The Time Traveler's Guide

to the Earth

A walkthrough for the longest sandbox game in existence

preCambrian - Cambrian - Ordovician - Silurian - Devonian - Carboniferous - Permian - Triassic - Jurassic - Cretaceous - Paleogene - Neogene

Image Credits

The

Hadean

Range: 4.6 bya - 4 bya (~600my)

Think about the name for a moment - Hades. This is the hellish beginning of the planet. A violent time where earth was forming and settling its metallic core and its crust. The world's longest tummy ache???

The Hadean and the next two eras are what make up the 'PreCambrian'; which is actually 7/8 of the earth's timeline.

There are no significant geological remnants left of the Hadean as the earth has recycled most of itself by now. But the traces we have match the oldest rocks we have recorded in our solar system, so there is some agreement on the Hadean's age and general starting point.

Pictured: Volcanic lava. Image Credits

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Life?

Possible! But vulnerable to frequent extinction events, as there is a lot of asteroid and volcanic activity. There is not very much stone left to look at. Most of the Hadean has since gotten swallowed up and reformed into the crust due to natural activity.

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Survivability check-in:

No. I mean most the water is vaporized. The land is pretty volatile and full of volcanic areas. Your biggest threat is probably the temperature though, at 200 F - 446 F, or the atmospheric pressure being near the human-tolerable limit, and also, there is 0 oxygen, but I think the heat would probably cook you out of your mind before you could properly asphyxiate?

This is also the point in time in which the planet is theorized to have collided with Theia and to break apart, forming Earth and the Moon. Credits

The Earth may have appeared orange due to a methane atmosphere. Credits

This is not an earth you would recognize. There is no oxygen, most the water is vaporized, the crust is quite active with volcanic activity. It is very, very hot.

The

Archean

Range: 4 bya - 2.5 bya (~1,500my)

Water World! There is now an earth's crust, but most of it is under the ocean. The crust is still significantly hotter than it is today. This is the era of 'settling down'.

The remaining bits of the Archean can be found only a few areas in the world. Wyoming, Minnesota, Scotland, India, Brazil, western Australia, southern Africa. Archean rock makes up about 8% of Earth's crust today; the rest has been recycled.

It is sometimes referred to as the 'boring billion'.

Pictured: Ocean. Image Credits

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Life?

Yes! We have microbial mats and evidence of certain types of bacteria. So far, it is only single-celled prokaryotic life. These microbes also appear to have colonized land.

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Survivability check-in:

No. There's nothing to eat. Now water covers much of the earth. The air is unbreathable, there is no free oxygen! In short: you are dead in minutes! Likely due to asphyxiation. You'll get to see a pretty endless ocean, though.

Purple Earth Hypothesis. It is proposed that early photosynthetic life was retinal-based and therefore the microbial mats gave the earth a purplish color. Credits

There is a lack of extensive geological evidence for specific continents. However, trace evidence causes some scientists to dub a supercontinent called 'Ur' and others to claim one called 'Vaalbara'.

Despite a variety of factors, such as the sun being dimmer than it is today but also the presence of more greenhouse gases, the earth's temperature is about modern levels.

The

Proterozoic

Range: 2.5 bya - 538.8 mya (~2by)

The Great Oxidation Event! The Oxygen Catastrophe! The Oxygen Crisis! Oxygen Revolution? Oxygen Holocaust? Suddenly, there is a lot of free oxygen, this is theorized as the biproduct of photosynthesizing bacteria, such as cyanobacteria. Up until this point, most life was anaerobic, causing a mass die-out and rebuilding of earth's life.

This period is also noted as having two enormous glaciation periods, which scientists argue the exact reason and nature of ( see Snowball Earth ). By the end, volcanic activity as well as perhaps the oxygenation of the oceans brought the earth out of the self-perpetuating cold snap.

The last ~30 million years contains the Avalon Explosion. This is thus named due to an unexpected presence of animal life fossils found before the Cambrian period ( "animal life" being the defining marker of Cambrian, oopsie ). It was a fast and diverse boom of small eukaryotic animal fauna with bilateral or otherwise symmetry, with some being identified as belonging to families of worms, sea arthropods, starfish, and jellyfish, and the extinct Vindobionta group, a plant-like sea frond animal.

Pictured: Snowy mountain range and ocean.Image Credits

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Life?

Yes indeedy! We have small eukaryotic animals out the ass towards the end. Mitochondria and chloroplasts are already BFFs. There are photosynthetic bacterias as per usual and the first fungi. Also sponges! Our sturdy snowball earth survivor.

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Survivability check-in:

No. The oxygen level even after the Oxygen Crisis is around 1/4th of modern times, so you will die quite shortly. Beyond that, there is nearly nothing human-edible to eat, and it is all extremely small and in the ocean. Towards the last 30~ million years the Avalon Explosion occurred, where there are the beginnings of the jellyfish and sea star members, some early molluscs. But I don't think you will be surviving on those.

