Question

Earth's Mass Extinction Events



Through analysis of the fossil record, scientists have determined that Earth has experienced at least five mass extinction events. The timeline describes these five events.



Extinction event 1 occurred 445 million years ago during the ordovician period. It was likely caused by an intense ice age and 60 to 70% of global species went extinct. Extinction event 2 occurred 375 to 360 million years ago during the devonian period. It was likely caused from oxygen depletion in the oceans and 75% of global species went extinct. Extinction event 3 occurred 252 million years ago during the permian period. It was likely caused from asteroid impacts and intense volcanic activity and 95% of the global species went extinct. Extinction event 4 occurred 200 million years ago during the triassic period. The cause is debated but likely from massive volcanic eruptions and asteroids and 70 to 80% of the global species went extinct. Extinction event 5 occurred 66 million years ago during the cretaceous period. It was likely caused from an asteroid impact and 75% of the global species went extinct.



The following question has two parts. First, answer Part A. Then, answer Part B.



Part A:

Scientists believe that an asteroid impact caused the Cretaceous extinction event 66 million years ago. An impact crater off the coast of Mexico's Yucatan Peninsula is evidence for this theory. The asteroid hit Earth at a high velocity, which destroyed the surrounding area and sent a large amount of materials into the atmosphere, blocking sunlight globally. Which BEST describes how the asteroid impact caused this extinction event?


The initial impact destroyed all the species on Earth.


The initial impact did not destroy any of the species on Earth.


The initial impact destroyed only the species in the surrounding areas.


The initial impact destroyed nearby species and more were destroyed after.





Part B:

Which supports the choice from Part A?


The initial impact changed Earth's environment, leading to global extinctions.


The initial impact produced enough energy to destroy all the species on Earth.


The initial impact was not powerful enough to destroy any of the species on Earth.


The initial impact only changed the immediate environment, affecting nearby species.

Answer 1

Part A:
The initial impact destroyed nearby species and more were destroyed after.

Part B:
The initial impact changed Earth's environment, leading to global extinctions.

Brief explanation: The impact obliterated life locally and lofted dust and aerosols into the atmosphere, blocking sunlight and disrupting climate and ecosystems worldwide, which caused widespread secondary extinctions.