I don't find it reasonable that a scientist can tell us what things were like a billion years ago, or for that matter even 350 million years ago, with any degree of certainty.
You need to understand what the actual process is. The scientist asks herself questions such as, "What was Earth's atmosphere like 4 bn years ago? How hot was it? How much water was there?" She and her associates go looking for information, especially from geology, checking to see if James Webb can offer any possibilities from observing star formation, whether the Martian surveys might have anything relevant to think about, what the tectonic experts might be able to add ─ and so on. What lines of enquiry are suggested, what are ruled out, what are other scientists saying?
The team may not reach an important conclusion, in which case they may write up what they've been able to rule out and why.
Or they may find that a particular thesis supported by the evidence points in a particular direction ─ in which case they write that up as well.
What you read in the science press ─ which I trust you follow ─ will be only highlights, the conclusions reached and the alternatives ruled out. It's a summary of what our best-informed understanding of early times on earth presently is.
Science proceeds by empiricism and induction. It doesn't produce absolute statements, but it can verify from the evidence the statements it makes. Stories in books, including ancient books like the bible, don't have any such basis. Many of them are folktales, and read accordingly ─ Moses and Aaron's contest with Pharoah's magicians is a nice clear example, as is the Exodus, And you doubtless know that no archaelogical evidence supports the Egyptian Captivity reported in the bible.
And so on. The authors of the bible were up to date with the cosmology of their day, so they thought the earth was flat, and immovably fixed at the center of things and the sun stars and moon all went round it. (I can't recall whether I mentioned
>these< to you before or not, but they're worth your consideration.)
What laid the first dinosaur egg?
The way you've phrased that, clearly not a dinosaur ─ but (if we imagine we have a suitably specific and detailed definition of "dinosaur") equally clearly a veryverynearlydinosaur.
I see no reasonable evidence that natural selection would make sight or hearing or taste start developing to begin with. To me natural selection would be unable to even recognize a minuscule change toward say hearing for example.
You seem to think natural selection is purposeful. No, it's not. It works because it proceeds by a simple test of success or failure ─ did this critter live long enough to pass its genes on to another generation? If yes, that may be luck, or it may be that those particular genes produced one particular kind of advantage to surviving long enough to breed. And if the latter, then that advantage may be decisive and become characteristic of that particular species ("species" loosely defined here, since we're talking about changes to a species). Not only is evolution quite a simple idea but it works.