🧾 Summary Table

Level	Units	Mnemonic
	Big Bang, Supernova, Star Formation	Big Super Star
Eons	Hadean, Archean, Proterozoic, Phanerozoic	Happy
Eras	Paleozoic, Mesozoic, Cenozoic	Put My Cake
Paleozoic Periods	Cambrian → Permian	Come On Stupid Don’t Cause Problems
Mesozoic Periods	Triassic → Cretaceous	Try Just Caring
Cenozoic Epochs	Paleocene → Holocene	Put Egg On My Plate Please Honey

Eons	Era	Period	Epoch	Age/Years Before Present	Life/Major Events	More Details
Phanerozoic	Cainozoic	Quaternary	Holocene	0 - 10,000	Modern Man	Development of civilizations, agriculture, writing, industrialization, and digital technology. Climate stabilizes post-Ice Age.
			Pleistocene	10,000 - 2 million	Homo Sapiens	Ice Ages dominate; Homo sapiens evolve and spread from Africa; coexistence with other hominins (e.g., Neanderthals); megafauna extinctions.
		Tertiary	Pliocene	2 - 5 million	Early Human Ancestor	Hominins diversify (e.g., Australopithecus); global cooling trend continues; grasslands expand; North and South America connect.
			Miocene	5 - 24 million	Ape: Flowering Plants and Trees	Apes and monkeys diversify; forests decline as grasslands expand; ancestors of modern animals appear.
			Oligocene	24 - 37 million	Anthropoid Ape	First monkeys in South America due to continental drift; Antarctic ice sheet forms; mammal evolution accelerates.
			Eocene	37 - 58 Million	Rabbits and Hare	Warm global climate; early whales and horses; diversification of mammals; modern plant families appear.
			Palaeocene	57 - 65 Million	Small Mammals: Rats - Mice	Mammals begin rapid diversification post-dinosaur extinction; first large mammals; forests cover most land.
	Mesozoic	Cretaceous		65 - 144 Million	Extinction of Dinosaurs	Flowering plants (angiosperms) spread; ends with mass extinction (asteroid impact); birds evolve from dinosaurs.
		Jurassic		144 - 208 Million	Age of Dinosaurs	Dinosaurs diversify; first birds; conifers dominate plant life; early mammals remain small and nocturnal.
		Triassic		208 - 245 Million	Frogs and turtles	First true dinosaurs and mammals appear; Pangaea starts to break apart; mass extinction ends period.
	Palaeozoic	Permian		245 - 286 Million	Reptile dominate-replace amphibians	Supercontinent Pangaea fully formed; dry climate; mass extinction at end (over 90% of marine species gone).
		Carboniferous		286 - 360 Million	First Reptiles: Vertebrates: Coal beds	Dense forests; high oxygen levels; giant insects and amphibians; coal-forming swamps dominate.
		Devonian		360 - 408 Million	Amphibians	Age of Fishes; first tetrapods (land vertebrates); early forests; ammonites appear.
		Silurian		408 - 438 Million	First trace of life on land: Plants	First vascular land plants; jawed fish appear; primitive insects and arachnids begin terrestrial colonization.
		Ordovician		438 - 505 Million	First Fish	First vertebrates (jawless fish); diverse marine invertebrates; early land plants and arthropods colonize shorelines.
		Cambrian		505 - 570 Million	No terrestrial Life: Marine Invertebrate	Cambrian Explosion: sudden emergence of complex life; first arthropods, mollusks, and echinoderms.
Proterozoic		Pre-Cambrian		570-2,500 Million	Soft-bodied arthropods	Evolution of multicellular life; Ediacaran fauna emerge; oxygen accumulates in atmosphere; eukaryotic cells evolve.
Archean				2,500-3,800 Million	Blue green Algae: Unicellular bacteria	Photosynthetic cyanobacteria release oxygen; Great Oxidation Event (~2,400 Mya); prokaryotic life dominates.
Hadean				3,800 - 4,800 Million	Oceans and Continents form - Ocean and Atmosphere are rich in CO₂	Formation of Earth (~4,600 Mya); molten surface cools; formation of crust, oceans, and primitive atmosphere; no life yet.
		Origin of Stars		~5,000 Million	Origin of the sun	Sun and solar system form from interstellar gas cloud; planets begin forming through accretion.
		Supernova		~12,000 Million		Heavy elements like carbon, iron, and gold formed in massive star explosions; seeded the solar system.
		Big Bang		~13,700 Million	Origin of the universe	Space, time, matter, and energy emerge; universe begins expanding; hydrogen and helium form; cosmic background radiation appears about 380,000 years later.