What of the plants? How did they survive months of inundation? And if they all died, but regenerated from seeds after the water receded, how did Noah's boatload of animals get by in the time it would take for that to happen? What, for example, of those animals which depend on tree fruits and tree nuts, products of trees at least several years old?
How did bees survive, in the absence of flowering plants?
And how does this story account for those living plants which have been alive since before the date ascribed to this Great Flood? Or those clonal colonies which have been alive since before the Flood without setting seeds?
Reasonable questions I would think.
Thanks. There are more too. Where, for example, did all the extra water come from? Enough to cover the world including the mountains. And where did it go to afterwards?
And this water, was it fresh or salty?
And how did water-living plants and animals survive, given that many are very sensitive to changes in salinity, temperature and light levels? How did the marine food web survive, when sudden change of depth and salinity and turbidity would have wiped out the seagrasses, algae and other life forms down at the bottom?
How do you account for coral reefs, some many thousands of years old, which can only survive across quite a narrow set of criteria, specifically including depth, clarity and temperature?
And the olive leaf the bird brought back. How could that have been found? Olive trees submerged for a year won't survive - even growing them in poorly-drained soil will soon kill them.
What would you feed your obligate carnivore animals on for a year on the Ark?
The water was already here. The earth is
sort of a closed system. Where did the water go? If the land is smoothed out the water would be about two miles deep all over the world. A better question is, where did all the dry land come from?
Ninety percent of fossils are marine fossils. We have no idea what the pre-flood ocean was; whether salty or totally fresh. The world has places like Bonneville Salt Flats where the salt is hundreds if not thousands of feet deep. These places are call juvenile salt flows, or something like that. Even if the original ocean was fresh it would have become salty during the Flood when the bosoms of the deep opened up. Water, lava, salt and no telling what all else came forward.
The other questions you are considering are not accepting the idea we have no idea about plants and animals 4,500 years ago. Lots of scientific information has be overturned in the last half century.
The Bible tells us everything alive was vegetarian prior to the Flood. After it Noah was told, "Everything alive is for food." Obviously lots of things changed at that time.
That only addresses a couple of issues, and even then doesn't really answer. Taking it from the top, if the earth was completely "smoothed out" and all sources of water (including that currently trapped in rocks, as ice, and as water vapour) was available to cover it, the depth would be about 2700 m - rather less than 2 miles. That would be nowhere near covering Ararat (nearly 4000 m), let alone covering all the high mountains under the heavens ...to a depth of more than 15 cubits (Genesis 7:19-20), And of course the earth is not smoothed, nor was it smoothed during the Great Flood - the references to mountains confirm that.
As for whether the original ocean was salty or fresh, the thing is that there are forms of marine life that can only live in the one, or the other due (among other things) to the problem of osmoregulation. If all life was created in the first six days, these differences would have had to exist pre-Flood. If the sea was fresh water, those life forms adapted for life in the salt would not survive. Conversely those adapted for freshwater streams would not survive in the salt. There are comparatively few which can go from one to the other. If the Flood then comes along, clearly you replace a situation where there are rivers and springs of fresh water and seas of salt with floodwater of intermediate salinity (and high turbidity too), in which many species just could not have survived. Your alternative scenario, that the seas were fresh and then became salty with the Great Flood is equally problematic, because such a situation would kill all those life forms not adapted to that huge change in osmotic pressure.
There also those species which are littoral, depending on tides to wash in and then expose them over the course of each day, they all die too under 15 cubits of water over the highest mountain.
The salt at Bonneville Salt Flats is not "hundreds if not thousands of feet deep". It is up to 5 feet deep, in the deepest part, and tapers away to about an inch deep around the edges.
You say "we have no idea about plants and animals 4500 years ago". But in fact we do, both if you accept current science and if you insist on the literal truth of Genesis. Science tells us about plants and animals which existed 4500 years ago in a number of ways, including the fact that there are samples of them which have been found, including plant material, bones etc., there is DNA, there's cave art and even the fact that there are some living life forms which are actually more than 4500 years old. If instead we accept the literal truth of Genesis, all plants and animals alive now were made by the Creator in the first six days. They weren't replaced with different ones post-Flood, and so the olive tree of Genesis is the same olive tree now.
"The Bible tells us everything alive was vegetarian prior to the Flood." Well, it actually tells us that Abel kept flocks, and brought fat portions to offer the Lord. Jabal and his descendants also kept flocks. Putting that to one side, there are animals which in fact cannot survive on a vegetarian diet. They are obligate carnivores - cannot survive without meat. They don't have the specialised adaptations required for a vegetarian diet. As well as teeth adapted only for gripping and tearing meat, or crushing bones, or venom, or muscles to constrict prey, their digestive system simply cannot process vegetable matter. The changes necessary for them to go from a vegetarian diet to a meat diet would be quite major changes to their body.
