other species may seem abundant, having no reason to

fear that their disappearance may be imminent. closer

examination may reveal that they are long overdrawn 

in the book of life, marked for extinction as surely as 

if they had been scythed down in their prime. while they 

may be abundant in the habitat to which they have become

accustomed, further removal of habitat—even if moderate—

may ensure their extirpation. they are, quite literally, 

living on borrowed time.

henry gee

a (very) short history of life on earth