Selective advantage and genetics

[pioneer]

Ever since I could remember, I associated selective advantage with an improvement in genetics. But quite recently, a basic observation seems to indicate that selective advantage can also come from regressive genetics.

 

The easiest example to see is to compare the dinosaurs to the mammals. Most would agree that mammals have more advanced genetics. The data indicates that during the latter part of the dinosaur's dominance, mammals had already evolved, yet the dinosaurs had selective advantage since they remained at the top of the food chain. What it amounted to was less evolved genes having selective advantage over evolved genes.

 

If one was a mammal in that environment, progressive genetic traits could actually create a selective disadvantage. For example, additional rapport with the environment for food exploration could result in curiosity killing the cat, as dinosaurs and snake sit very still waiting in ambush. Peditor dinosaurs would also hear rustling of sticks for easier prey. Selective advantage would require the mammals dumb down and stay still so they can ambush smaller creatures that walk by.

 

Increases sensitivity in the skin and fur which is important for awareness, although genetic advanced, would make one more vulnerable to cuts and pain. Selective advantage would go to thick leathery hides with very few nerves. A mammal would have selective advantage if could deevolve their genes more like the tough skin of a lizard. This would make you less vulnerable to dinasaur attack/cuts and prevent pain from giving away you position while you try to heal.

 

Even a warm rapport with the environment, which is advanced, could get one into all types of problems with dinosaurs having selective advantage. Selective advantage would require regression to almost cold blooded.

 

In a world were regressive dinosaur genes had selective advantage, the selective advantage among the mammals, within that environment, would favor regressive genes. The exception may be sensory improvement. But behavioral genes would give selective advantage to regressive genes.

 

As a modern example, the human mind is the most evolved feature. Dictators like Stalin, had a intellectual purge, so the environment would favor more regressive behavior associated with violence. The selective advantage was not associated with progressives genes, but regressive.

 

The idea of selective advantage equaling genetic advancement does occur but the history of dinosaurs and early mammals show the opposite can also be true, with selective advantage also going to the regressive genes.

[lucaspa]

Ever since I could remember, I associated selective advantage with an improvement in genetics.

 

That's the fallacy: placing a judgement call and "value" on a genome. In evolution, there is no such thing as "improvement" or "more advanced". Instead, the terms "primitive" and "derived" are used to describe traits. This eliminates the value judgement about which species is "advanced".

 

The data indicates that during the latter part of the dinosaur's dominance, mammals had already evolved, yet the dinosaurs had selective advantage since they remained at the top of the food chain.

 

Actually, mammals had evolved at the beginning of the Triassic. Both dinos and mammals evolved at roughly the same time. So, for 130 million years mammals lived in the "shadow" of the dinos with dinos occupying the ecological niches of larger animals.

 

What it amounted to was less evolved genes having selective advantage over evolved genes.

 

No, what it means was that neither mammalian nor dino genes are more "evolved". You place a higher value on mammals because you are one. That's the mistake.

 

If one was a mammal in that environment, progressive genetic traits could actually create a selective disadvantage. For example, additional rapport with the environment for food exploration could result in curiosity killing the cat, as dinosaurs and snake sit very still waiting in ambush. Peditor dinosaurs would also hear rustling of sticks for easier prey. Selective advantage would require the mammals dumb down and stay still so they can ambush smaller creatures that walk by.

 

A very poor "just-so" story. Think about it. There are snakes NOW, but that doesn't mean mammals have to be "dumb", does it?

 

In that particular environment, dinos did better at being larger animals than mammals. Part of it was the mobility. The first dinos were on two legs and could move faster than the mammal-like reptiles of the time. The second is physiology. In a warmer climate, being partly warm-blooded takes less energy than being completely warm-blooded. Thus dinos had less metabolic cost than early mammals.

 

Remember, EVERY trait comes with a cost as well as a benefit. In some environments the cost outweighs the benefit. In others, it is the other way around.

 

As a modern example, the human mind is the most evolved feature.

 

No, it's not. Again, a basesless value judgement. EVERY other species on the planet has just as long an evolutionary history as humans. EACH of them is just as "evolved". If you were an elephant, you'd think a trunk was the "most evolved" feature. If a dolphin, it would be sonar.

 

Just forget the "progressive" and "regressive" genes idea. Think instead of "advantageous" or "disadvantageous" traits and recognize that a trait is "advantageous" only in relation to the environment. Change the environment and what was "advantageous" becomes "disadvantageous". That is what all the studies on natural selection have shown.