16.5–16.6
16.5–Extinction reduces biodiversity.
An extinction occurs when all individuals in a species have died.
Q
A habitat with _______ disturbance is expected to have the greatest species richness.
- a) a great deal of
- b) an intermediate amount of
- c) predictable
- d) very little
- e) sporadic
What bird, once the most abundant in North America, was hunted to extinction by shooting and trapping during the 1800s?
- a) California condor
- b) blue-
footed booby - c) dodo
- d) passenger pigeon
- e) great auk
How many species do biologists estimate to be currently existing on earth?
- a) fewer than 1 million
- b) between 3 million and 5 million
- c) more than 1 billion
- d) between 5 million and 100 million
- e) between 1 million and 2 million
Which of the following is currently the leading cause of extinction?
- a) pollution
- b) habitat loss
- c) disease
- d) exotic species
- e) overexploitation
Currently, the major threat to most large land mammals is:
- a) invasive species.
- b) loss of genetic variation.
- c) overexploitation.
- d) habitat loss.
- e) mutation.
684