"Snowball Earth". Or perhaps Slushball Earth?

Dominant Continent: Columbia, which broke up and reformed as Rodinia, which then, you guessed it, broke up and reformed as Gondwana. ( We have not even gotten to Pangea yet. )

There are numerous extinction events attributed to ice ages and anoxic oxygen level events.

CONGRATULATIONS! 🎉

You made it through 7/8ths of Earth's timeline! That is THIS MUCH!:

Didn't take too long, did it? Okay, okay, here we go with the actual animal lifes now...

Tree of Life so far:

I left out a ton of lil worms and amoebas for brevity.

Pictured: coral. Credits

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Survivability check-in:

No. Not enough oxygen yet, it is impossibly low top-side. You will die quickly.

The

Cambrian

Range: 538.8 mya - 386.85 (~51.95 my)

The Cambrian was originally defined as the "start of animal life" and this was before precambrian fossils were found a la the "Avalon Explosion". But the dates had already been set, whoopsies!

Event: The Cambrian Explosion. This was when multicellular life REALLY took off. Also, we may have an effective ozone layer now? Which may have helped with the survival of life??? Who knows. The Cambrian consists of a variety of named stages marked by first appearances of certain categories of life and extinction events. It's quite detailed but I will not get deeply into them.

Pictured: Ordovician shoreline.Credits

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Survivability check-in:

No. The atmospheric oxygen is now up to 13-15%, but that's still too low, as the bare-minimum for humans is 19.5%. Below that, you experience impaired cognitive abilities and adverse physical affects. You will feel sick and die, unable to problem solve your way out of anything if you wanted to. And that is if you warped in during the summery parts of the Ordovician - there are extreme glacial events too.

The

Ordovician

Range: 486.85 mya - 443.1 mya (41.6 my)

This period is marked by futher mollusc and arthropod domination. Some arthropods such as the arachnid family move onto land, so does the plant family, likely evolving from green algae into non-vascular simple plants like liverworts.

Event: Halfway through we have the Ordovician Meteor Event - a mostly harmless event marked by frequent meteor showers.

This time also saw the construction of the Appalachian Mountains through tectonic activity. The Laurentia and Gondwana continents were separated. Overall there was a lot of tectonic and volcanic activity.

Extinction Event at the end: This mostly affected conodonts and planktonic forms, and wiped out many trilobytes. Other familes were also heavily affected. This was possibly due to another large ice age.

The

Silurian

Range: 443.1 mya - 419 mya (23.5 my)

This period is springing out of the previous extinction events where 60% of marine genera were wiped out. A "recovery" period. 3 groups of arthropods colonized land! Myriapods (millipedes/centipedes), arachnids(spiders, sea scorpions, harvestmen, etc), hexapods(contains all insects).

There are also the first vascular plants!!! Our humble Cooksonia, while small, is the start of a plant revolution that will help them soar to new heights. Meanwhile, however, one of the biggest kids on the terrestrial block is the large pillar-like fungi like Prototaxites.

Cooksonia © Nobu Tamura. Credits

In the ocean we have diversification of jawed fishes, which includes bony fish and cartilaginous fish. There is a sharp decline of jawless fish as these new ones take over.

Pictured: Eurypterus, a type of sea scorpion. Credits

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Survivability check-in:

No. There is still not enough oxygen for a big oxygen-spoiled beast such as you.

We have two main continents, Gondwanaland and Euramerica. The narrow Teays River flows through the middle of Euramerica into a shallow mid-contintental ocean where is now Indiana and Ohio. The water is quite high; most of the northern ocean is considered a super ocean named Panthalassa while plenty of smaller oceans and landmasses have thier own names.

There is evidence of highly fluctuating climate changes which is associated with several extinction events. The hardest hit were the brachiopods(bivalves), corals and trilobites.

Orthoceras © Nobu Tamura. An early nautiloid goober that graced the seas. Credits

The

Devonian

Range: 419.62 mya - 358.9 mya (60.3 my)

Known as the "Age of the Fishes",but a lot of stuff was happening on land too! We now have vascular plants with true leaves and roots, both spore-bearing and seed-bearing types! An illustrious list: clubmosses, horsetails, and progymnoperms (very early cone-bearing ancestors). These plants acted as a carbon sink, so CO2 levels dropped.

Event: Silurian/Devonian Terrestrial Revolution. This is a peak of rapid evolution where everything is diversifying quickly.

In the ocean we have the first sharks, armored fish (placoderms), the first ammonites, and lobe-finned fishes (tetrapodomorphs). These lobe-finned fishes escaped oxygen depleted waters by traveling topside to another pool and developed lungs to breathe air.

