Ozone depletion may have sparked prehistoric extinction event: study

A study published in Science Advances suggests that UV ray exposure 358 million years ago may have triggered a mass extinction of ancient fish and plants. Researchers analyzed a 6-meter-long mudstone core from Greenland, finding fossilized spores that transitioned from healthy to malformed, indicating DNA damage from UV-B rays. This event marked the second mass extinction in the Devonian period, leading to the disappearance of many species, including giant armored sharks. The extinction also wiped out early land-venturing fish, paving the way for five-toed tetrapods to become the precursors of modern land animals.

What event is suggested to have caused a mass die-off of ancient fish and plants 358 million years ago?

• Volcanic eruptions

• Ice age

• Ultraviolet ray exposure

• Meteor impact

What did the research team use to study the ancient spores?

• A 6-meter-long mudstone core

• A fossilized tree trunk

• A preserved amber sample

• A volcanic rock sample

What transition did the fossilized spores show?

• From healthy to malformed and blackened spores

• From aquatic to terrestrial spores

• From green to brown spores

• From small to large spores

What was a significant consequence of the second wave of extinction?

• The appearance of flowering plants

• The rise of dinosaurs

• The extinction of the first four-limbed fish

• The formation of the first oceans

Which group became the precursors of land animals after the extinction event?

• Four-toed tetrapods

• Six-toed tetrapods

• Three-toed tetrapods

• Five-toed tetrapods