Here are some of the facts which render the flood story impossible:
1.due to factors such as the speed of the water current, no trees could have survived the flood. yet, individual trees have been found that are 6,000 and even 10,000 years old, and a tree colony exists today which dates back over 80,000 years. noahs ark was 4000 years ago.
2. genetic variation can be measured in species thereby shedding light on their history. cheetahs, for example have so little variation that they are all essentially inbred. scientists estimate that the cheetah population dwindled to possibly as few as 500 approx. 10,000 years ago. almost all other living species show differentiation at such a higher level that their lineage can be traced to dates far earlier. humans through DNA can be traced to common parentage over 100,000 years ago. it is completely scientifically implausible that all living things achieved their measured levels of genetic differentiation from just TWO mates, a mere 4000 years ago.
3. neglecting the impossibility of fitting the millions of species on a single boat that could never have floated nor been designed nor built with available technology, engineering and tools, by a few men , in that short time.......
there was no time to collect the species. noah and family would have had to collect over 300,000 beetles. yup, just beetles. and they collected them from all over the world. and what about the 1,000,000 species of insects? again, from all over the world. sound likely?
4. many species can only survive in their climate. polar bears would not have survived the trip. neither would many species from warmer climates. not only did they make it to the ark, but noah must have had some wonderful refrigeration and heating set-up aboard the mighty ship.
5.was the water freshwater or saltwater?
if fresh, no saltwater fish would have survived to exist today. if saltwater, no freshwater fish today.
6.how did animals that cant fly or swim get from mt. ararat in asia to australia? there are many species which exist only there.
7.light doesnt penetrate the ocean more than about 500 ft. if the earth were submerged under 29,000 ft. in order to cover mt. everest, no marine plant life would have survived.
i'll stop here. there are many more.
and dont bother with the "miracle " defense since these are not areas ever mentioned as being miraculous. they were to be believed as within the natural order.
ah-pee-chorus also noted this:
…Extensive writings exist for the sumerian civilization which date from before 3000BCE (hundreds of years before the bible flood), straight through to a period many hundreds of years after. there was no mention of the flood, they were writing in sumerian before the bible story of babel claimed any other languages existed, and if all were killed in flood except noahs clan, it would have taken quite a while for those descendants to speak and be able to write the exact same language that had been spoken prior to the flood.