GEOLOGICAL TIME SCALE



GEOLOGICAL TIME SCALE
TIME UNITS OF THE GEOLOGICAL TIME SCALE
DEVELOPMENT OF PLANTS AND ANIMAL
EON
ERA
PERIODS
EPOCH




QUARTERNARY
(0-50) mya
HOLOCENE
Mental age, supremacy of man
PLEISTOCENE (ice age)
Human appeared (homo sapience)






COENOZOIC

TERTIARY
(50-100) mya
PLIOENE
Ape like ancestors of human
MEIOCENE
Merychippus
OLIGOCENE
Anthropoid evolved from monkey rise of monocot
EOCENE
Eohippus appeard
PALAEOCENE
Origin of primates
MESOZOIC
CRETACEOUS
(100-150) mya

AGE OF
REPTILES
Dinosaur extinct, appearance of gymnosperm
JURASSIC
(150-200) mya
Origin of birds
Golden age of dinosaur
TRIASSIC
(200-250) mya
Origin of dinosaur & oviparous mammals






PALAEOZOIC
PERMIAN
(250-300) mya

Trilobites extinct
CARBONIFEROUS
(300-350) mya

Origin of reptile (syamauria)
Amphibian dominant
DEVONIAN

Orgin of amphibian
true fish dominant
SILURIAN

Origin of true fish
jawless fish dominant
ORDOVICIAN

Origin of chordata
Origin of jawless fish
Giant molluscs were dominant
CAMBRIAN

Origin of Trilobites






PROTEOZOIC


Origin of protozoa, sponges, coelentrata, annelida and Mollusca






ARCHAEOZOIC


Origin of prokaryotes and eukaryotes

AZOIC


Chemical evolution



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