How does a baby bird know to act like a poisonous worm when a predator shows up? The answer is genetic memory, but how does it work? How does it get encoded into dna, passed down, and executed.
In: Biology
There’s not a super direct answer to this because we don’t know everything about nervous systems (i.e., the brain, brain stem, peripheral nerves). But the basic answer is that the “memory” isn’t for a specific behavior. It’s for specific proteins and configurations of proteins and stuff like that.
An analogy is a book having “memory” of a story. It doesn’t actually. It’s just a bunch of shapes. The shapes are a code that have to be decoded through the process of reading. Then you get the story, despite each individual code only being a single, simple word.
Similarly, DNA has codes for proteins. Individually, they’re useless, just like if all I sent to you was the letter Y with nothing else. If you read them wrong (errors in making the proteins and stuff), they’re useless, like sdjalkdfs. But in the right sequence, you get a bird that wiggles like a worm.
Why did that sequence become common? Evolution. Those are the birds that survived and reproduced. So they’re the ones who stuck around for you to see today.
How do new complex behaviors emerge from DNA memory? Mutation and some other stuff I forget at the moment. The behavior may have been less notable at first. And over time, evolutionary pressure “selects” the most worm-like bird behavior.
Oh yeah, once the brain is whole and “on,” the animal can learn, too. So sometimes the behavior is just a predisposition to learning a specific thing. Like humans are predisposed to learn language.
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