well, that's an interesting point. especially considering the Great Flood.
consider this quote from Solcomhouse:
"Estimates of global species diversity have varied from 2 million to 100 million species, with a best estimate of somewhere near 10 million, and only 1.75 million known species of living organisms on earth have been identified."
do you think that Noah was able to collect and store in the ark at least 10 million species of animals (times 2 or times 7 depending on the species, if you follow me)? Its overall dimensions were at least 450 feet long, 75 feet wide and 45 feet high with three interior decks.
hm, actually doing some research on this, i found a page that pretty much makes my point invalid, saying that it was possible to do it, mainly since only about 35,000 animals would have been required to repopulate the earth's animal population. a lot of animals (sealife, insects, etc) could have survived outside the ark. it makes for an interesting read, and although it's on a "christian answers" website not run by the WTB&TS, it's pretty factual. http://www.christiananswers.net/q-eden/edn-c013.html