|
Phanerozoic
EON
(541 mya - present)
"The
age of visible life"
|
ERA
|
Periods
|
Epoch
|
Evolutionary
Milestones
|
|
(65
mya - today) |
Quaternary
(2.6
mya - today) |
Holocene
(11 kya - today) |
Modern
man radiates, "science" appears and eventually computers
and the Internet and Iphones become ubiquitous.
Plants and
animals domesticated at ~ 13 kya. Mass extinction ongoing due to Man. |
Pleistocene
(2.6
mya - 11K)
|
Neandertals
appear and disappear; Homo erectus and Homo sapiens appear; Homo sapien
speech attained at ~ 75kya. Stone age commences with a human extinction
near miss do to continuing ice age. |
|
|
Ape-like
ancestors of modern humans (Hominids), the australopithecines, as well
as Homo habilis appear. Land and marine animals including mammals generally
modern. Cooler & drier climate reduces tropical plants as deciduous
& coniferous
forests as well as grasslands & savannas expand. |
|
Expansive
grasslands formed giving rise to new mammal forms, especially grazing
horses, rhinoceros, camels, & antelopes, & of course their predators. Many
primates & 1st bipedal apes. Mastodons (megafauna) appear late
in epoch.
Some 95% of plants are extant today; almost all extant bird families
present by epoch end, as well as about half of modern invertebrates.
Marine vertebrates diversify; whales reaching their maximum.
In the seas, vast proliferating kelp and algae fosters new vertebrate
and higher mammals (seals), marine life species & associated apex
predators like megalodon sharks.
|
|
|
Evolution
of more modern animals continued, particularly among mammals (1st
seals) and among angiosperms. Most modern bird forms present.
Grazers adapt to apex predators like the saber-toothed cat with
longer legs and speed. Oreodonts herebivores abundant.
|
|
Eocene
ends with extinction event.
First grasses appear, a resource for herbovores;
trees thrive.
Most extant placental mammals appear: modern camels, cats, dogs,
horses & rodents & 1st true primates; 1st whales and sea cows.
Earth covered with forests, with rain forests in North America turning
to deciduous trees over epoch.
Snakes and turtles abundant and many new avian orders arise.
Insects abundant and appear modern.
Cartilaginous and ray-finned fish thrive worldwide. |
|
|
Flowering
plants (angiosperms begin radiation extending through the Eocene, fostered
by appearance and co-evolution with bees. Small mammals radiate. |
|
|
(145
- 65 mya)
|
Upper
(100
- 66 mya)
|
Ends
with Cretaceous - Tertiary
(K–T) extinction event. Major
extinctions include non avian dinosaurs and ammonites Some 17% of
families, 50% of genera and 75% of species disappaer.
Tyrannosaurus and Mosasaurs appear
late.
|
|
| Lizards;
placental animals (early mammals); Also appearing: snakes; social marsupial
and primitive placental animals.
New insect forms appear and radiate, including social
Hymenopterans.
Pterosaurs
common, then decline; Archosaur
reptiles
and dinosaurs small to huge apex predators common on land, and Chondrichthyes
and
Actinopterygii
fishes in the seas diversify.
|
|
|
| Large
theropod predators such as Allosaurus Ceratosaurus
& Megalosaurus.
Archaeopteryx transitional bird fossil from Solnhofen.
Archosaurian
reptiles dominate the land through Jurassic, including herbivorous
sauropods (Camarasaurus, Apatosaurus, Diplodocus, Brachiosaurus).
Earliest
flowering plants (angiosperms) appear at ~ 160 mya or earlier...
Other
appearances
include birds; crabs; frogs and salamanders.
Dinosaurs
radiate to dominate the land. |
|
| Pangaea
begins to separate into Laurasia and Gondwana & Atlantic Ocean
forms.
First salamanders
Herbivorous
Stegosauria & Brachiosaurus & Carnosauria theropod dinosaurs appear.
Conifers dominated the land.
Plesiosaurs became common. |
|
| Appearances
include Pliosaurs, birds;
crabs; frogs salamanders & lepidopterans.
Breakup of Pangaea begins.
