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How is the ‘sixth episode of extinction’...

How is the ‘sixth episode of extinction’ of species on earth, now currently in progress, different from the five earlier episodes?. What is it due to? Explain the various causes that have brought about this difference.

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Sixth episode of extinction is due to the climatic changes that killed them. Five episode that extinct today are
i. early reptiles ii. pelycosaurs iii. thecodonts
iv. therapsids v. dinosaurs
The sixth episode contains turtles, lizards, snakes, tuataras, crocodile, birds and mammals.
Some are facing danger and are very near to extinct. e.g. the population of white Bengal tiger is decreasing rapidly due to unlimited hunting to make money.
The land reptiles i.e., dinosaurs, suddenly disappeared from the earth (mass extinction) about 65 million years ago due to the changes in climate, while the small sized reptiles continue to exist even today.
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