sections
definitions
....can happen because....
era characteristics 1
era characteristics 2
100
the geologic time scale divides all thoes years into________.
What is sections
100
________ is the death of every member of a species
What is extinction
100
extinction can happen because......
competetion between the species so some organisms ran out of food
100
4.6 billion-542 million years ago no 02 3.6 billion years ago (prokaryotes)
What is precambrain era
100
largest mass extinction mass extinction cause unknown 90% of ocean life and 78% land life died
What is permian extinction
200
the largest sections are called _____.
What is eons
200
_________ is the extinction of many species at the same time.
What is mass extinction
200
mass extinction can happen because.......
gradual changes in the climate or ocean currents
200
one celled and no nuclens cyanobacteria (first organism) formed 02 and 03 (ozone) 03 protects the earth and organisms could then live on land too!
What is prokaryote era
200
251 million years ago age of reptiles evoloved into other species
What is mesozoic era
300
eons are divided into _____.
What is eras
300
___________ is when gradual changes in the climate or ocean currents
What is uniformitarianism
300
mass extinction can also happen because.......
catastrophic events
300
2.6 billion years ago many celled and with a nucleus evolved into the organisms on earth today
What is eukaryote era
300
65 million years ago to today fossils are in the top layers land and climate has changed a lot
What is cenozoic era
400
eras are divided into ________.
What is periods
400
give an example of an catastrophic event
an asteroid hitting the Earth and blocking out sun rays
400
extinction can also happen because......
environment change and some organisms could not survive in the new environment
400
542-251 million years ago divided into 6 periods many new life forms/cambrain explosion organisms with hard shells giant ferns and salamanders
What is paleozoic era
400
mass extinction 65 million years ago all dinosaurs and half plants and animals went extinct sientists think asteroid hit and caused it
What is cretaceous-tertiary extinction
500
periods are divided into ______.
What is epics
500
the oldest sections are shown on the ________, and the recent sections would be on the _____.
What is bottom;top
500
give an example of a mass extinction
What is dinosaurs
500
65 million years ago to today fossils are in the top layers land and climate change a lot
What is cenozoic era
500
4.6 billion-542 million years ago 3.6 billion years ago (prokaryotes) no 02
What is precambrain era
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