First Ginkophyta.
|
|
|
| Extinction
even at ~ 200 mya killed some 23% of all families, 48% of all genera
(20% of marine families and 55% of marine genera) and 70% to 75%
of all
species
went extinct.
First flowering plants.
Major extinction event: tabulate corals and conodonts disappear
- ammonoids, reptiles and amphibians decimated
Appearances include: dinosaurs (early theropods); crocodiles; marine
reptiles; turtles; Pterosauria and
mammals; Dermaptera insects.
Major new groups of seed plants appear.
|
|
| First termites and
flies.
Early
small dinosaurs like Nyasasaurus appears.
|
|
| Radiation
of planktonic organisms in lower food chain.
Ichthyosaurs &
belemite cephalopods appear.
Recovery slow from P-T extinction due to low faunal & floral diversity.
Tetrapoda would take some 30 my to recover.
|
|
(541 - 252 mya) |
|
Lopingian
(259
- 252 mya)
|
The
great dying, the Permian-Triassic (P-T) extinction event at 251
mya eradicates 95% of all life, though most plants minimally affected.
Blastoids & remaining Proetid Trilobites;
all but articulate crinoids dissapear forever.
|
Guadalupian
(272
- 252 mya)
| Seed
plants are producing large trees.
Insect order Hemiptera.
The primitive amniotes radiate into ancestors of lizards, mammals, turtles,
lizards
and
archosaurs. |
Cisuralian
(299
- 272 mya)
| ~
10 miilion years for life to recover from P-T extinction.
First cycad seed plants. |
(359 -
299 mya)
"Age of Coal"
|
Pennsylvanian
(323
- 299 mya)
| 1st
Conifers near end of epoch.
Diverse and common amphibians give rise to 1st reptiles
(possibly amniotic) at ~ 315 mya - reptiles become dominant tetrapods
by end
of epoch.
Dense coal forests form, comprising scale trees, ferns, club trees,
tree ferns, giant horsetails, cordaites.
Major
radiation of
winged insects. First beetles (Coleoptera) and
dragonflies (Odonata).
Hexapod
arthropods large, diverse, and the primary forest herbivores.
|
Mississippian
(359 - 323
mya)
| High
diversity of marine
life across brachiopods, bryozoans, echinoderms
fishes, mollusks,
and .
Land plants divide with seed plants to drier areas and lycopods to
wetter areas.
Amniotic
eggs appear.
Trilobites become
scarce.
|
(419
- 359 mya)
"Age of Fishes"
|
| Mass
extinction (F-F) lasting 20 my from ~ 375 mya killed some 19% of all
families, 50% of all genera and 70% of all species.
Plants
seeds evolved.
Land colonized by plants and animals. Appearances include: insects; sharks;
amphibians (tetrapods);nd the earliest seed plants. Extensive
radiation of fishes.
Rhizodont predatory lobe-finned
fishes appear at ~ 377 mya & dominate fresh water well into Pennsylvanian. |
|
| Plants
fundamentally recognizable as today, with roots, leaves and
wood at. |
|
| First
lungfish.
First unequivocal insect fossil at ~ 396 mya.
First ammonites at ~ 400 mya.
|
|
| First
insects probable.
First
Arachnids
(Trigonotarbida). Definitive Age of Fishes:
Lobe-finned
fish, the Sarcopterygii, at ~ 418 mya. Ray finned fish
(Actinopterygii)
appear ~ 420 mya & Cartilaginious
fish, the Chondrichthyes, appaer at ~ 422 mya.
Many primitive terrestrial
predators. |
|
| Vascular
plants appear Cooksonia.
Eurypterids, the largest arthropods that ever lived, appear and become
common marine predators. |
|
| Placoderms appear
at ~ 430 mya.
First millipede one of earliest terretrial animals. |
Llandovery
(443 - 433 mya)
| Acanthodii
(spiny sharks) appear
at ~ 430 mya.i
Supercontinent Gondwana covers equatorial
Earth. |
(485 - 443
mya)
"Great Ordovician Radiation" |
Upper
(458 - 443 mya)
| Mass
extinction
event from ~ 450 mya laster 10 my, killing 27% of families, 57% of
genera & 70% of species.
