Mass Extinction Events
Dinosaurs roamed Earth for 135 million years. Then, after an asteroid struck Earth, dinosaurs and many other organisms became extinct. An event, such as a large asteroid striking Earth, can cause widespread extinction in plants and animals. Scientists call these mass extinction events. Throughout the history of life on Earth, there have been five mass extinction events.
The diagram shows the periods and the impact of 5 mass extinction events. From left to right, the periods in Millions of Years Ago are Cambrian from 540 to 490, Ordovician from 490 to 445, Silurian from 445 to 415, Devonian from 415 to 360, Carboniferous from 360 to 300, Permian from 300 to 250, Triassic from 250 to 200, Jurassic from 200 to 145, Cretaceous from 145 to 65, Tertiary from 65 to 1.8, and Quaternary from 1.8 to 0. The number of living families is shown as trapezoids next to each other, and the broader end marks a mass extinction event. The first mass extinction event was at the end of the Ordovician Period, 445 million years ago, and 50% of animal families, including many trilobites, became extinct. The second mass extinction event was at the end of the Devonian Period, 360 million years ago, and 30% of animal families, including many marine species and insects, became extinct. The third mass extinction event was at the end of the Permian Period, 250 million years ago, and 60% of animal families, including many marine species, insects, amphibians, and all remaining trilobites, became extinct. The fourth mass extinction was at the end of the Triassic Period, 200 million years ago, and 35% of animal families, including many reptiles, became extinct. The fifth mass extinction event was at the end of the Cretaceous Period, 65 million years ago, and 50% of animal families, including the last dinosaurs and many marine species, became extinct.
Multiple Select Question
Which TWO statements about mass extinctions are supported by the data?
A.
Trilobites could be found on Earth 350,000,000 years ago.
B.
Marine species became extinct on Earth over 350,000,000 years ago.
C.
Reptiles could be found on Earth over 200,000,000 years ago.
D.
Dinosaurs were on Earth for 540,000,000 years.
E.
Insects appeared on Earth 250,000,000 years ago.
1 answer
The two statements about mass extinctions supported by the data are:
B. Marine species became extinct on Earth over 350,000,000 years ago. (This is supported by the second mass extinction at the end of the Devonian Period, which occurred 360 million years ago, where many marine species became extinct.)
C. Reptiles could be found on Earth over 200,000,000 years ago. (This is supported by the fact that reptiles existed before the end of the Triassic Period, which was 200 million years ago, during which 35% of animal families, including many reptiles, became extinct.)
