There were no life forms as we know them during the Proterozoic period. With oxygen just then being accumulated in the earth's atmosphere, it brought the first advanced single-celled eukaryotes and multi-cellular life forms.
The answer is Proterozoic.
they were probably the first multicelluar life- forms
The longest in geological time is an Eon eg. Archeozoic Eon . Edit: there is also the supereon, which is usually composed of 2-3 eons.
According to the theories of Charles Darwin complex forms of life evolved over long periods of time from simpler forms.
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The Proterozoic is a geological eon representing the time just before the proliferation of complex life on Earth. Most life forms at the time were single celled organisms.
the eon that constitutes the earlier (or middle) part of the Precambrian, in which there was no life on earth. It precedes the Proterozoic eon. Also called azoic .
Hadean, Archeozoic, Proterozoic, Phanerozoic
The Proterozoic eon was the third eon in Earth history. It lasted from 2.5 billion years ago to 542 million years ago. Therefor, the Proterozoic was nearly 2 billion years long.Read more: How_long_did_the_proterozoic_era_last
The eon that lasted from 2,500 to 542 million years ago was the Proterozoic Eon.
Precambrian is an informal term for the time before the Cambrian Period, the first period of the Phanerozoic Eon. The Precambrian consists of three eons, the Hadean, the Archean, and the Proterozoic. The Hadean Eon is about 760,000,000 years long. The Archean Eon is about 1,300,000,000 years long. The Proterozoic Eon is about 1,960,000,000 years long This comes to a total of 4,025,000,000 years.
The largest divisions of the geologic time scale are: Hadean Eon (4.6 to 3.8 billion years ago) Archaen Eon (3.8 to 2.5 billion years ago; this is when the first bacteria existed) Proterozoic Eon (3.8 billion to 542 million years ago) Phanerozoic Eon (542 million years ago through today; this is when the first complex multicellular life forms evolved.)
During the Archean Eon life started and was dominated by one-celled prokaryotic life forms. Eukaryotic one-celled organisms became dominant in the Proterozoic Eon. Multicellular organisms ruled the planet during the eon known as the Phanerozoic.
The Archean Eon, which is part of the Precambrian period along with the Proterozoic Eon.
An eon is a made up of two or more eras. They are defined in terms of what was happening on the planet in biological and geological terms rather than in number of years. We are now 541 million yeras (Myr) into the current eon - the Phanerozoic eon. Before that was the Proterozoic eon which lasted 1959 Myr, the Archean eon (1500 Myr) and the oldest, the Hadean eon (500 Myr).
The middle Proterozoic comes the first evidence of oxygen build up in the atmosphere. This is how the eukaryotes formed. They include multicellular algae.
Neoproterazoic Era in the Proterozoic Eon (1Ga to 542 Ma)