Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/6

Click to flip

6 Cards in this Set

  • Front
  • Back
How many mass extinctions have there been in Earth's history, as far as we can tell by geological records?
Five.
Around the world, what event coincided with the disappearance of the "giant mammals"?
The arrival of humans in the territory of the giant mammals.
What factors have been attributed to the extinction of large mammals?
Human activity:
Hunting practices
Setting fire to the landscape to flush out prey
What is believed to be the main culprit in the recent widespread death of amphibians?
A fungus belonging to a group called chytrids
What was so remarkable about the chytrid?
Chytrids had never been known to attack vertebrates before, so an entirely new genus had to be created to house this new group of fungi.
What was the significance of the African clawed frog?
In the 1930's, Lancelot Hogben discovered that females of the species laid eggs when injected with certain human hormones. This became a way to test for pregnancy and these frogs were exported all over the world. They are thought to be one of the origins of the amphibian-killing chytrids.