The History of Life
Science

A rapid increase in the diversity of lifeforms that occurred during the Paleozoic era
Cambrian explosion
A rapid increase in the diversity of lifeforms that occurred during the Paleozoic era. Cambrian explosion. The Cambrian explosion was a period around 541 million years ago when there was a sudden increase in different types of animals on Earth.

States that mitochondria and chloroplasts evolved from eukaryotic cells that entered prokaryotic cells
Endosymbiotic theory
States that mitochondria and chloroplasts evolved from eukaryotic cells that entered prokaryotic cells. Endosymbiotic theory. This theory suggests that some organelles in eukaryotic cells originated from ancient symbiotic relationships where one cell lived inside another.

A timeline of Earth's history based on major changes
Geologic time scale
A timeline of Earth's history based on major changes. Geologic time scale. The geologic time scale is a system used by scientists to organize Earth's history into different periods based on significant geological and biological events.

A fossil from an organism that existed for a short time, it is used to determine the age of other fossils
Index fossil
A fossil from an organism that existed for a short time, it is used to determine the age of other fossils. Index fossil. An index fossil helps scientists figure out how old other rocks or fossils are because it comes from a species that lived for a short, specific time period.

A unit of geologic time that lasts tens of millions of years, it is longer than an epoch but shorter than an era
Period
A unit of geologic time that lasts tens of millions of years, it is longer than an epoch but shorter than an era. Periods are segments of time in Earth's history used by scientists to organize geologic events.

The theory that Earth's crust is made of moving plates
Plate tectonics
The theory that Earth's crust is made of moving plates plate tectonics. Plate tectonics is the scientific idea that the Earth's surface is divided into large pieces that slowly move and interact, causing earthquakes and forming mountains.

Mammals with features like opposable thumbs, forward looking eyes, and a large brain, like humans, monkeys or apes
Primate
Mammals with features like opposable thumbs, forward-looking eyes, and a large brain, like humans, monkeys, or apes. Primate. A primate is a type of mammal that typically has these traits, allowing them to live in complex environments.

Comparing the amount of radioactive and nonradioactive isotopes to determine rock age
Radiometric dating
Comparing the amount of radioactive and nonradioactive isotopes to determine rock age. Radiometric dating. It's a scientific method used to date materials like rocks by measuring the decay of radioactive isotopes within them.