[marktwain]

“As the Earth’s orbit slowly changed” The earth’s orbit around the sun has not changed.

The Earth's orbit may not have changed, but the Earth's orbit around the sun does change in a periodic way, over thousands of years.

[Hot Tabasco]

Several years ago divers found evidence of a prehistoric hunting camp beneath Lake Huron, created when the lake was about 250 feet lower and caribou used to migrate thru there.......

[SunkenCiv]

Thanks marktwain for that link. Regarding Milankovitch cycles:

Variations in the Earth's eccentricity, axial tilt, and precession comprise the three dominant cycles, collectively known as the Milankovitch Cycles for Milutin Milankovitch, the Serbian astronomer and mathematician who is generally credited with calculating their magnitude. [Milankovitch Cycles and Glaciation]

The tidal transfer of momentum pushes the Earth away from the Sun (from both sides), in the same way that the Earth pushes away the Moon (and prior to its loss of rotational energy, the way the Moon used to push away the Earth) which means that, over time, the Earth has been moving away from the Sun, and continues to do so. This has had a longterm impact on the length of the sidereal year and the angular velocity of the Earth (the farther we get away from the Sun, the slower it goes. Don't argue with me about it, argue with Kepler). IOW, the orbit of the Earth isn't fixed and immutable, even without taking catastrophes into account.

For axial motion fans, look up Chandler Wobble.