"If the forest continues to disappear at its present pace, the koala will approach extinction," said the biologist.
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pajbermanSeptember 4, 2019
confused on how B and diagram of biologist
I am still confused on how you made the jump from how B is consistent with the biologist's claim? It seems to me that B says Deforestation stopped => koala is extinct whereas the biologist says forest continues to disappear => koala extinct. if you do the contrapositive you get if koala not extinct, the forest does not continue to appear.
but B says that the koala DOES become extinct.
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This is a good question with which to practice our sufficient and necessary conditions.
Biologist: If the forest continues to disappear (DEF), the koala will approach extinction (KE).
DEF - - - - - - - - - > KE (suf) (nec)
We can only gather one thing from the biologists statement: If we lose the forests, the koalas die. However, losing the forests may be only one of many factors needed to save the koalas. It remains possible that deforestation is stopped, yet the koalas could go extinct from another reason. Here is the contrapositive of the biologist's statement:
not KE (koalas survive) - - - - - - - -> not DEF (deforestation stopped) (suf) (nec)
This does not conflict with answer choice B. Stopping deforestation does not guarantee the survival of the koalas. They could be killed by a koala disease, or wiped out by predators. Fulfilling the necessary condition does not guarantee the sufficient condition, but eliminating the necessary condition eliminates the sufficient condition.
Do you see why this is different from the statement of the politician?
The politician flips the sufficient and necessary conditions.
not DEF - - - - - - -> not KE
According to him/her, saving the forests does guarantee koala survival. This is why the politician's statement conflicts with B, but the biologist's doesn't.
