The Firsts Life on Earth is Acritarch
The name of the acritarchs is first derived from the paleontologist Evitt in 1966 which means “uncertain of origin”. The group is named artificially not found in nature as the same fossils in the rocks recorded under this group. Because acritarchs are still unknown organisms. Much research has been done so far but the exact origin of acritarchs has not been identified.
Based on the evidence, some, scientists claimed them to be similar to the algae, probably the cysts of planktonic eukaryotic algae, the carbon isotope study of the acritarch says the delta 13 carbon value is similar to the planktonic marine algae. (Kliti Grice et al 2005).
The size ranges between 20-80 microns of acritarchs. The acritarchs are mainly unicellular and can be identified using a light microscope. They are characterized by varied sculptures and are spiny and smooth on the surface. some times spikes of the acritarchs cannot be found due to heavy treatment of the laboratory experiments. so, during the laboratory experiment, one must be careful to use very carefully to get the unaltered fossils. the acritarchs are mainly the organic-walled microfossils of the uncertainty of origins.
Size and age ranges of acritarchs:
The oldest known acritarchs are from the shale formation of the Soviet Union of the Paleoproterozoic age. (1900-1600 Ma). They are stratigraphically abundant from Upper Proterozoic to the Permian. From the Devonian onward the abundance declined. The morphological size of the acritarchs are microscopic and ranges from 20- 80 micrometer.
Classification of acritarchs so far had not been done based on their natural appearance. But Downie and Evitt introduced an artificial scheme of classification that is so far widely accepted among paleontologists.
Application of acritarchs:
Acritarchs are extremely valuable for the stratigraphic correlation of rocks of the Proterozoic and Paleozoic ages. they are useful for paleoenvironmental interpretation where there is less fossil evidence than acritarchs.