Evolutionary Timeline

Evolutionary Timeline

Time

Event

seconds in a day

1 My = seconds

Time

(Myr ago)

86400

#

18.78261

4600

Formation of the approximately homogeneous solid Earth by planetesimal accretion

0

12:00:00 AM

4300

Melting of the Earth due to radioactive and gravitational heating which leads to its differentiated interior structure as well as outgassing of molecules such as water, methane, ammonia, hydrogen, nitrogen, and carbon dioxide

5634.8

0.065217

1:33:55 AM

4300

Atmospheric water is photodissociated by ultraviolet light to give oxygen atoms which are incorporated into an ozone layer and hydrogen molecules which escape into space

0

4000

Bombardment of the Earth by planetesimals stops

11270

0.130435

3:07:50 AM

3800

The Earth's crust solidifies--formation of the oldest rocks found on Earth

15026

0.173913

4:10:26 AM

3800

Condensation of atmospheric water into oceans

0

3500-2800

Prokaryotic cell organisms develop

20661

0.23913

5:44:21 AM

3500-2800

Beginning of photosynthesis by blue-green algae which releases oxygen molecules into the atmosphere and steadily works to strengthen the ozone layer and change the Earth's chemically reducing atmosphere into a chemically oxidizing one

33809

0.391304

9:23:29 AM

2400

Rise in the concentration of oxygen molecules stops the deposition of uraninites (since they are soluble when combined with oxygen) and starts the deposition of banded iron formations

41322

0.478261

11:28:42 AM

2000

The Oklo natural fission reactor in Gabon goes into operation

48835

0.565217

1:33:55 PM

1600

The last reserves of reduced iron are used up by the increasing atmospheric oxygen--last banded iron formations

56348

0.652174

3:39:08 PM

1500

Eukaryotic cell organisms develop

58226

0.673913

4:10:26 PM

1500-600

Rise of multicellular organisms

75130

0.869565

8:52:10 PM

580-545

Fossils of Ediacaran organisms are made

75506

#

0.873913

8:58:26 PM

545

Cambrian explosion of hard-bodied organisms

76163

0.881522

9:09:23 PM

528-526

Fossilization of the Chengjiang site

76483

#

0.885217

9:14:43 PM

517-515

Fossilization of the Burgess Shale

76689

#

0.887609

9:18:09 PM

500-450

Rise of the fish--first vertebrates

77009

#

0.891304

9:23:29 PM

430

Waxy coated algae begin to live on land

78323

0.906522

9:45:23 PM

420

Millipedes have evolved--first land animals

78511

0.908696

9:48:31 PM

375

The Appalachian mountains are formed via a plate tectonic collision between North America, Africa, and Europe

79357

0.918478

10:02:37 PM

375

Appearance of primitive sharks

79357

0.918478

10:02:37 PM

350-300

Rise of the amphibians

79826

#

0.923913

10:10:26 PM

350

Primitive insects have evolved

79826

0.923913

10:10:26 PM

350

Primitive ferns evolve--first plants with roots

79826

0.923913

10:10:26 PM

300-200

Rise of the reptiles

80765

#

0.934783

10:26:05 PM

300

Winged insects have evolved

80765

0.934783

10:26:05 PM

280

Beetles and weevils have evolved

81141

0.93913

10:32:21 PM

250

Permian period mass extinction

81704

0.945652

10:41:44 PM

230

Roaches and termites have evolved

82080

0.95

10:48:00 PM

225

Modern ferns have evolved

82174

0.951087

10:49:34 PM

225

Bees have evolved

82174

0.951087

10:49:34 PM

200

Pangaea starts to break apart

82643

0.956522

10:57:23 PM

200

Primitive crocodiles have evolved

82643

0.956522

10:57:23 PM

200

Appearance of mammals

82643

0.956522

10:57:23 PM

145

Archaeopteryx walks the Earth

83677

0.968478

11:14:37 PM

136

Primitive kangaroos have evolved

83846

0.970435

11:17:26 PM

100

Primitive cranes have evolved

84522

0.978261

11:28:42 PM

90

Modern sharks have evolved

84710

0.980435

11:31:50 PM

65

K-T Boundary--extinction of the dinosaurs and beginning of the reign of mammals

85179

0.98587

11:39:39 PM

60

Rats, mice, and squirrels have evolved

85273

0.986957

11:41:13 PM

60

Herons and storks have evolved

85273

0.986957

11:41:13 PM

55

Rabbits and hares have evolved

85367

0.988043

11:42:47 PM

50

Primitive monkeys have evolved

85461

0.98913

11:44:21 PM

28

Koalas have evolved

85874

0.993913

11:51:14 PM

20

Parrots and pigeons have evolved

86024

0.995652

11:53:44 PM

20-12

The chimpanzee and hominid lines evolve

86175

#

0.997391

11:56:15 PM

10.-4.

Ramapithecus exist

86212

#

0.997826

11:56:52 PM

4

Development of hominid bipedalism

86325

0.99913

11:58:45 PM

4.-1.

Australopithecus exist

86381

#

0.999783

11:59:41 PM

3.5

The Australopithecus Lucy walks the Earth

86334

0.999239

11:58:54 PM

2

Widespread use of stone tools

86362

0.999565

11:59:22 PM

2-0.01

Most recent ice age

86400

#

0.999998

12:00:00 AM

1.6-0.2

Homo erectus exist

86396

#

0.999957

11:59:56 PM

1-0.5

Homo erectus tames fire

86391

#

0.999891

11:59:51 PM

0.3

Geminga supernova explosion at a distance of roughly 60 pc--roughly as bright as the Moon

86394

0.999935

11:59:54 PM

0.2-0.03

Homo sapiens neanderthalensis exist

86399

#

0.999993

11:59:59 PM

0.05-0

Homo sapiens sapiens exist

86399

0.999989

11:59:59 PM

0.04-0.012

Homo sapiens sapiens enter Australia from southeastern Asia and North America from northeastern Asia

86400

#

0.999997

12:00:00 AM

0.025-0.01

Most recent glaciation--an ice sheet covers much of the northern United States

86400

#

0.999998

12:00:00 AM

0.02

Homo sapiens sapiens paint the Altamira Cave

86400

0.999996

12:00:00 AM

0.012

Homo sapiens sapiens have domesticated dogs in Kirkuk, Iraq

86400

0.999997

12:00:00 AM

0.01

First permanent Homo sapiens sapiens settlements

86400

0.999998

12:00:00 AM

0.01

Homo sapiens sapiens learn to use fire to cast copper and harden pottery

86400

0.999998

12:00:00 AM

0.006

Writing is developed in Sumeria

86400

0.999999

12:00:00 AM