| EON |
ERA |
PERIOD |
EPOCH |
PIVOTAL EVENTS |
P
h
a
n
e
r
o
z
o
i
c
E
o
n
"Visible Life"
Organisms with skeletons or hard
shells.
540 mya through today.
P
h
a
n
e
r
o
z
o
i
c
E
o
n
"Visible Life"
Organisms with skeletons or hard
shells.
540 mya through today.
P
h
a
n
e
r
o
z
o
i
c
E
o
n
"Visible Life"
Organisms with skeletons or hard
shells.
540 mya through today.
P
h
a
n
e
r
o
z
o
i
c
E
o
n
"Visible Life"
Organisms with skeletons or hard
shells.
540 mya through today. |
Cenozoic Era
"The Age
of Mammals"
65 mya through today |
Quaternary
Period
"The Age of Man"
1.8 mya to today |
Holocene
11,000 ya to today |
Human civilization |
Pleistocene
The Last Ice Age
1.8-.011 mya |
The first humans (Homo
sapiens) evolve.
Mammoths, mastodons,
saber-toothed cats, giant ground sloths, and other
Pleistocene megafauna. A mass extinction of large
mammals and many birds happened about 10,000 years ago,
probably caused by the end of the last ice
age. |
Tertiary Period
65 to 1.8 mya |
Neogene
24-1.8 mya |
Pliocene
5-1.8 mya |
First hominids (australopithecines). Modern forms of whales.
Megalodon swam the seas |
Miocene
24-5 mya |
More mammals, including the horses, dogs and bears. Modern
birds. South American monkeys, apes in southern Europe,
Ramapithecus. |
Paleogene
65-24 mya |
Oligocene
38-24 mya |
Starts with a minor extinction (36 mya).
Many new mammals (pigs,
deer,
cats, rhinos, tapirs appear).
Grasses common. |
Eocene
54-38 mya |
Mammals abound. Rodents appear.
Primitive whales appear. |
Paleocene
65-54 mya |
First large mammals and primitive
primates,
plesiadapiforms. |
Mesozoic Era
"The
Age of Reptiles"
248 to 65 mya |
Cretaceous Period
146 to 65 mya
 |
Upper
98-65 mya |
High tectonic and volcanic activity.
Primitive marsupials develop. Continents have a modern-day
look. Minor extinction 82 mya. Ended with
large extinction (the
K-T extinction) of dinosaurs,
pterosaurs,
ammonites, about 50 percent of marine invertebrate
species, etc., probably caused by
asteroid impact or volcanism. |
Lower
146-98 mya |
The heyday of the dinosaurs. The first crocodilians, and
feathered dinosaurs appear. The earliest-known
butterflies appear (about 130 million years ago) as well as
the earliest-known snakes, ants, and bees. Minor extinctions
at 144 and 120 mya. |
Jurassic Period
208 to 146 mya
 |
Many dinosaurs, including the giant
Sauropods. The first birds appear (Archaeopteryx).
The first
flowering plants evolve. Many ferns, cycads, gingkos,
rushes, conifers,
ammonites, and
pterosaurs. Minor extinctions at 190 and 160 mya. |
Triassic Period
248 to 208 mya
 |
The first
dinosaurs, mammals, and
crocodyloformes appear. Mollusks are the dominant
invertebrate. Many reptiles, for example, turtles,
ichthyosaurs. True flies appear. Triassic period ends
with a minor extinction 213 mya (35% of all animal families
die out, including labyrinthodont amphibians, conodonts, and
all marine reptiles except ichthyosaurs). This allowed the
dinosaurs to expand into many niches. |
Paleozoic Era
540 to 248 mya
Paleozoic Era
540 to 248 mya |
Permian Period
"The Age of Amphibians"
280 to 248 mya
 |
"The Age of Amphibians" -
Amphibians and reptiles dominant. Gymnosperms dominant
plant life.The continents merge into a single
super-continent,
Pangaea. Phytoplankton and plants oxygenate the Earth's
atmosphere to close to modern levels. The first stoneflies,
true bugs, beetles, and caddisflies, The Permian ended with
largest mass extinction. Trilobites go extinct, as do
50% of all animal families, 95% of all marine species, and
many trees, perhaps
caused by glaciation or volcanism. |
Carboniferous
Wide-spread
coal swamps, foraminiferans, corals, bryozoans,
brachiopods, blastoids, seed ferns, lycopsids, and other
plants. Amphibians become more common.
360 to 280 mya |
Pennsylvanian Period
325 to 280 mya |
First reptiles. Many ferns. The first
mayflies and cockroaches appear. |
Mississippian Period
360 to 325 mya |
First winged insects. |
Devonian Period
"The Age of Fishes"
408 to 360 mya
 |
Fish and land plants become abundant and diverse. First
tetrapods appear toward the end of the period. First
amphibians appear. First sharks, bony fish, and
ammonoids. Many
coral reefs, brachiopods,
crinoids. New insects, like springtails, appeared.
Mass extinction (345 mya) wiped out 30% of all animal
families) probably
due to glaciation or meteorite impact. |
Silurian Period
438 to 408 mya |
The first jawed fishes and
uniramians (like
insects, centipedes and millipedes) appeared during the
Silurian (over 400 million years ago). First
vascular plants (plants with water-conducting tissue as
compared with non-vascular plants like mosses) appear on
land (Cooksonia is the first known). High seas worldwide.
Brachiopods,
crinoids,
corals. |
Ordovician Period
505 to 438 mya |
Primitive plants appear on land. First
corals. Primitive fishes, seaweed and fungi. Graptolites,
bryozoans, gastropods, bivalves, and echinoids. High sea
levels at first, global cooling and glaciation, and much
volcanism. North America under shallow seas. Ends in
huge extinction, due to
glaciation. |
Cambrian Period
"The
Age of Trilobites"
540 to 500 mya
 |
"Age of
Trilobites" -The
Cambrian Explosion of life occurs; all existent phyla
develop. Many marine invertebrates (marine animals with
mineralized shells: shell-fish,
echinoderms,
trilobites, brachiopods,
mollusks, primitive graptolites). First vertebrates.
Earliest primitive fish. Mild climate. The supercontinent
Rodinia began to break into smaller continents (no
correspondence to modern-day land masses).
Mass extinction of trilobites and nautiloids at end of
Cambrian (50% of all animal families went extinct), probably
due to glaciation.
|
Proterozoic Eon
2.5 billion years ago to
540 mya |
- |
Vendian Period
600 to 540 Million Years Ago |
Vendian biota (Ediacara fauna) multi-celled animals
appear, including
sponges. A
mass extinction occurred. The continents had merged into
a single supercontinent called Rodinia. |
|
- |
First multicellular life: colonial
algae and soft-bodied invertebrates appear.
Oxygen build-up in the Mid-Proterozoic. |
Archeozoic Eon
(Archean)
3.9 to 2.5 billion years ago |
- |
- |
"Ancient Life" - The first life forms
evolve - one celled organisms. Blue-green algae,
archaeans, and
bacteria appear in the sea. This begins to free oxygen
into the atmosphere. |
Hadean Eon
4.6 to 3.9 billion years ago |
- |
- |
"Rockless
Eon" - The solidifying of the Earth's continental and
oceanic crusts |
