And one other thought for
@FutureAndAHope
I think it's also important to understand how the Earth is layered and how we understand the fossil succession.
I shared a diagram above that looked like this:
But if we look more specifically at the earth, it might look something more like this:
And, this is just a cross section taken of the state of Wyoming. There's nothing particularly special about this location, it's just a map I pulled off of Google.
But, what's important is that, layers that are deeper are older than layers that are shallower. And this logically must be true, just as a paper on the bottom of a stack of papers on a desk must have been laid down prior to papers on top of a stack. The lower layers must rest at the bottom first. And this is just kind of a basic philosophical truth of reality, and there's not much to explain but hopefully it makes sense to everyone who reads it.
And so fossils in lower layers are considered to be older, or were laid down earlier in Earth history than fossils of shallower layers that were laid down at later points of time in Earth history.
And really at the heart of it, all we do is see what fossils are in each layer and just put them in order.
I think some young earth Creationists try to make it out to be some complex topic to confuse people, but it really isn't when you get down to the bread and butter of what the fossil succession really is.
Some deniers will say that fossils are used to date rocks and that rocks are used to date fossils and that it's circular and makes no sense. But in truth, the fossil succession really just comes down to the concept of superposition and understanding that lower layers of rock are older than shallower layers. This basic logical concept is really at the heart of all of geology and paleontology. And there really isn't much deniers can do about this.
Sometimes deniers will say, "well earthquakes can twist rocks around and out of order".
And while this is true, it should also be understood that rocks that have been twisted and broken and folded and flipped by earthquakes and other tectonic activity are readily observable and identifiable. Just like if someone took a shovel and started twisting and breaking and folding and flipping and smashing someone's flower bed in their backyard, it becomes readily evident if this has happened to rocks, in which case, they don't need to be used to establishing an order of fossils. There are plenty of rocks that are perfectly smooth and flat to pick from, we have the entire Earth full of them.
Some deniers might also say that maybe all of these layers were instantaneously laid down all at once. And while that's physically impossible (they can't instantly all deposit at once, else they'd be inside one another as opposed to on top or bottom of one another), We also have an uncountable quantity of features that also suggest a long expansive time between deposition of these major bodies of rock. Such as having paleozoic angular unconformities for example. Or having faults that only cross cut certain layers and not others.
To describe, see the Wyoming diagram above where the orange and brown shallow layers aren't obstructed/offset by faults, but the lower green layers are. This difference suggests suggest that there was a temporal separation between when the lower layers were deposited, when the fault offset the lower layers, and when the upper layers were deposited.
And this is just off the top of my head, but it's just obvious to anyone who studies this stuff that these layers were not all laid down within seconds of each other as some young earth Creationists seem to believe.
We also have features like slicken sides, cataclastic deformation and ophiolites, other forms of unconformities, and even innumerable trace fossils and footprints and nests and complex borough networks and All sorts of things found in between and all throughout these layers that suggest that time passed between their deposition.
We also have metamorphic facies produced by specific pressures and temperatures that we can use to further understanding the history of a region, particularly during regional metamorphosis.
And given that time has passed between these layers, any amount of time even if it were just a year or two is enough to establish a fossil succession. And obviously there's a ton more information that helps us really get down into how we know that the planet is far older than 6,000 years and is in actuality billions of years old. But strictly speaking about transitional fossils, these basic fundamental concepts are all anyone needs to establish the fact that the fossil succession truly exists. And that is step one to understanding the theory of evolution as well. If we want to take this approach. Because when we really start to look at this order of fossils, we come to find that theory of evolution explains their order perfectly.
Anyway, the point is that a basic understanding of geology is needed to understand the theory of evolution. And if you don't understand these basic concepts, then you evolution simply won't make sense to you.
