sections
the geologic time scale divides all those years into________.
What is sections?
________ is the death of every member of a species
What is extinction?
Extinction can happen because......
What is competition between the species so some organisms ran out of food?
Our current time interval
What is the holocene epoch?
largest mass extinction mass extinction cause unknown 90% of ocean life and 78% land life died
What is permian extinction?
The largest sections are called _____.
What is eons?
_________ is the extinction of many species at the same time.
What is mass extinction?
Mass extinction can happen because.......
What gradual changes in the climate or ocean currents?
One celled and no nucleus cyanobacteria (first organism) formed 02 and 03 (ozone) 03 protects the earth and organisms could then live on land too!
What is archean eon?
251 million years ago age of reptiles evolved into other species
What is mesozoic era?
Eons are divided into _____.
What is eras?
This term means "middle"
What is meso?
Mass extinction can also happen because.......
What is catastrophic events?
2.6 billion years ago many celled and with a nucleus evolved into the organisms on earth today.
What is proterozoic era?
It is known as the "age of the amphibians".
What is paleozoic era
Eras are divided into ________.
What is periods?
Give an example of an catastrophic event
What is n asteroid hitting the Earth and blocking out sun rays?
Extinction can also happen because......
What is environment change and some organisms could not survive in the new environment?
542-251 million years ago divided into 6 periods many new life forms/cambrian explosion organisms with hard shells giant ferns and salamanders
What is paleozoic era?
mass extinction 65 million years ago all dinosaurs and half plants and animals went extinct scientists think asteroid hit and caused it
What is cretaceous-tertiary extinction?
Periods are divided into ______.
What is epochs?
The oldest sections are shown on the ________, and the recent sections would be on the _____.
What is bottom;top?
Give an example of a mass extinction
What is an ice age?
65 million years ago to today fossils are in the top layers land and climate change a lot
What is cenozoic era?
4.6 billion-542 million years ago 3.6 billion years ago (prokaryotes) no 02
What is precambrian era