Vascular
plant spores.
Bryozoans appear & trilobites begin
to specialize.
Stromatolites become
rare & mostly replaced by complex reef systems. |
|
Middle
(470 - 458 mya)
| First
non-vascular land plant spores at ~ 460 mya or earlier,
Trilobites brachiopods, molluscs cephalopods and other mollucs, crinoids
and other echinoderms, graptolites,
cnidarians.
Evidence of first jawed fish, the Gnathostomata at
~ 460 mya. |
|
Lower
(485 - 470 mya)
| Commences
with the great Ordovician radiation (Ordovician explosion), as life
recovers
from the Cambrian – Ordovician
extinction event (488 mya). Diversity eventually far exceeded that of
the Cambrian.
Trilobite Order Phacopida appears.
|
(541
- 485 mya)
"Cambrian Explosion"
|
Furongian
(497 -
485 mya)
| Cambrian – Ordovician
event ended the Cambrian Period, where many brachiopods
and conodonts perished, and trilobites were severely reduced.
First Nautilods at ~ 495 mya.
First cephalopods & gastropods and Asterozoa (starfish & brttle stars) |
Series
3
(509
- 497 mya)
| Appearances
include: vertebrates fish; small shelly animals mostly extinct
by end of early Cambrian (End-Botomian mass extinction); conodonts; trilobites radiate
repeatedly and reach their peak diversity. |
Series
2
(521
- 509 mya)
| Primitive
plant forms evolved from green algae.
Numerous mollusc forms such as Bivalvia appear through Cambrian,
especially late, though phylogeny controversial, with conjecture
for affinity
to Ediacaran
organisms. |
Terreneuvian
(541
- 521 mya)
| End-Botomian
mass extinction from ~ 524 - 517 mya.
Cambrian
Explosion, the
1st major radiation of animals when most phyla appear. Appearance
of hard parts and vision - macroscopic fossils become common.
Early chordate Haikouella,
and putative fish Haikouichthys and Myllokunmingia from Chengjiang
Biota @ ~ 525 mya.
Echinoderms such
as Crinozoa appear, likely from Ediacaran progenitprs.
First jawless
fish, the Agnatha, at ~ 530 mya. |
|
(2500-541 mya) |
Neoproterozoic
(1000
- 541 mya)
Late
|
Ediacaran or
Vendian
(635
- 541 mya)
|
Extinction
at end of Ediacaran.
Appearance of Tommotian mineralized
Fauna (small shelly animals)at ~ 550 mya: they radiate
worldwide.
Macroscopic, soft-bodied organisms radiating, the oldest metazoan (multicellular
animals) - fossils known as the Ediacaran
Biota, including trilobitamorphs, poriferans and other enigmatic
forms.
|
|
Stromatolites diminishing
further, possibly providing food for herbivorous eukaryotes.
|
Cryogenian
(850
- 635 mya)
|
|
|
Chloroblasts
arise from cyanobacteria through endosymbiosis at
~ 1000 mya.
Acritarchs radiate, becoming widespread & some
perhaps eukaryotic and photosynthetic dinoflagellates or eukaryotic
protists. |
Mesoproterozoic
(1600
- 1000 mya)
Middle
|
Stenian
(1200
- 1000 mya)
|
Rodinia
supercontinent forms at ~ 1000 mya, setting stage - its breakup at
700 mya have played a role in the Cambrian
Explosion. |
Ectasian
(1400
- 1200 mya)
|
Colonial
green algae flagellates cover the seas; these photosynthetic eukaryotic
organisms are basal to vascular land plants to come. |
Calymmian
(1600
- 1400 mya)
|
Free
atmospheric
oxygen build-up continues desimating some prokaryotic bacteria, but
enabling replacement by newly evolved eukaryotic forms,
including photosynthetic multicellular algae. |
Paleoproterozoic
(2500
- 1600 mya)
Early
|
Statherian
(1800
- 1600 mya)
|
The
"Boring Billion" years of evolutionary stasis begins.
More
complex single-celled life with aerobic metabolism begin diversification.
