Biological evolution and languages changing over time. They're so similar that we can create a lot of parallels between both that are useful for both disciplines:

• "species" as defined by the shared genetic pool vs. "language" as defined by mutual intelligibility
• ring species vs. dialect continuum
• horizontal gene transmission vs. borrowing of vocabulary, grammatical features, and phonological features
• cladograms are pretty much the same, including their pros and cons
• latest common ancestor being a hypothetical construct vs. "proto-" reconstructions (e.g. Proto-Romance vs. Latin)

Because the underlying reasoning is exactly the same. You have an abstract system that piles up small changes over time, and those changes may be shared across different populations within that pool.

You need to watch out for a few differences too. For most part, biological evolution is driven by the interaction between phenotype and the environment, while linguistic evolution is more often than not some mutation with no intrinsic selective value, piggybacking on something outside language (e.g. speaker prestige).

Aren't Sudoku and protein folding essentially the same problem? Like, if you could write a computer program to solve sudoku in polynomial time, you could adapt that solution to solve protein folding problems in polynomial time? Or something like that.

Someone who is smarter than me, please chime in.

Democrats and Republicans.

I'll take my downvotes like the lady I am.

Still true, though.

It took me a while to figure out that an over-the-counter sleep aid and the Benadryl I would buy for allergy symptoms were, in fact, exactly the same drug, Diphenhydramine, packaged under different names.

Apples and oranges.

The twice a year time change and more heart attacks.

Having a successful marriage and eating an orange.