The Evolutionary Epic: Crash Course Big History #5

What did Charles Darwin observe about finches on the Galapagos Islands?

• Their beaks were all the same size.

• Their beaks were adapted to different food sources.

• They only ate one type of food.

• They had no beaks at all.

In science, what does the word "theory" mean?

• A wild guess.

• An idea that has not been tested.

• Something that has been tested many times and explains many observations.

• A personal opinion.

Which of these is NOT a type of evidence that supports the theory of evolution?

• Fossil evidence.

• DNA sequencing.

• Radiometric dating.

• Stories from ancient myths.

What happens when a mass extinction event clears out many niches?

• Evolution slows down.

• Surviving species evolve new traits very quickly.

• All life on Earth disappears.

• Only plants survive.

What bug-like creatures with exoskeletons first appeared in the Cambrian period?

• Trilobites

• Anomalocaris

• Scorpions

• Dinosaurs

What two major climate changes caused the Ordovician extinction event?

• A long drought and then heavy floods

• A major freezing period and then a radical heating period

• Many volcanic eruptions and then an asteroid impact

• A sudden rise in sea levels and then a drop in oxygen

During the Silurian period, what happened to the amount of oxygen in the atmosphere?

• It decreased to 10%

• It stayed the same

• It increased to between 30% and 35%

• It became too low for life to survive

Which extinction event is known as "The Great Dying" and was the largest in the past half-billion years?

• The Ordovician extinction

• The Devonian extinction

• The Permian extinction

• The Triassic extinction