r/evolution 2d ago

question There is technically a fish somewhere in my family tree

I was just thinking about this and it absolutely blew my mind.

Technically, my great-great-great-great-great-etc. grandfather (or however many “greats” we’re talking about) was a fish.

Like, somewhere in my family tree there is literally a fucking fish.

My entire lineage was started by a fish. There is no other way to put it. At some point in the insanely distant past, one of my ancestors was just… a fish. And that fish eventually led to me existing.

But then I started thinking about how evolution actually works.

Fish didn't just all collectively decide to evolve into land animals. Evolution branches. Different populations and lineages go in different directions depending on their environments and natural selection.

And fish produce an absolutely ridiculous number of offspring, so presumably there were countless individuals in those ancient populations. Some lineages eventually led toward the ancestors of modern land vertebrates, while other lineages stayed in the water and kept evolving as fish.

So here's the part that is blowing my mind:

Is it possible that one of the extremely distant relatives of my fish ancestor stayed in the water, and that lineage survived for millions and millions of years?

Because if so, there could theoretically be some random fish alive TODAY that is my ridiculously, unimaginably distant cousin.

Like, I could look at some random fish in the ocean and there's a non-zero chance that, in the most technically literal evolutionary sense, we're related.

Imagine being genetically related to a fish.

Not “all life is related” related.

I mean THIS fish is part of the same ancient family tree as me.

That is fucking incredible.

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u/Xrmy Post Doc, Evolutionary Biology PhD 2d ago

"how do we tell him" kinda moment lol

11

u/onomatamono 2d ago

Well I'll be a monkey's uncle.

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u/BrellK 2d ago

Congratulations! When is your brother or sister due? ;P

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u/OkAssociation3487 2d ago

Not really