History of the Life on Planet Water
Shown below are the key events with time expressed as billions of years before present, how long ago using
converting the time life has been on earth to one year, and a time and date over such a year.
Years Before Present How Long Ago Time & Date
(Not to scale) (converted to one year)
Present climate; modern humans;
modern mammals
40,000 ____________________________________________________________ 6 minutes 2354 hours 31 Dec
Recent ice ages; various human species;
mammoths
1,640,000 ____________________________________________________________ 4 hours 2000 hours 31 Dec
Near-human species, Australopethecines;
near modern mammals
5,200,000 ____________________________________________________________ 13 hours 1100 hours 31 Dec
Apes flourish; garsses and savanah
develop; grazing animals evolve
23,300,000 ___________________________________________________________ 2 days 10 hours 1400 hours 28 Dec
Monkeys, apes and other mammal
families evolve
35,400,000 ___________________________________________________________ 3 days 17 hours 0700 hours 27 Dec
Posimiams flourish; first monkeys
and precursors
56,500,000 ____________________________________________________________ 5 days 19 hours 0500 hours 25 Dec
Earliest primates (protoprosimians);
Mammals diversify
65,000,000 ____________________Extinction______________________________ 6 days 19 hours 0500 hours 24 Dec
Archaic mammals and birds begin to
replace dinosaurs; flowering plants
146,000,000 ______________________________________________________________ 15 days 16 Dec
Dinosaurs dominant; primitive mammals
spread; first toothed birds; squid;
frogs and salamanders
208,000,000 ______________________________________________________________ 22 days 09 Dec
Earliest primates (protoprosimians);
Mammals diversify
245,000,000 ____________________Extinction_________________________________ 25 days 06 Dec
Spread of reptiles and insects;
first mammal-like reptiles
290,000,000 ______________________________________________________________ 30 days 01 Dec
Amphibians dominaant; conifer florest flourish;
repiles and modern insects appear
363,000,000 ____________________Extinction_________________________________ 37 days 24 Nov
Fish dominant; amphibians appear
first forests
409,000,000 ______________________________________________________________ 43 days 18 Nov
First land plants; fish with jaws;
first air breathing animals on land
439,000,000 ____________________Extinction_________________________________ 45 days 16 Nov
Invertebrates dominant; first vertebrates
jawless fish
510,000,000 ____________________Extinction_________________________________ 53 days 08 Nov
Invertebrates dominant; worms,jellyfish
trilobites, etc.;
first plants ?
Ozone layer formed? ___
570,000,000 ____________________Extinction_________________________________ 59 days 02 Nov
Unicellular forms prominant; first
multicellular forms as invertebrates
Eukaryote explosion
High Oxygen level ____
800,000,000 ______________________________________________________________ 83 days 07 Oct
Aerobic eukaryotes with mitochondria and
chloroplasts as engulfed protocysts;
early land plants cause buildup of oxygen ?
1,500,000,000 ______________________________________________________________ 156 days 26 July
Unicellular forms prominant; ironoxide bands
in red beds show oxygen building up in
atmosphere
1,800,000,000 ______________________________________________________________ 187 days 24 June
Unicellular forms predominant; cyanobacteria
purple algae start producing oxygen
Oxygen appears _______
2,000,000,000 ______________________________________________________________ 208 days 03 June
Unicellular forms predominant;
algal mats in fossil record
2,700,000,000 ______________________________________________________________ 281 days 22 March
Unicellular forms predominant; first
eukaryotes (anaerobic forms without
mitochondria)
3,000,000,000 ______________________________________________________________ 321 days 20 Feb
First edidence of life;
prokaryotes
First Life ______________
3,400,000,000 ______________________________________________________________ 354 days 10 Jan
Simple carbon compounds found in
ancient rocks from this age
3,500,000,000 _________________________________________________
Permanent crust, oceans and atmosphere
formed, conditions now suitable for life
Suitable for Life ______
4,000,000,000 _________________________________________________
Planet Water formed as a planet
4,600,000,000 _________________________________________________
BIG BANG
15,000,000,000 _________________________________________________
