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Comment by zach_miller | Hacker News Reader

They did.

A common misunderstanding of evolution is that it means a population of X becomes a population of Y. In actuality, it means a population of X becomes a population of X AND Y. If X and Y aren't competing for the same resources (speciation commonly happens to take advantage of a different set of resources), then there is no reason they can't coexist indefinitely.

I blame Pokémon for this erroneous view of evolution. Your Charmander has evolved in to a Charizard!

This made me laugh but also made me think about what does and does not evolve. Sharks and the coelacanth fish are often mentioned as modern animals that “have never needed to evolve”. Guess it’s just based by comparing current physiology/structure to what fossil records can be found. Of course “everything evolves” but that depends on a frame or reference in time

Sharks and coelacanths have evolved exactly as much as humans.

The difference is that they have kept a more-or-less constant body plan, and evolved details less easy to see.

The monkeys have also evolved exactly as much as we have. Again, it is less easy to see the evolved differences from their ancestors, because their bodies are so superbly adapted to their way of life and so have not changed much.

This is not true. They have not evolved/derived as much for a number of reasons including differing mutation rates, minimal environment change, selection against adaptation, etc.

It is not visible vs invisible changes that progress at some fixed proportion to reproductive rate; that is a gross oversimplification and conceptually inaccurate.

See e.g. Sewell Wright’s fitness landscapes.

Surely this is wrong if we're talking about genetic drift which has no reason to be linear with time ?

It's also wrong if you're considering the number of generations available for evolutionary selection pressure. But it's less wrong than what it's rebutting, so I'm happy to say it's rhetorically correct. (It'd need to be a bit more precise to be pedagogically correct, à la lies to children, in my book, because it is still misleading.)

Acknowledging, generation time is a legitimate counter.

Isn't 'need' the wrong word.

They just haven't happen to produce an advantageous mutation ..... That changes their form enough to cross some arbitrary line where we would define 'evolving'

> everything evolves

Not necessarily, some things go extinct.

Or, evolves in to what?

Perhaps we can be certain that every changes. Maybe that's cyclical too.

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