You talk out of both sides of your mouth. For purposes of defending the ark myth, you're all about evolution generating diversity, although you won't use the word. Differentiate is your word.
Then, in the same post where you talk about the tree of life generating all kinds of new branches since Noah's day, you describe a planet that has been degenerating at an accelerating since it was made. Everything you see in nature cries degeneration to you despite growth everywhere. Yes, living things eventually die and decompose, but you seem to have missed the phase where they grew and developed first both individually and as populations across generations.
This is what happens when your belief set is a patchwork of things people just made up. It's internally self-contradictory and it contradicts the evidence.
Believers have to contend with that in multiple areas of study, such as biblical prophecy. If these prophecies came from some prescient source able to see the future, then you wouldn't have to invent all kinds of just-so apologetics to explain it away. Likewise with the contradictions between the Gospels. Likewise with the perfect god that regretted its creation, and which allows gratuitous suffering. Likewise with the god that sees the future perfectly but allows free will. Everywhere, we see evidence of human creativity rather than accurate reporting, and mistakes made in the inventing as various writers tell varying tales that often are impossible or contradict one another.
The believer has to spin multiple intricate explanations to try to reconcile all of this and maintain the illusion that is what it claims to be - of divine provenance, and therefore true and accurate - but the unbeliever has a single, simple explanation that explains it all. That fact alone tells you that the supernaturalistic explanation is likely wrong and the other correct.
An interesting example of that from history involves early explanations for what is called retrograde motion in the planets. Ptolemy's proposed epicycles for explaining the retrograde motion of Mars in his erroneous geocentric model, where from earth, Mars appears to move in one direction, reverse direction for a while, and then reverse again (see dotted blue line below). So, he proposed so-called epicycles (shown in solid blue) to account for that.
But this ad hoc and incorrect invention added considerable complexity to his model. To keep the earth in the center and the other planets orbiting about it, he added these phantom movements that had planets orbiting around nothing and the earth simultaneously:
But put the sun in the center as Copernicus did and watch what happens. The paths of the planets are greatly simplified. A simpler mathematical treatment is always a preferred one according to Occam's parsimony principle, and if no new evidence surfaces that requires this extra complexity to account for, the simpler narrative is likelier to be correct as was the case with apparent retrograde planetary motion. Look at how much simpler and consistent with reality the heliocentric model is, where everything is orbiting the sun rather than the earth and nothing needs to be orbiting around empty space:
All of the problems with the flood story are easily explained once we recognize it for what it is - something humanity invented.