Table 1: Timeline of Life
Era	Period	Epoch	Years Ago	Event	Notes
			13.7bn	Universe Born
			4.5bn	Earth Born
Archean			4bn-2.5bn	Bacteria appeared on Earth 3.5bn ya
Paleoproterozoic			2500-1600m
Mesoproterozoic			1600-1000m
Neoproterozoic			1000-541m	First multicellular organisms 600m ya
Paleozoic	Cambrian		541m-485m
	Ordovician		485m-444m
	Silurian		444m-419m
	Devonian		419m-359m		First fish like four limbed animals evolved in the Devonian period. These creatures were the ancestors of amphibians and ultimately reptiles, birds and mammals.
	Carboniferous		359m-299m
	Permian		299m-252m	Permian-Triassic Extinction event (Great Dying) 252m years ago	Permian-Triassic Extinction event, worst mass extinction in history when mega volcanoes in Siberia spewed lava and CO2 for millions of years, causing a global heat spike that killed off up to 95% of all species.
Mesozoic	Triassic	Early Triassic	252-247m	Dinosaurs first appeared 247-240m ya	Triassic-Jurassic extinction event marks beginning of Jurassic period
		Middle Triassic	247-237m
		Late Triassic	237-201m
	Jurassic	Early Jurassic	201-174m
		Middle Jurassic	174-164m
		Late Jurassic	164-145m	Archaeopteryx appeared 150m ya (widely regarded as first bird) Earliest Tyrannosaurids appeared around 155m years ago and include Guanlong which measured 9 feet long.
	Cretaceous	Early Cretaceous	145-100m
		Late Cretaceous	100-65.5m	T-Rex (40-43 feet long) lived between approx 68 and 66m years ago.
			65.5mn	Cretaceous-Paleogene (K-Pg) extinction event. Extinction of non-avian Dinosaurs
Cenozoic	Paleogene		66-23m ya		Mammals endured the Cretaceous–Paleogene extinction event and persevered during the next 10 million years setting the foundation for the 6,000 species of placental mammals that thrive today.
	Neogene		23-2.59m ya	First human ancestors (Hominin) appeared 5-7m ya	predates earliest humans in the homo genus
				Kenyanthropus platyops lived 3.3-3.2m ya
				Oldest stone tools discovered in 2015 from 3.3m ya
				Australopithecus afarensis lived 3.9-2.9m ya	Lucy fossil 3.66m years old
	Quaternary	Pleistocene(Ice Age)	2.58m-11.57K ya	Homo habilis lived 2.3-1.65m ya	Was thought to be earliest ancestor in the homo genus to use tools but now debunked.
				Homo erectus lived 1.89m ya-110,000ya	First of our ancestors to develop shorter arms and longer legs.
				Homo heidelbergensis lived 700,000-200,00ya	First humans to live in cold climates and hunt large animals. Evolved into two separate species - neanderthals and sapiens.
				Homo neanderthalensis lived 400,000-40,000ya	Shorter and stockier than us, brain as large if not larger. Widely thought that H.heidelbergensis was ancestor.
				Homo naledi lived 335,000-235,000ya	Anatomy suggests it walked on two legs but could climb and hang from trees
				Denisovan lived 300,000-15,00-ya	lack of fossil material, overlapped and interbred Neanderthals and Homo sapiens
				(highly uncertain)
				First homo-sapiens appeared 300,00ya	Ancestor was H.heidelbergensis.
				Homo floresiensis lived 190,000-50,000ya	nick named the hobbit people, small but capable. Likely ancestor was H.erectus.
				Homo luzonensis lived ? to 50,000ya	Blend of ancient and modern features. Likely ancestor was H.erectus.
				Dogs first domesticated 50,000-14,000ya	Undisputed remains 14,200ya
		Holocene	11.57K-0 ya	Modern Homo-sapiens	The naked ape, unable to control immediate gratification and desires, over consumes the Earths resources, pollutes the environment it depends on with litter and plastic, rejecting all responsibility.