Geologic Time Chart
Use the prompts below to complete the geologic time chart then answer the accompanying questions.
1. Each time period is marked by a particular distinction. Describe what that defining characteristic is and use one example from above to
illustrate your point.
2. How do major geologic events affect biodiversity?
3. Assuming that it takes approximately 1,000 years to form 1” of top soil, how did geologic events affect the growth of plants in that time
period?
Era Designations
Age of Invertebrates
Age of Mammals
Age of Reptiles
Period and Epoch
Designations
Age of Ammonites
Age of Amphibians
Age of Ancient Life
Dinosaurs and mammals first appear
Explosion of invertebrate forms
First humanoids evolve, mega fauna
Age of Dinosaurs
Fish and fungus first appear
Age of Eurypterids (Sea
Scorpians)
Age of Fishes
Fish dominate, first amphibians and trees
appear
Formation of coal swamps and limestone
deposits
Human civilization dominates
Invertebrates dominate, first land plants
and insects appear
K-T extinction (75%), first flowering plants
Largest mass extinction, amphibians
dominate
Mammals dominate, modern birds appear
Reptiles dominate, first birds appear
Age of Graptolites
Age of Mammals
Age of Man
Age of Stomatolites
Age of Trilobites
Coal Age
Ice Age
The Rockless Eon
*mya = million years ago
Fossils
Geologic Events
Alps and Himalayas form, Columbia Plateau
Appalachian Mountains form, cool climate
Continents merge into a supercontinent,
Rodinia
Earliest Recorded life, biological evolution
begins
Formation of the Earth, chemical evolution
begins
Global shallow seas, warm climate
Great Lakes Form, Wiscon
Ice Age
Landmasses flat
Meteorite impacts Earth’s surface, Rocky
Mountains form
Oxygen builds up in the atmosphere
Pangaea breaks apart
Pangaea forms
Rodinia breaks apart, Burgess Shale forms
Shallow sea through North America
Southern glaciations, shallow North American
seas
EON
ERA
Cenozoic
“Age of Mammels”
Phanerozoic “Age of Visible Life”
Mesozoic
“Age of Reptiles”
Paleozoic
“Age of Invertebrates”
PERIOD
Quarternary (1.6 mya)
Tertiary (65 mya)
“Age of Mammels”
Cretaceous (145 mya)
“Age of Dinosaurs”
Jurassic (200 mya)
“Age of Reptiles”
Triassic (251 mya)
“Age of Ammonites”
Permian (300 mya)
“Age of Amphibians”
Carboniferous (355 mya)
“Coal Age”
Devonian (418 mya)
“Age of Fishes”
Silurian (441 mya)
“Age of Eurypterids”
Precambrian
EPOCH
Holocene (10,000 y)
“The Age of Man”
Pleistocene (1.6 mya)
“Ice Age”
Pennsylvanian
(314 mya)
Mississippian
(355 mya)
FOSSIL DOMINANCE
Human Civilization
Dominates
First humanoids evolve,
mega fauna
Mammals dominate,
modern birds appear
K-T extinction (75%)
First flowering plants
Reptiles dominate, first
birds appear
Dinosaurs and mammals
first appear
Largest mass extinction,
amphibians dominate
Formation of coal
swamps and limestone
deposits
Fish dominate, first
amphibians and trees
appear
Invertebrates dominate,
first land plants and
insects appear
First fish and fungus
appear
GEOLOGIC EVENT
Great Lakes Form, Wisconsin
Glaciation
Ice Age
Alps & Himalayas form,
Columbia Plateau
Meteorite impacts Earth’s
surface, Rocky Mountains
form
Pangea Breaks apart
Pangea Forms
Southern Glaciation, shallow
North American seas
Appalachian Mountains
form, cool climate
All land masses are generally
flat
Proterozoic (2500 mya)
Ordovician (490 mya)
“Age of Graptolites”
Cambrian (544 mya)
“Age of Trilobites”
“Age of Stromatolites”
Archeozoic (4000 mya)
“Age of Ancient Life”
Global shallow seas, warm
climate
Rhodinia breaks apart,
Burgess Shale forms
Continents merge into a supercontinent, Rhodinia,
Oxygen builds up in the atmosphere
Earliest recorded life, biological evolution begins
Hadean (4600 mya)
“The Rockless Eon”
Formation of the Earth, chemical evolution begins