Separation from the inertial of the DNA

[pioneer]

This idea came to me this morning. The best way to explain my line of thought is with a well documented observation. The fossil data indicates that life began in the water (oceans) and eventually migrates onto the land to become the land animals. Let us look this evolutionary transition in slightly different way. After billions of years of life evolving in water, the vast bulk of the DNA had evolved to the needs of living in water. When animals begin to walk in land, this transition could only have represented a small fraction of the total genes.

 

What this says is the inertia of a billion years of genetic evolution to the needs of living in water, was more or less trumped by a small percentage of genes geared toward land. In other words, if evolution is a long slow process, and builds upon the past, we have the bulk DNA connected to this past, having a type of inertia, yet there was not enough inertia to prevent movement to land. Land has all types of new problem and needs that would not have advantage in water. So how can these evolve in water?

 

In terms of selective advantage, at the cross-roads of water to land, selective advantage should be connected to the genetic inertia of a billion years in water. Advantage at the level of DNA should pulled critters back in the direction of the water, since so much is already optimized. There is no advantage of a fish to jump in the boat. Yet, with a small amount of genes, the advantage for some critters goes away from the bulk onto the boat.

 

This suggests one of two things; Either there was larger than incremental change in the DNA to balance the inertia of the watery past. Or there is another mechanism which allows the inertia of the bulk DNA to become blocked, so the potential in fewer new genes has more leverage.

 

This might explain why evolution is so slow. The inertia of the bulk genes pulls backwards, until there is enough for forward leverage. This observation has more to do with major transitions than with cosmetic differences where the bulk DNA is still in control.

Edited October 19, 2010 by pioneer

[Edtharan]

First of all, there is no such thing as Genetic Ineretia.

 

This alone renders your proposition invalid. However there are also lots of other reason (even if genetic inertia existed) that counter act your proposition.

 

Land has all types of new problem and needs that would not have advantage in water. So how can these evolve in water?

This is false. There are many traits associated with land, that have distinct advantages in water.

 

For one, water does not always have a lot of oxygen disolved in it. This can be because the water is stagnent, or because as water warms up less oxygen can be disolved in it.

 

So, an aquatic animal living in such environments would have an advantage for being abel to get the oxygen they need form the air. As fish have swim bladders (which are a modification of their gut) that allow them to exchange air between it and their blood, then if the fish could use the swim bladder to get air from the environment into their swim bladder (gulping a mouthful of air and swollowing it) and then selectivly exchinging oxygen into their blood and carbon dioxide out of their blood, they could live more effectivly in these noramlly hostile environments.

 

Many fish do do this, and they use it for exactly this reason. But, this is an advantage that can be built upon to allow an animal to live on land (by allowing the to directly get their oxygen from the air without the need for gills).

 

Also,if an animal lives in an environment with shallow water, fins strong enough to move them in places where swimming is difficult, or imposible, will give them a selective advantage by allowing them access to areas that others can't go to escape predators, or access new sources of food.

 

As such strong fins would also be an advantage to an animal on lnad, this preadapts the animal to living on land, without having to have adapted to land in the first place. There are plenty of fish that live in this halfway place between land and water and they do have strengthened fins which allows them to move arund. It is also known that these fins evolved into our limbs as the fossil record show this clearly, and we can even see that the bones in fish fins have direct matches with bones in out limbs.

 

All this means that it is most certainly possible for an aquatic animal to have advantages for evolving traits that also happen to give them some faculty to living out of water, without directly having to make a big jump from aquatic to land dwelling. Even if your "Genetic Inertia" existed, these traits show a path that fits with your proposition of Genetic Inertia and allows animals to migrate onto land.

 

But as I said at the start: Genetic Inertia does not exist.

[pioneer]

I had just coined the term genetic inertia, which may be why it did not exist, if you did a google search. What I meant by genetic inertia is evolution builds upon previous genetics with the majority of systems remaining the same, as we add incremental changes. Evolution does not go from fruit fly into elephant in one giant leap, ignoring the genetic inertia of the fruit fly. The genetic inertia within the fruit fly remains, with evolutionary changes incremental. Even without changes, there is enough inertia to keep the fruit fly moving to the future. If the environment changes this inertia could make it extinct.

