Page 158 - Grasp English B2 (Student Book)

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Science Extinction of Dinosaurs

There are two main schools of thought on why dinosaurs
became extinct approximately 66 million years ago. The A. Discuss with a partner.
event is thought to have claimed over three-quarters of 1. Why do you think dinosaurs became extinct?
all life on the planet at that time, including plant life. 2. What evidence of dinosaurs having existed

On the one hand, scientists believe this mass extinction can we see today?
may have been caused by a meteor, a theory put
forward by Luis and Walter Alvarez. Being the size
of a mountain, this meteor would have caused the
atmosphere of the Earth to fill with dust and debris on
impact, which would have had a catastrophic impact
on the climate. This theory is supported by the existence meteor – a piece of rock travelling through
of the Chicxulub crater, a 93-mile wide crater in Mexico. space
The second theory is that a huge volcanic explosion theory – a scientific idea
is likely to have had a similar effect on the Earth’s debris – rubbish remaining after something
atmosphere. Scientists have evidence of lava in India is destroyed
which is up to 6,000 feet deep in places. Given the catastrophic, drastic – terrible, extremely
Earth’s frequent volcanic activity, they argue that it is negative
more plausible that a volcano is the culprit of the mass
extinction than a meteor. crater – the hole left after something hits the
Earth
Whatever the cause, evidence suggests that drastic lava – liquid rock which comes from a volcano
climate change played a role in the dinosaurs dying out
– which is important given today’s climate emergency. plausible – likely, believable

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