Eukaryotic
mitochondria evolve.
Approximate peak of stromatolites with
cyanobacteria oxygenating the atmosphere.
Fossilized filamentous algae (eukaryote)
at ~ 1700 mya.
|
Orosirian
(2050
- 1800 mya)
|
Banded
iron formation diminishes allowing atmosphere to oxygenate rapidly,
reaching ~ 15% at ~ 1800 mya. |
Rhyacian
(2300
- 2050 mya)
|
The
oldest known potential multicellular eukaryote is Grypania spiralis,
appearing as a coiled algae in 2100 mya banded iron formations in Michigan.
Earliest known single-celled eukaryote fossils are acritarchs, which
become widespread at ~ 2100 mya. acritarchs
are most common fossils of late Proterozoic. |
Siderian
(2500
- 2300 mya)
|
Banded
iron formation accelerates at ~ 2400 mya, continuing at high rate until
diminishing at ~ 1800 mya -- the rusting of the seas commences. |
|
(4000-2500
mya) |
Neoarchean
(2800 - 2500 mya)
|
Molecular
fossils from
Australia
suggest eukaryotes appeared at ~ 2700 mya, but this is not a widely
accepted view, with other estimates at ~ 3500 mya.
Atmospheric oxygen only ~ 1%.
|
Mesoarchean
(3200 - 2800 mya)
|
Prokaryotes
dominate (Eubacteria
and Archaea); simple cell forms generate extensive stromatolite reef
systems. First acritarch microscopic fossils.
1st substantial free oxygen from photosynthetic archaea and bacteria
at ~ 3000 to 2300 mya, after which free oxygen produced by these prokaryotes
combined with dissolved iron in the oceans to form banded
iron formations until ~ 2000 to 1300 mya -- the
so-called rusting of the Earth.
Oldest life of Earth evidence that is not contested at ~ 3000 mya. |
Paleoarchean
(3600 - 3200 mya)
|
Primitive Eukaryotes as
early as ~ 3500 mya after endosymbiosis.
Oxygenic photosynthetic cyanobacteria appear ~ 3500 mya.
Oldest
fossils - Apex Chert at ~ 3550 mya & Strelly Pool
at ~ 3430 mya in Pilbara, Western Australia
|
Eoarchaean
(4000 - 3600
mya)
|
First
banded iron formation at ~ 3700 mya.
Oxygenic
photosynthetic prokaryotic bacteria appear at ~ 3500 mya.
Putative first appearance of life,
at ~ 3800 mya & is Archaea
or Bacteria, chemotrophic, anerobic, asexual, prokaryotes,
fairly soon after end of earth bombardment - no consensus for this geochemical-based
evidence.
Oldest sedimentary rocks ~ 3800 mya.
Earth's crust cooled by ~ 4000 mya, but atmosphere comprised volcanic
gases and minimal oxygen.
The 1st oceans were formed.
|
|
(4567-4000
mya) |
Lower
Imbrian
(4100 - 4000 mya)
|
Self
replicating RNA molecules may might have appeared at ~ 4000 mya.
Late heavy bombardment from space ends at ~ 4000 mya ends, setting stage
for life to appear.
Earth's oldest surviving rock from Canada dated at ~ 4030 mya. |
Nectarian
(4300
- 4100 mya)
|
Nectarian
begins with so-called Late Heavy Bombardment of Earth from space.
Crust formation continuing through Hadean, as does mountain building. |
Basin
Groups
(4500
- 4300 mya)
|
Name
derived from groupings of major lunar impact crators.
Water begins building in atmosphere.
As outer layer of Earth cools to thin crust, constantly disrupted by
impacts. |
Cryptic
(4567
- 4500 mya)
|
Earth's
environment exceedingly hostile to life as we know it.
Meager geological evidence survives from this time, having been destroyed
by bombardment of earth from space projectiles, including the one that
putatively formed the moon.
Earth forms at ~ 4567 mya. Moon forms ~ 4533 mya due to some huge impact.
Earth essentially molten owing to volcanism and space collisions.
Solar system forming ~ 4600 mya.
|
