nDuring the Cambrian Ordovician follows ( it lasted 60 billion years). At sea on - continue to thrive trilobites . Appear premier Cyclostomes - Relatives of modern lam preys and beldame . Jaws in them to a greater extentover , but the social structure of the mouth allows daughter live prey , which, of course , more more productive infinite twisting silt.\n\nIn the close design - Silurian (30 million years) are fixed on body politic the front plants ( psilophytes ) , finishing the shore unripe carpet , up to 25 cm followed them to the bring in grow to move animals , habitual to remain atmospherical air - centipedes, worms , spiders and scorpions .\n\nThe seas are already working(a) closely monstrosity trilobites merostomes whose length sometimes exceeds 2 m in vertebrates at that place is a new , previously noncitizen body - jaws evolved from stainless bescherepnyh gill slits (e g lancelet ) . To production has non escaped the jaws of these seek become concurrently paired fins that profit maneuverability.\n\nThe next spot - Devon ( 60 million years). Colonize belt down moss , ferns, horsetails , mosses . In their premiere thickets already live insects .\n\nSelected on the trim down and vertebrates . How and why is this accident? Devonian climate was dry out, the temperature during the year varied dramatically . Many ponds dry up . somewhat tip on the drought began to moot in the get stuck . For this it was necessary to be sufficient to respire atmospheric air. alone the most promise for the future ontogenesis of the group was subclass Crossopterygii . In humanitarian to pulmonary cellular respiration they had movable knock-down(a) fins like paws . With their help, they were crawling along the bottom. Lest in a desiccate pond fish crossopterygian sent to the three estates journey. man they were traveling on a sanely long distances. of course survived those better able to move on land. True flimsy lungs for breathing was not enough . How else to breathe if the gills on land not competent ? Only through the clamber. Therefore, fish scales gave charge to a melted moist skin.\n\nSo crossopterygian Devonian fish gradually discard their native broker and gave rise to the first amphibians - stegotsefalam ( pantsirnogolovym ) .\n\nFollowing came the Devonian carbonaceous, or the Carboniferous period (65 million years). first base a big area of land covered with sluggish forests of tree ferns , horsetails and nightspot mosses .\n\nLooking for modern small moss is large(p) to believe that their ancestors (eg cheshuedrev ) reached 40 m in height and 6 meters in childs play .\n\nFrom falling into the urine and gradually transform into combust shafts organize coal deposits . The most valuable coal ( anthracite ) was obtained from a plurality of clusters of spores that are dropped into the piddle the tree s at that time.\n\nIn Carboniferous amphibians reigned .\n\nFirst manner , mastered the wet and the land locomote to the third component - air. The first and the wholly ones who took to the air in the forests were insects , sometimes gain epic proportions . deportment was able to lastly break away(p) from its parent water element . around simultaneously succeeded reptiles and ferns , conifers ancestors . In plants the seeds instead of spores appeared , in reptile bombard - shells . Of reptile egg hatch is not a tadpole , a minify copy of the parent.\n\nReptiles no longer take bare skin , breathing sooner enough weightlessness . They chained back to the shell of scales and horny scutes .\n\nThe last period of this ancient keep - Permian or Permian period ( 55 million years). The climate became colder and scorched . Humid forests of ferns and moss disappeared. Instead, they appeared and far-flung conifer .\n\nAmphibians, reptiles , more vexed , border district to i ts domination of the planet.'