 

In the case of animals going from water to land, there are many advantages in the long term. But this is not the case in the short term. Fish have gills and can't benefit by the extra oxygen in the air, so leaving the water has no big advantage. If anything they will die quickly. There is also water retention/loss considerations, as well as mechanical problems connected to the extra weight out of water, etc. That is more than incremental change since it may require hundreds of coordinated changes most of which have little selective advantage in water, so they will not be passed forward in water.

 

The question becomes, how can you trump the genetic inertia of water, and go from water to land? This is where the brain comes in. The brain is designed to work within genetic parameters, but consciousness is not limited to the programming of a computer, but can learn. A deer may have the genetic instinct to run away. But at the same time, one can place the deer in countless environments and he can sort of improvise escape regardless of the terrain. The DNA does not have a program for every situation, but passes that off to the brain where the brain uses real time data and memory to improvise and learn.

 

Consider this scenario. A water critter is being chased by an aggressive predator. Since survival is key within the parameters of brain, one possible strategy is jump out of the water to get out of harms way. Even if there is little in the way of genetic inertia, with respect to living on land, this choice at the level of the brain can still be the lessor of two evils with respect to survival. If you stay in the water maintaining genetic inertia, you are food. If you jump out, you may live to breed another day. With the predator threat gone, his genetic inertia as a water critter, will sense a threat to life by being on land, so he wiggles into the water.

 

This simple brain intercession, now means the parameters of selective advantage have changed, since it will now include both land and sea. The random genetic changes that will now stick because of selective advantage, now has some genes connected to land.

 

If you look at migratory birds, their genetic inertia requires a given temperature range. Their migration is part of this inertia, since it allows them to maintain tighter environmental parameters such as temperature. But say an animal decided to migrate into a hostile environment, due to some intercession of the brain. This will cause the parameters associated with selective advantage to go into flux, against the original genetic inertia. New needs means new parameters for selective advantage. What comes to mind are apes are not migratory. Yet the pre-humans wandered northward out of Africa, such that the genetic inertia of being an ape, was placed into an evolutionary flux; brain intercession.

Edited October 22, 2010 by pioneer

[Edtharan]

I had just coined the term genetic inertia, which may be why it did not exist, if you did a google search. What I meant by genetic inertia is evolution builds upon previous genetics with the majority of systems remaining the same, as we add incremental changes. Evolution does not go from fruit fly into elephant in one giant leap, ignoring the genetic inertia of the fruit fly. The genetic inertia within the fruit fly remains, with evolutionary changes incremental. Even without changes, there is enough inertia to keep the fruit fly moving to the future. If the environment changes this inertia could make it extinct.

Inertia is a poor choice as it indicates a motion in a particular direction, and that without further input the system will keep heading in that direction.

 

What you are talking about is called a "Phase Space". That is a conceptual space that describes the adjacent posible of all mutations the orgnaism can have happen. This phase space will also describe the relative fitness that the organism would have if that particular set of mutations occured to it. In this phase space if there is a local maxima of fitness, then it will tend to keep the organism at that maxima.

 

So, yes, in evolution, the organisms always move to an adjacent possible location within the phase space of posible organisms, but it is completely wrong to call this inertia, it is a completely different concept. The reason beiong is that an organism in a phase space has no prefered direction of movemnt. That is it can be moving in one direction within the phase space and then completely change direction with as much influence as it takes to keep it movig in the same direction as it was. If looked at in terms of inertia, then it is actually an inertialess environment (with inertia an object in motion tends to stay in motion and an object at rest tends to stay at rest, but in this phase space an object in motion instantly comes to rest unless an outside force acts on it).

