Phanerozoic EON
(544 mya to present)

Evolutionary Milstones

Cenozoic Era
(65 mya to today)

Quaternary (1.8 ma to today)

Holocene (11,000 years to today) Modern man radiates, "science" appears and eventually computers and the Internet become ubiquitous.
Pleistocene (1.8 mya to 11,000 yrs) Neandertals appears and disappear; Homo erectus and Homo sapiens appear
Pliocene (5 to 1.8 mya) Ape-like ancestors of modern humans (Hominids), the Australopithecines
Columbian copal is thought to have formed.
Tertiary (65 to 1.8 mya) Miocene (23 to 5 mya) Grazing horses, antelopes appear -
Oligocene (38 to 23 mya)

Radiation of more modern animals: most modern bird forms have appeared; most modern mammals have appeared.
Dominican amber is formed

Eocene (54 to 37 mya) First grasses appear, a resource for herbovores; trees thrive. Some modern mammals appear: advanced primates; camels, cats, dogshorses & rodents
Paleocene (65 to 54 mya) Flowering plants begin radiation extending through the Eocene. Small mammals radiate
Mesozoic Era
(245 to 65 mya)

Cretaceous (146 to 65 mya)





Major extinction includes dinosaurs and ammonites (K-T)
Appearances include: flowering plants (angiosperms); lizards; placental animals (early mammals); snakes; social insects; marsupial and placental animals
Modern insect forms radiate

Jurassic (208 to 146 mya) Appearances include: birds; crabs; frogs and salamanders
Dinosaurs radiate to dominate the land
Triassic (245 to 208 mya) Major extinction event: tabulate corals and conodonts disappear - ammonoids, reptiles and amphibians decimated
Appearances include: dinosaurs; crocodiles; marine reptiles; turtles and mammals
Major groups of seed plants appear


Paleozoic Era
(544 to 245 mya)

Permian (286 to 245 mya)

Major extinction of invertebrates (P-T). Trilobites fade away forever. All but articulate crinoids dissapear
Seedplants producing large trees

(360 to 286 mya)
Pennsylvanian (325 to 286 mya) Conifers & many winged insects appear
Mississippian (360 to 325 mya) Reptiles appear. Trilobites become scarce
Devonian (410 to 360 mya) Mass extinction (F-F)
Appearances include: insects; sharks; amphibians (tetrapods); lung fishes and earliest seed plants
Silurian (440 to 410 mya) Jawed fish, cartilaginous fish and vascular plants appear.
Ordovician (500 to 440 mya)
Mass extinction
First land plants; bryozoans appear. Trilobites begin to specialize.
Cambrian (544 to 500 mya) Tommotian (530 to 527 mya) Appearance of hard parts - fossils become common. Appearances include: vertebrates; jawless fish; small shelly animals; conodonts; trilobites radiate repeatedly and reach their peak diversity. First major radiation of animals


Precambrian Time
(4,500 to 544 mya)

Proterozoic Era
(2500 to 544 mya)
Vendian (650 to 544 mya) or Ediacaran
No Epochs

Extinction at end of Vendian
Macroscopic fossils of soft-bodied organisms.

Oldest metazoans (multicellular animals) - Ediacaran Fauna.

Neoproterozoic (900 to 544 mya) - Late

Macroscopic fossils of soft-bodied organisms.
Stromatolite diminishes

Mesoproterozoic (1600 to 900 mya) - Middle Sexual reproduction appears (about 1 billion years ago)
Paleoproterozoic (2500 to 1600 mya) - Early Eukaryotic cells appear (1.6 BYA) - aerobic
Peak of stromatolite with cyanobacteria oxygenating the atmosphere

(3800 to 2500 mya)

First life appears - Heterotrophic, anerobic, prokaryotic, Asexual
Oldest fossils - Apex Chert of Australia (3.55 BYA) - simple cell forms and stromatolite

Oldest sedimentary rocks (3.8 BYA)

(4500 to 3800 mya)
Earth's environment extremely hostile to life as we know it