Over the last thousand years, plant species native to islands have gone extinct at a much faster rate than have those...

Kenji on June 10, 2020

December 2017 SEC 3 Q8

So, is the biologist claiming that island plants are going extinct at much faster rate because they are not adapted to large land mammals? And if land mammals were to be introduced to the island plant population it will increase the rate of extinction? Is my understand of the passage correct? How would it increase the rate?

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Shunhe on June 14, 2020

Hi @kenken,

Thanks for the question! Yes, that is the claim being made by the biologists, that plant species native to islands have been going extinct at a much faster rate than mainland plants because they haven’t adapted defenses against being eaten by large land mammals that the mainland plants already have. And if humans colonize a place, then populations of large land mammals are established on islands, which will increase the rate of extinction, presumably from the large land mammals eating the plants, which are relatively defenseless against them.

Hope this helps! Feel free to ask any other questions that you might have.

Kenji on June 16, 2020

Thanks for the clarification. I don't quite understand why answer D is correct. Isn't the island plants already going extinct at much faster rate? How would colonizing the island increase the rate? Thanks again!

on July 21, 2021

It supports the idea that land mammals are eating the defenseless plants on the island