The climate is quite warm and getting warmer! The current continents are our good friend Gondwanaland to the south with Siberia to the north and Laurasia to the east.

Event: Late Devonian Extinction. This severely affected marine life. It killed most jawless fish, most placoderms, nearly all trilobites, most sponge reefs, and 96% of all vertebrates thus far. So whatever happened, it was a big deal. Curiously, land plants and freshwater species (our ancesters) were largely unaffected. There isn't a clear reason for this extinction.

Pictured: A Devonian scene © Karen Carr. Credits

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Survivability check-in:

Maybe. There were pulses in the oxygen levels during this period, maxing out at 25% which is actually a bit high uncomfy ( currently we live at 20% ). Overall it was quite warm/humid. So, if you chanced to visit it during a sweet-spot, you might survive long enough to worry about food. There you should have an array of options, mostly consisting of bugs, mollusks, ocean fish and lake fish. Since there are no advanced predators such as yourself yet, they may be easier to grab by hand than you are used to. There are some plants with which to make rudimentary tools or lean-tos, but that may be difficult. As always, there are stones. You'll also be able to eat some plants like ferns fiddleheads.

Pictured: A Carboniferous scene. Credits

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Survivability check-in:

Yes! The oxygen's a little rich though. Don't warp in during the ice age.

The

Carboniferous

Range: 358.9 mya - 298.9 mya (60 my)

The "Coal-bearing" period, and the "Age of the Amphibians and Insects". In addition to the previous animal groups, we now have amphibians, synapsids(predecessor to mammals), and sauropsids(predecessor to reptiles and birds). Also, our insects fly now! And the largest arthropod we know of, the 8ft long millipede Arthropleura, also lived gliding along the forest bed.

Our plant diversity overfloweth as well. We have horsetails, club mosses, scale trees, and early gymnosperms (cone-bearing plants). The oxygen levels fluctuate, but approach 25%-30% by the end - incredible! Note that whenever oxygen levels are high, forest fires are also rampant. And while fungi try to keep up, nobody has really perfected the recycling of plant matter yet - hence, most of our coal is the compressed remains from this period of stacked plant matter.

Extinction Event: There was a rainforest collapse caused by climte change, and towards the end of the era, there was the Late Paleozoic Ice Age (PLIA) which would become the longest ice age period to this day. It lasted 85 million years.

Pictured: Edaphosaurus. Credits

We now have cycads and ginkgos, our oldest still-present gymnosperm (cone-bearing) families. Ancient Horsetails called Calamites were actually horsetail trees and also formed forests. Many ancient tree types spread throughout the world during the late Permian.

Extinction Event: The Permian ended in what is known as The Great Dying, the largest mass extinction in earth's history (81% marine species, 70% of terrestrial species). This is attributed to the extremely large and vast eruptions of the Siberian Traps - a volcanic event that lasted 2 million years. It put the earth into a lethal global warming where equatorial ocean temps exceeded 104F. This also coincides with a coal gap since swamps and the like had dried up. It took several million years for the earth to right itself but it also shook up the playing field with new types of life emerging afterwards.

The

Permian

Range: 289.9 mya - 251.9 mya (47 my)

This is the age of mammal-like reptiles. The carboniferous rainforest collapse left behind a vast interior desert of the supercontinent Pangaea. This is why drier-skinned animals like the reptiles boomed.

Insect diversity boomed and we have all kinds of families of flying insects, they had a bit of an arms race with plants.

The land was dominated by synapsids like Dimetrodon. Take note, our mammal-like relatives were on top during this period of time, though they would look nothing like mammals. Their skull structure was simply taking familiar form and they pioneered the varying dentition which all mammals sport today.

We also have our first airborn animals besides insects - gliding lizards, with gliding membranes made from their fanned ribs. Amphibians resembled a bit like slimy lizards or salamanders of odd shapes. No frogs or anything like that yet.

The

Triassic

Range: 251.9 mya - 201.4 mya (50.5 my)

Pictured: Typothorax, an herbivorous aetosaur, a distant relative to crocodiles. Credits

The

Jurassic

Range: 201.4 mya - 143.1 mya (58.3 my)

Pictured: A Jurassic scene featuring sauropod Europasaurus, iguanadons, and smaller fauna like compsognathus, archaeopteryx, and some pterosaurs. Credits

The

Cretaceous

Range: 143.1 mya - 66 mya (77.1 my)

Pictured: Diabloceratops. Credits

The

Paleogene

Range: 66 mya - 23 mya (43 my)

Pictured: Eocene scene featuring Patriofelis, Pristichampsus, Hyrachyus, Orohippus. Credits

The

Neogene

Range: 23 mya - present (23 my)

Pictured: Woolly Mammoth. Credits