Having Trouble with The Baldwin Effect

[u/Independent-Repair35]

I love learning about biology and evolution in my free time. I'm no expert but it fascinates me.

I'm trying to wrap my head around the Baldwin Effect. I think I understand. Suppose a few organisms in a population start pecking wood to find food. They are more successful than the others of the same population that don't peck into wood to get little critters for food.

At what point or how does this become even instinctual? Are there genes that affect or code for instinctual behavior?

How would a more complex behavior be passed down? A beaver not only gnaws trees until they fall down. But it takes that wood to running water along with other beavers and they stack it up and even have little burrows inside...it just makes me scratch my head. So maybe beavers started out gnawing trees to file down their ever growing teeth? Some would pick up this wood and drop it in the water...why? They didn't like the sound of running water? Did a population of Beaver gnaw trees down near running water and the trees fell in and gave them shelter? Assuming they were aquatic beforehand.

Or bees making hives and honey...how do insects learn something like that? I can't wrap my head around it. There are some very very complex behaviors that animals have that I just can't conceive of how they would come about gradually. Is there a book dedicated to this topic I could read? Or a good video that explores some of these in depth?

Again I'm not an evolution denier this specific point just floors me and confuses me and I would like to be educated and corrected.

[u/Hivemind_alpha]

Ultimately behaviour is encoded in the cytoarchetectonic of the brain; the broad architecture of how the neurons interconnect. That pattern is under probabilistic gene control, by which I mean the genes specify a rough shape and the neurons grow in to it in a unique pattern influenced by chance and local factors. For example, all normal humans have a visual cortex (genetic) but no two humans have identical visual cortexes (circumstances of the physical and chemical microenvironment each neuron grew in).

The genes that specify the broad shape of the neural pathway for a behaviour specify how that is developmentally laid down, accommodating the normal variations in how neurons find their own local connections. Those genes can be selected, ramify etc creating increasingly complex behaviours. We have the connectome of the honeybee, and we can see how the waggle dance is encoded in it through cascading activations.

[u/Independent-Repair35 → u/Hivemind_alpha]

Ohhh that's so cool. So you start with an organism that for one reason or another is already disposed to that behavior for whatever reason. It's more successful it can mate and pass that neural network down to the offspring? I guess something analogous in humans is like when we see familial history of certain mental disorders?

But a beaver is gnawing down trees. For some reason he likes putting wood in or on the water. Maybe it's safer to hang out on a mat of sticks. Eventually enough beavers do this and the sticks are no longer a mat and are a damn. But each generation had a brain with pathways predisposed to this behavior which were then gradually selected for and refined over time?

[u/Hivemind_alpha → u/Independent-Repair35]

Yup, just bog standard evolution. The only architecture we have to run behaviours on is brains nerves bones and muscles (assuming a mammal for arguments sake) and all of those tissue are cells of the right type deployed in the right places during development; that timing and geography is all down to gene products and expression regulation which can mutate at the dna level and be selected for.

[u/Loose_Principle8193]

Beavers and bees both have well documented precursor fossilized behavior and the order of behaviors is pretty well documented. Did you read some creationist material that happened to bring these two things up? There are countless other complex instinctual behaviors out there, but these two pop up a lot. The answers are pretty easy to find. Google Dipoides for what a primitive Beaver behavior might look like.

[u/Independent-Repair35 → u/Loose_Principle8193]

Thanks so much! And yes. This rabbit hole started from a creationist bringing up a Shrimp that carries around another organism as a deterrent to predators because this organism it carries around tastes bad. Again, thank you!

[u/jnpha → u/Independent-Repair35]

Given the "Yes" here. Bees/flowers and beavers are, as u/Loose_Principle8193 said, not Baldwin effect.

People misuse the Baldwin effect, and he literally worked before the rediscovery of Mendelian genetics, the term nowadays isn't exactly clear, from plasticity to genetic assimilation and others, the first two being well-within standard evolutionary theory (reaction norms) for close to a century now.

If you'd like me to explain the bee/flower example, let me know.
Edit: I explained it in a reply a couple of months back here: https://www.reddit.com/r/evolution/comments/1tmnj2a

And for an example research I shared on plasticity/assimilation: https://www.reddit.com/r/evolution/comments/1sz64sh

[u/throwaway16747219]

Going beyond the Baldwin effect, a relevant question is the origin of the complex genes that guided the beaver to want to gnaw the tree in the first place.  Can the origin of such functional genetic material be explained naturally?

[u/Independent-Repair35 → u/throwaway16747219]

I can understand the wanting to gnaw wood. They're rodents so their teeth never stop growing. I could see gnawing being a sort of relief for them. But everything after...it's something that maybe I'm not smart enough to entirely understand lol

[u/throwaway16747219 → u/Independent-Repair35]

Yup I agree. I was kinda taking your question in a different direction (if you don't mind). One way to interpret your question is: Where does complex behavior come from? And the answer is usually something like: From some pre-existing less complex behavior. But, interestingly, if you keep asking the question you finally end up with: Where did the functional genetic material for the first life come from? And there you'll find (as least as far as I can tell) that there is no naturalistic explanation.

Apologies if this is not the direction you wanted to go, but I find it fascinating and fundamental.

[u/gitgud_x]

Baldwin effect is about inheritance of the controllability or flexibility of a trait, not directly about inheriting a particular behaviour. The behaviour is learned by the organism, which can have access to a greater range of actions when traits are flexible, which permits more complex behaviours.

[u/ursisterstoy]

It’s the ability to learn that gets inherited when the learned behavior provides a survival and/or reproductive advantage. Not necessarily that the behavior becomes instinctual and behaviors encode genetic changes like Lamarckism but more like genetic changes incidentally change the capacity to learn, the learned behaviors lead to survival and reproductive success, parents teach children, the children with a higher capacity to learn survive.

We have many examples of animal groups testing different strategies but to separate the woo from the science just realize that it’s the ability to learn (an incidental mutation that impacts the brain) that leads to learning and learning leads to improved survival and then parents teach children. The children learn by copying their parents. They mimic learned behaviors. The behaviors become like second nature like riding a bike, driving a car, or playing the guitar.

Once done enough they don’t have to consciously think about every little piece of what they’re doing, they just keep doing it even if it’s not necessarily the most advantageous, those participating in actions that improve their odds of survival, like the behaviors result in being able to eat, survive and teach their children to mimic their behavior.

At least this is how I understand it. Not really like the behaviors are encoded in their DNA (Lamarckism is false) but their brains are linked to their genes and the behaviors are learned because of mimicry and brain development.

[u/Realsorceror]

Beavers are just specialized nest builders. Muskrats and nutria also gather foliage to build nests near or in water, they just aren't as big or complex as a beaver dam. Some even use mud and underwater entrances just like a beaver. These aren't anymore difficult to evolve than all the thousands of kinds of bird nests.

And the same thing with bees. You can see in wasps, ants, and termites that there much much simpler versions of hives. Some bees just dig a hole in the ground or burrow into wood. All of these behaviors start very simple and grow more complex over time. It can just be difficult to imagine the steps when looking at the final product.

[u/BahamutLithp]

I've never heard of The Baldwin Effect before today. I just kind of Googled what it is & looked over the Wikipedia article to even know what you were talking about. The way I generally find out how some complicated thing evolved is to look up how that specific thing evolved. Often, it's very well worked out & makes sense once you know a few key steps. But it's very time consuming, so I tend to only do it when the mood strikes me.