-
46,000 BCE
Precambrian Time
Contains the Hadean, Archean, and Proterozoic periods. Covers approximately 90% of our Earthen history. -
46,000 BCE
Hadean
4.6 billion years ago, the Hadean is what the Earth looked like in the beginning. It was a hellish wasteland of death and destruction, with no life and no basis for it to exist. It continued on like this for around 600 million years. During this time, a planet called Theia collided with the Earth, and the resulting debris orbited the Earth, forming the moon as we know it. -
40,000 BCE
Archean Period
4 to 2.5 billion years ago. This period is divided into four eras; the Eoarchean (4 to 3.6 billion years ago), Paleoarchean (3.6 to 3.2 billion years ago), Mesoarchean (3.2 to 2.8 billion years ago), and the Neoarchean (2.8 to 2.5 billion years ago). The atmopshere was quite different back then, and would actually be toxic compared to what we breathe today. During the Paleoarchean era, about 3.5 billion years ago, the first life appeared on Earth - Prokaryotes, which are a kind of bacteria. -
25,000 BCE
Proterozoic Period
2.5 billion to 542 million years ago. The Proterozoic period is divided into three eras; the Paleoproterozoic (2.5 to 1.6 billion years ago), Mesoproterozoic (1.6 to 1 billion years ago), and the Neoproterozoic (1 billion to 542 million years ago). During the Paleoproterozoic Era, oxygen began to build up in the atmosphere, reaching levels of about 2%. Some time after that, evidence of Eukaryotes began to appear. At the end of the Neoproterozoic Era, evidence of jellyfish also appeared. -
5420 BCE
Cambrian Period
542 to 488.3 million years ago. The Cambrian period is comprised of the Terreneuvian (542 to 521 million years ago), Series 2 (521 to 510 million years ago), Series 3 (510 to 499 million years ago), and Furongian (499 to 488.3 million years ago) Eras. Many phylum made their first appearances in the Cambrian. Dominant Cambrian invertebrates such as trilobites were also present during this period. World temperatures were quite mild at this point in time. -
5400 BCE
Paleozoic Era
Not to be confused with the Proterozoic Period. Contains the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian Eons. -
4883 BCE
Ordovician Period
488.3 to 443.7 million years ago. This period is divided into three parts; Lower (488.3 to 471.8 million years ago), Middle (471.8 to 460.9 million years ago), and Upper (460.9 to 443.7 million years ago). During this period, the area north of the tropics was almost entirely ocean. This period is also best known for its diverse marine invertebrates, including graptolites, trilobites, brachiopods, and early vertebrates. The shallow seas covering Gondwana became breeding grounds for trilobites. -
4437 BCE
Silurian Period
443.7 to 416.0 million years ago. This period is divided into four eras; Llandovery (443.7 to 428.2 million years ago), Wenlock (428.2 to 422.9 million years ago), Ludlow (422.9 to 418.7 million years ago), and Pridoli (418.7 to 416.0 million years ago). Jawed fish and coral reefs made their first appearance during this era, as well as relatives of spiders and centipedes. The first mammals also made their appearance around this time. -
4160 BCE
Devonian Period
416 to 359.2 million years ago. This period is divided into three eras; Lower (416.0 to 397.5 million years ago), Middle (397.5 to 385.3 million years ago), and Upper (385.3 to 359.2 million years ago). By the end of the Devonian Eon, ferns, horsetails and seed plants had appeared, producing the first trees and the first forests. Also during this time, the first amphibians and sharks appeared. -
3592 BCE
Carboniferous Period
359.2 to 299 million years ago.This period is divided into six different eras. Mississippian (359.2 to 318.1 million years ago). Lower (359.2 to 345.3 million years ago), Middle (345.3 to 328.3 million years ago), and Upper (328.3 to 318.1 million years ago). Then there's Pennsylvanian (318.1 to 299 million years ago), Lower (318.1 to 311.7 million years ago), Middle (311.7 to 307.2 million years ago), and Upper (307.2 to 299 million years ago). The first winged insects appeared in this period. -
3592 BCE
Carboniferous Period (Continued)
