-------------------------------------------- EVOLUTIONARY/GEOLOGICAL TIMELINE
VERSION 1.0 --------------------------------------------

 This is a copy of an evolutionary/geological timeline that I have

 been making.

 I would be grateful for factual, spelling, and grammar

 corrections. I would be grateful for suggestions as to how to

 better word specific entries so as to make them clearer. I am

 also keen to add interesting events to the timeline and would

 appreciate suggestions.

 Please send any suggestions to me via email.

 Niel Brandt


 This document is copyright Niel Brandt 1994. You are allowed to copy,

 distribute, and edit this document at will without any obligation as long

 as you do not remove the above header. Reproduction and distribution for

 personal profit is not permitted.



Time (Myr ago)  Event


4600            Formation of the approximately homogeneous solid Earth by

                planetesimal accretion 

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 

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 

4000            Bombardment of the Earth by planetesimals stops 

3800            The Earth's crust solidifies---formation of the oldest rocks

                found on Earth 

3800            Condensation of atmospheric water into oceans 

3500--2800      Prokaryotic cell organisms develop 

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

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


2000            The Oklo natural fission reactor in Gabon goes into operation 

1600            The last reserves of reduced iron are used up by the

                increasing atmospheric oxygen---last banded iron formations 

1500            Eukaryotic cell organisms develop 

1500--600       Rise of multicellular organisms 

580--545        Fossils of Ediacaran organisms are made 

545             Cambrian explosion of hard-bodied organisms 

528--526        Fossilization of the Chengjiang site 

517--515        Fossilization of the Burgess Shale 

500--450        Rise of the fish---first vertebrates 

430             Waxy coated algae begin to live on land 

420             Millipedes have evolved---first land animals 

375             The Appalachian mountains are formed via a plate tectonic

                collision between North America, Africa, and Europe 

375             Appearance of primitive sharks 

350--300        Rise of the amphibians 

350             Primitive insects have evolved 

350             Primitive ferns evolve---first plants with roots 

300--200        Rise of the reptiles 

300             Winged insects have evolved 

280             Beetles and weevils have evolved 

250             Permian period mass extinction

230             Roaches and termites have evolved 

225             Modern ferns have evolved 

225             Bees have evolved 

200             Pangaea starts to break apart 

200             Primitive crocodiles have evolved 

200             Appearance of mammals 

145             Archaeopteryx walks the Earth 

136             Primitive kangaroos have evolved 

100             Primitive cranes have evolved 

90              Modern sharks have evolved 

65              K-T Boundary---extinction of the dinosaurs and beginning of

                the reign of mammals 

60              Rats, mice, and squirrels have evolved 

60              Herons and storks have evolved 

55              Rabbits and hares have evolved 

50              Primitive monkeys have evolved 

28              Koalas have evolved 

20              Parrots and pigeons have evolved 

20--12          The chimpanzee and hominid lines evolve

10--4           Ramapithecus exist

4               Development of hominid bipedalism

4--1            Australopithecus exist

3.5             The Australopithecus Lucy walks the Earth

2               Widespread use of stone tools

2--0.01         Most recent ice age

1.6--0.2        Homo erectus exist

1--0.5          Homo erectus tames fire

0.3             Geminga supernova explosion at a distance of

                roughly 60 pc---roughly as bright as the Moon

0.2--0.03       Homo sapiens neanderthalensis exist

0.05--0         Homo sapiens sapiens exist

0.04--0.012     Homo sapiens sapiens enter Australia from southeastern Asia

                and North America from northeastern Asia

0.025--0.01     Most recent glaciation---an ice sheet covers much of the

                northern United States

0.02            Homo sapiens sapiens paint the Altamira Cave

0.012           Homo sapiens sapiens have domesticated dogs in Kirkuk, Iraq

0.01            First permanent homo sapiens sapiens settlements

0.01            Homo sapiens sapiens learn to use fire to cast copper and

                harden pottery

0.006           Writing is developed in Sumeria

Time (Myr ago)  Event

5000--1500      Archeozoic (Archean) era

1500--545       Proterozoic era

                Paleozoic era ``Ancient life''

545--505           Cambrian period

505--438           Ordovician period

438--410           Silurian period

410--355           Devonian period

355--290           Carboniferous (Mississippian/Pennsylvanian) period

290--250           Permian period

                Mesozoic era ``Middle Life''

250--205           Triassic period

205--135           Jurassic period

135--65            Cretaceous period

                Cenozoic era ``Recent Life''

                   Tertiary (Paleogene/Neocene) period

65--55                Paleocene epoch

55--38                Eocene epoch

38--26                Oligocene epoch

26--6                 Miocene epoch

6--1.8                Pliocene epoch

                   Quaternary period

1.8--0.01             Pleistocene epoch

0.50--0.25                Lower Paleolithic

0.25--0.06                Middle Paleolithic

0.06--0.01                Upper Paleolithic

0.01--0               Holocene epoch