What are some milestones in evolution?

Life development begins very long ago: in the past approximately 4,000 million years. Life began shortly after the bark of Earth had cooled and was created by well -defined continents and oceans when the planet was only about 600 million years old. This ancient period is called Hadean Eon as unpleasant circumstances that prevailed on the planet at that time. Despite the heavy bombing of meteor and surface temperatures much higher than today's primitive self-production RNA and DNA chains have emerged and eventually evolved into proto-cells that are ancestors of all earthly life.

There are many things that we do not know about abiogenesis, scientific name for the origin of life and the starting point of evolution. Perhaps it was deep underground or in hot places in the ocean with the right chemical reactions. Because the atmosphere at that time was completely missing oxygen, the first simple cells used carbon dioxide as Cazdroj rbon and oxidized inorganic materials for energy extraction. In any case this earliest lifeHe didn't leave any fossils, so we don't know much about it.

Some of the first known forms of life were prokaryotic (without core) cells that may have begun to leave the basic microfosily about 3.5 billion years ago. These cells used glycolysis essentially conversion of sugars to ATP as the basis of their livelihood. About 3 billion years ago, the most important milestone of evolution before our species was created. It was the arrival of photosynthesis, a pioneer of cyanobacteria, which now cover the Earth's surface in huge numbers. The use of water as a reduction agent produced oxygen as a by -product, which caused the atmospheric oxygen level to rise and continue to rise. This milestone in evolution was called an oxygen disaster because it massacre most of the organisms around the world that could not survive in an oxygenated environment. We can find out when it happened because layers of the period begin to contain iron oxideor rust.

2,100 million years ago, more advanced cells called eukaryotes with cores and specialized organelles have evolved. People are large balls of eukaryotic cells. It took another billion years to create complex multicellular colonies of evolution, followed by descendants of all animals, choanoflagellates, only 600 million years ago. These were the first multicellular organisms with specialized components that allowed them to navigate after eating and develop raw sensors. Evolution has created our precursors.

Evolutionary progress, which led to all the basic physical plan and complex organisms in general, was a Cambrian explosion, a jump in evolution that occurred about 542-530 million years ago. This set the ground for everything else. It was only a matter of time before the life of colonization on Earth began, developing complex nervous systems and eventually intelligence.