The earliest period of development and the ancient crust of the earth - is Archean era.It was at this time according to scientists were the first living organisms, heterotrophs that as the food used various organic compounds.At the end of the Archean era were formed the core of our planet, intense volcanic activity decreased, because of which the world has started to develop life.
Archean era began about 4 billion years ago and lasted for about 1.56 billion years.Divided into four periods: neoarchean, paleoarchean, mesoarchean and Eoarchean.
crust in the Archean era
During neoarchean, which took place around 4000-million years ago, Earth had been formed as a planet.Almost the entire area was occupied by volcanoes that have erupted in a lot of lava.Her hot formed continents rivers, plateaus, mountains, and oceanic trenches.Permanent activity of the volcanoes and high temperatures led to the formation of minerals - ore, copper, aluminum, gold, building stone, radioactive metals, iron and cobalt.About 3.67 billion. Years ago formed the first metamorphic and igneous rocks (granite, diorite and anorthosite), which were found in different places: the Baltic and Canadian shields, Greenland and others.
During Paleoarheya (3, 7-3,34 billion years ago) the formation of the first continent - Valbaru and single ocean.The structure ocean ridges changed, leading to a gradual increase in the amount of water and reduce the amount of carbon dioxide in the atmosphere.
mesoarchean Then followed, during which the supercontinent slowly began to crack.In neoarchean ended about 2.65 mldr years ago, formed the main land mass.This fact speaks of the ancient continents of our planet.
climatic conditions and the atmosphere
Archean era was characterized by a small amount of water.Instead of a single vast ocean were just shallow pools located separately from each other.The atmosphere consisted mainly of gas (carbon dioxide - CO2 chemical formula), its density was much higher current.The water temperature was 90 degrees.Nitrogen in the atmosphere was a little, about ten to fifteen percent.Methane, oxygen and other gases was practically no.The temperature of the atmosphere, according to scientists, reaches 120 degrees.
Archean era of biology
During this era is the emergence of the first protozoa.Anaerobic bacteria are the first inhabitants of the Earth.The Archean era came the first photosynthetic organisms - cyanobacteria (pre-nuclear) and blue-green algae, which have started to allocate to the atmosphere from Earth's oceans free oxygen.This has contributed to the emergence of living organisms that can survive in an oxygen environment.
But Archaeozoic era is important, not only the appearance of photosynthesis.At this time there are two most important evolutionary developments: there are multicellular and sexual process, which dramatically increased the adaptation to environmental conditions because of the establishment of the set of chromosome combinations.
