What is the oldest known fossil?

The oldest known fossil is Stromatolite (which means a "mattress rock" in Greek) dating 2.74 billion years ago. Stromatolite is a laminated acretion structure created when bacteria, especially photosynthetic cyanobacteria, sediment trap between biofilms they create.

Trees come in different shapes and sizes, including cones, columns and branch types. For a long time, stromatolites have not currently been (too many pastures) until they were discovered in isolated high -end salt ecosystems such as Shark Bay and Lake Thetis in Australia and Cuatro Cienegas in Mexico. Like the horseshoes, the stromatolites are considered "living fossils" due to their age. There are even older formations similar to the Standard, even Further back than 2.74 billion years, as well as candidates for the oldest known fossil, but no one is confirmed by the scientific community. These photosynthetic bacteria converted carbon dioxide into a large scale, changedThe composition of the atmosphere and caused the so -called "oxygen disaster", which at that time would kill many other organisms for which the oxygen was resistant.

There are non -nebiological structures similar to stromatolity, which can be confused for the oldest known fossil, but means nothing but clotting small crystals. They were not observed today, but it is assumed that the conditions in the oceans of the past could be mature for their creation.

The oldest known fossilies of animals will not appear until the Middle Ediacaran period, about 600 million years ago. These include a number of simple mushrooms, cnidarians (like modern hydrate) and even simple bilateralians (organisms with bilateral symmetry) that resemble small balloons. These animals appeared shortly after the greatest ice age in the history of the planet, which caused the glaciers on the equator to form on the surface of the sea.