Busy. Please wait.
Log in with Clever

show password
Forgot Password?

Don't have an account?  Sign up 
Sign up using Clever

Username is available taken
show password

Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
Your email address is only used to allow you to reset your password. See our Privacy Policy and Terms of Service.

Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
Didn't know it?
click below
Knew it?
click below
Don't Know
Remaining cards (0)
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Dnsr Notes 25

Aliens, Asteroids, and Volcanoes

What percentage of dinosaurs are now extinct? 99.9%
How long did dinosaurs thrive for? 150 my
How many species of dinosaurs exist today? 10,000
How does background extinction compare to mass extinction? Background extinction continually occur and are isolated extinctions. Mass extinctions occur great and small but are still substantial events.
What are the five mass extinctions? End-ordovician, late devonian, end-permian, end-triassic, end-cretaceous
When was the end-Ordovician? (445 Mya)
Late Devonian? (374 mya)
end-permian and what percentage went extinct? (252.5 mya) 80%
end-triassic (201.5 mya)
end-cretaceous (65.5 mya)
What was the K-T extinction? Cretaceous-tertiary
What are the three main hypoth
Created by: Chelseagirl2508
Popular History sets




Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!
"Know" box contains:
Time elapsed:
restart all cards