Chapter 10 – Geologic Time

division of Earth's history into time units based largely on the types of life-forms that lived only during certain periods

Help scientists divide Earth's history into time units. the oldest rocks on the earth contain only a few fossils.

longest and major divisions in geologic time They are divided into subdivisions called Eras

are divided into subdivisions called Periods.

are divided into smaller units called Epochs.

Is the earliest and longest era in the geologic time scale During this era earliest life forms appeared.

1st appeared in the Precambiran time

Is a Cyanobacteria thought to be one of the earliest life forms on Earth, which gave oxygen

followed the Precambrian; Ferns, fish, amphibians and reptiles appeared in the Paleozoic aea

a single large landmass that was composed of all Earths continents joined together. Formed during the Paleozoic era.

followed the Paleozoic Era. Dinosaaurs, birds, small mammals and flowering plants first appeared during Mesozoic time.

Evolved from dinosaurs

the most recent era and it marks the appearance of humans and large mammals

A group of organisms that reproduce only with members of their group.

the process by which individuals adapt well to their environment survive and reproduce.

change of organisms over geologic time

Cyanobacteria, Jelly fish, Fish, amphibians, reptiles, birds, mammals

an organism that lived hundreds of millions of years ago with bodies divided into three sections.

Precambrian Era : Cyanobacteria

Paleozoic Era: Reptiles

Mesozoic Era : Dinosaurs

Cenozoic Era: Humans