The Carboniferous Period had ideal conditions for the formation of coal. The ancestors of birds, mammals, and reptiles gained the ability to lay their eggs on land without fear of them drying out. The climate in this period was more humid and tropical, as well as quite uniform. Any seasons that may have existed were indistinct, and difficult to distinguish from one another. Sometimes, warm marine waters would flood the continents. -
2990 BCE
Permian Period
299 to 251 million years ago. This period is divided into three eras - Cisuralian (299 to 270.6 million years ago), Guadalupian (270.6 to 260.4 million years ago), and Lopingian (260.4 to 251 million years ago). At the end of the Permian was the largest mass extinction recorded in the history of life on Earth. It affected many groups of organisms in many different environments, but it affected marine communities the most, causing the extinction of most of the existing marine invertebrates. -
2510 BCE
Mesozoic Era
More commonly known as the Age of the Dinosaurs. We are about to dive in to where velociraptors and t-rexes ruled the planet! This Era contains the Triassic, Jurassic, and Cretaceous periods. -
2510 BCE
Triassic Period
251 to 199.6 million years ago. This period has three eras; Lower (251.0 to 245.9 million years ago), Middle (245.9 to 228.7 million years ago), and Upper (228.7 to 199.6 million years ago). This time was a time of change; the continent of Pangea existed, altering the global climate. It was also during this time that the first dinosaurs appeared, and went on to dominate the Mesozoic Era. The first mammals and earthworms also debuted along with the dinos, although not at the same time. -
1996 BCE
Jurassic Period
199.6 to 145.5 million years ago. There are three eras to this period; Lower (199.6 to 175.6 million years ago), Middle (175.6 to 161.2 million years ago), and Upper (161.2 to 145.5 million years ago). This was a time when giant plant-eating dinos roamed the earth, and small, vicious carnivores stalked those herbivores. Pterodactyls ruled the skies, while long-necked plesiosaurs and wide-eyed ichthyosaurs dominated the seas. Named for the Jura Mountains in which many of these fossils were found. -
1455 BCE
Cretaceous Period
145.5 to 65.5 million years ago. This era is only divided in two; Lower (145.5 to 99.6 million years ago) and Upper (99.6 to 65.5 million years ago). The first flowering plants were found in this period. New dinosaurs also appeared, such as the first cerostopians. We also find fossils of many modern mammals, insects, and birds. This period is mostly known for being the last period of the dinosaurs before the mass extinction that killed nearly all of them, although other species remained intact. -
655 BCE
Cenozoic Era
Wow! We're getting quite close to the present. This Era contains the Paleogene, Neogene, and Quaternary Periods, and is still actually going on. -
655 BCE
Paleogene Period
65.5 to 23.03 million years ago. Contains the Paleocene (65.5 to 55.8 million years ago), Eocene (55.8 to 33.9 million years ago), and Oligocene (33.9 to 23.03 million years ago.) It was during this time that the first horse (Eohippus) appeared, as well as the first apes. The Eocene was thought to have had the highest temperatures of the entire Cenozoic Era. -
230 BCE
Neogene Period
23.03 to 2.588 million years ago. This period is split in two; the Pliocene (5.332 to 2.588 million years ago) and the Miocene (23.03 to 5.332 million years ago.) This period is notable for the appearance of grasses approximately 22 million years ago. The Miocene portion of the Neogene was somewhat warmer than the Pliocene, which had cooled down after the Miocene epoch. Much cooler, in fact, leading to the ice ages of the incoming Pleistocene. Yet, the Pliocene was still warmer than it is today. -
25 BCE
Quaternary Period
2.588 million years ago to... well, today! This period only splits in two; Pleistocene (2.588 million years ago to 11,700 years ago), and Holocene (11,700 years ago to present). It was during this time that the first Homo Sapiens, also known as human beings, came into being. Near the end of the Pleistocene, humans had spread throughout most of the known world. And, more recently, here comes the Holocene, which, if you want to know what life was like there, just look around! -
The Present
Welp! We're done. Thanks for going on our travel through time, and I hope we've learned something from this. Now, feel free to roam freely about the present, and be glad there aren't any dinos around anymore!
