|
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 |
