Geologic Time
What are the four units of geologic time from largest to smallest?
Eons, Eras, Periods, Epochs
What is a mass extinction?
The extinction of many species within a short period of time
What is a land bridge?
A connection between two continents that were previously separated
What type of animals dominated the oceans during the Cambrian Explosion?
Invertebrates
What organism had lungs and could breathe air and was one of the earliest amphibians?
Tiktaalik
What is the largest unit of geologic time?
Eon
What can happen to a species if its environment changes and it cannot adapt?
It can become extinct
What can organisms do when they move across a land bridge and encounter a new environment?
They adapt and evolve to their new environments
During the Early Paleozoic, where did all life live?
In the oceans
What animals were the first to reproduce without requiring water?
Reptiles
What unit comes after an Era?
Period
What is evolution?
The change in species over time as they adapt to their environments
What is geographic isolation?
The separation of a population from the rest of its species because of a physical barrier
What imaginary line ran through what is now North America during the Early Paleozoic?
The Equator
What type of environment allowed plant material to eventually become coal?
Coal swamps
What unit comes after a Period?
Epoch
What are two things that scientists hypothesize may have contributed to the extinction of the dinosaurs?
Volcanism and a meteorite impact
Name one physical barrier that can cause geographic isolation.
A mountain range or an ocean
Why is the Middle Paleozoic sometimes called the Age of Fishes?
Because many types of fish lived during this time
What percentage of marine life-forms became extinct during the largest extinction in Earth's history?
95%
What do scientists study to help determine the order of Earth's history?
Rock layers and fossils
What evidence found in clay and rocks around the world supports the idea of a meteorite impact?
Iridium in clay and rocks
How can geographic isolation cause populations of the same species to change differently over time?
Separated populations can evolve differently as they adapt to different environments
What major geological feature was created when continents collided during the Middle Paleozoic?
Mountain ranges
When did the largest extinction in Earth's history occur?
At the end of the Paleozoic Era