 

In the case of animals going from water to land, there are many advantages in the long term. But this is not the case in the short term. Fish have gills and can't benefit by the extra oxygen in the air, so leaving the water has no big advantage. If anything they will die quickly. There is also water retention/loss considerations, as well as mechanical problems connected to the extra weight out of water, etc. That is more than incremental change since it may require hundreds of coordinated changes most of which have little selective advantage in water, so they will not be passed forward in water.

You are only looking at aquatic environments that the organisms are already weall adapted too. But you are forgetting that not all environments are perfect. Tak for example some of the rivers here in Australia (and other places around the world). We experience droughts and wet times. In the wet times the rivers run just like any other river system does, fish and other aquatic organisms are living in a watery paradise (well may be for them ).

 

However, we also experience droughts and at these times the rivers can almost dry up, leaving only seperated pools of water and the river does not flow at all. In these conditions these pools, without turbation to stir up the water and introduce oxygen will become quite anoxic. In these cases fish have to gulp in air or they will suffocate. Fish that are better adapted for this will do better than others that are not well adapted. ANd, because the river floods and the fich can move aorund, they can not be certain to end up in a large pool of water (so over time better air breathing will -and has - evolve).

 

So here is a clear, real world example where your argument fails. Your argument is that situations don't occur where aquatic animals are forced to adapt to non-aquatic environments. Here is the wikipedia page for one such fish ( http://en.wikipedia.org/wiki/Queensland_lungfish ).

 

So, in the cases where water gets stagnated in pools (or for other reasons) and becomes anoxic, then ther eis a clear benfit for adaptations that can be useful for getting about on land and your argument here is therfore incorrect.

 

The question becomes, how can you trump the genetic inertia of water, and go from water to land? This is where the brain comes in. The brain is designed to work within genetic parameters, but consciousness is not limited to the programming of a computer, but can learn. A deer may have the genetic instinct to run away. But at the same time, one can place the deer in countless environments and he can sort of improvise escape regardless of the terrain. The DNA does not have a program for every situation, but passes that off to the brain where the brain uses real time data and memory to improvise and learn.

Again, as Genetic inertia does not exist and is an incorrect concept to use when thinking aobut evolution at all, your arguments here make no sense.

 

However, you are again making the assumption that all aquatic environments are deep water. This is not the case. Shore dwelling animals can have an advantage by being able to avoid larger predators. However, shore environments are notoriously changeable (tides, waves, etc), so an animal that gets caught out would be in desperate straights.

 

In a tidal flats environment, such animals would experience periodic times of anoxia as the small pools are exposed to that sun and heat up (warm water holds less oxygen) and without waves to sitr up the water and introduce more oxygen. In these situations there is a clear advantage for organisms to be able to survive by breathing air and or moving in shallow water by using fins as limbs (where swimming is almost imposible). As these locations offer the organisms an advatage over deep water (no predators, etc) then ther eis a reason that these organisms will adapt to these environments. But, these adaptations needed to survive in these locations pre-adapt the organism for surviveing on land as they already are semi-land dewlling by this time.

 

Consider this scenario. A water critter is being chased by an aggressive predator. Since survival is key within the parameters of brain, one possible strategy is jump out of the water to get out of harms way. Even if there is little in the way of genetic inertia, with respect to living on land, this choice at the level of the brain can still be the lessor of two evils with respect to survival. If you stay in the water maintaining genetic inertia, you are food. If you jump out, you may live to breed another day. With the predator threat gone, his genetic inertia as a water critter, will sense a threat to life by being on land, so he wiggles into the water.

 

This simple brain intercession, now means the parameters of selective advantage have changed, since it will now include both land and sea. The random genetic changes that will now stick because of selective advantage, now has some genes connected to land.

Evolution does not work on the level of the individual, so this scenario is not useful. You have to look at whole groups of organisms and the allel frequencey within those groups. However, this type of thinking is understandable as a lot of natural history programs present this as evolution (David Attenborough is well know for it). It is a totally incorrect view and it probably is what has lead you to your confusions about evolution and how organisms evolve.