Symetry

[CabVet]

Not necessary. When close to the ground, there is still plenty of food in the air.

No, there is not.

 

[CabVet]

Sense of direction could be controlled by the central nerve system. There is no need of directional mark on the external form.

Or animals can roll their eyes, like this:

 

[juvenissun]

No, there is not.

A life which can float in the air of the earth does not take much volume and weight. For such kind of life, oxygen, nitrogen, water vapor and dust are probably enough for their survival.

With that said, it would be interesting to see what is the preferred shape of their body. I bet it is more likely to be spherical.

 

[juvenissun]

As soon as the organism tends to travel with one part of its body going first, then a front is established.

Of course.

The idea of a spherical body is that the "front" can change instantly toward any direction. Otherwise, I don't see why would any animal want to be spherical.

So, may be the existence of disk-shape animals is a good evidence against evolution.

 

[CabVet]

A life which can float in the air of the earth does not take much volume and weight. For such kind of life, oxygen, nitrogen, water vapor and dust are probably enough for their survival.

With that said, it would be interesting to see what is the preferred shape of their body. I bet it is more likely to be spherical.

You are wrong, there are not enough nutrients suspended in the atmosphere to sustain life.

 

[juvenissun]

You are wrong, there are not enough nutrients suspended in the atmosphere to sustain life.

What else do they need? Maybe I forgot to count the sunlight.

 

[CabVet]

Of course.

The idea of a spherical body is that the "front" can change instantly toward any direction. Otherwise, I don't see why would any animal want to be spherical.

So, may be the existence of disk-shape animals is a good evidence against evolution.

LOL! Now after all the goalpost moving we came full circle. First, evolution was wrong because there were no spherical animals, which according to you was the "perfect" shape for an animal. Now, after we showed you there are plenty of spherical animals, the existence of such animals disproves evolution. You really have take your pick and stick with it.

By the way, disk shaped animals don't have "fronts", they move in any direction.

 

[CabVet]

What else do they need? Maybe I forgot to count the sunlight.

They need nutrients in addition to sunlight and there are not enough nutrients suspended in the atmosphere to sustain life. Of course there are bacteria flying around all the time, but they either 1) fall to the ground because of the effects of gravity, or 2) if they are and stay high up for long enough they starve due to the lack of nutrients.

 

[Wiccan_Child]

Lol, of course not, you only know how to make theory sound like its your own.

I only know how to make theory sound like it's my own. Right. When, pray tell, have I tried to pass of a theory off as my own (except in that rare instance when it is my own)?

And for the record, I didn't understand the last part of your previous post because it didn't obey the usual rules of grammar and syntax.

"because it just so happens that looking for processes in a world of a changing ecology does actually save some time... as if "focusing" on its own wouldn't - when we already know that!!"

Does anyone else want a stab at decyphring this? Am I, in fact, having a stroke?

Not that there's anything wrong with that, if you can still apply yourself in some way.

Someone intelligent like you could probably have a crack at inventing power amplifiers (as opposed to just voltage) or something like that.

I'll get right on it.

 

[juvenissun]

They need nutrients in addition to sunlight and there are not enough nutrients suspended in the atmosphere to sustain life. Of course there are bacteria flying around all the time, but they either 1) fall to the ground because of the effects of gravity, or 2) if they are and stay high up for long enough they starve due to the lack of nutrients.

You are talking about known fact. I am talking about possibility.
Hey, wake up !

 

[juvenissun]

LOL! Now after all the goalpost moving we came full circle. First, evolution was wrong because there were no spherical animals, which according to you was the "perfect" shape for an animal. Now, after we showed you there are plenty of spherical animals, the existence of such animals disproves evolution. You really have take your pick and stick with it.

By the way, disk shaped animals don't have "fronts", they move in any direction.

In reality, they do. Everyone has a front. That make the disk shape meaningless.

Hey, many fishes are disk shape, only being vertical instead of horizontal.

So, pull everything back. The bilateral shape of most animals is not more advantageous according to the idea of evolution. It should be either no symmetry, or be perfect in symmetry.

Furthermore, I would imagine a symmetry higher than 2-fold would be even better than the most common 2-fold. How about we have 4 arms, 4 legs and 4 faces? Would that be better?

 

[CabVet]

In reality, they do. Everyone has a front. That make the disk shape meaningless.

Hey, many fishes are disk shape, only being vertical instead of horizontal.

So, pull everything back. The bilateral shape of most animals is not more advantageous according to the idea of evolution. It should be either no symmetry, or be perfect in symmetry.

Furthermore, I would imagine a symmetry higher than 2-fold would be even better than the most common 2-fold. How about we have 4 arms, 4 legs and 4 faces? Would that be better?

There is a name for that, it is called pentaradial symmetry, 5 arms:

But you still have a big misconception: evolution is not about becoming better, it is about becoming adapted.

 

[Tiberius]

Of course.

The idea of a spherical body is that the "front" can change instantly toward any direction. Otherwise, I don't see why would any animal want to be spherical.

So, may be the existence of disk-shape animals is a good evidence against evolution.

But if the sense organs are concentrated on one part of the organism's body, then the organism would need to rotate in order to keep them pointed in the direction of travel. And the need to be spherical would be eliminated.

 

[juvenissun]

There is a name for that, it is called pentaradial symmetry, 5 arms:

But you still have a big misconception: evolution is not about becoming better, it is about becoming adapted.

That means better.

So, tell me what is the advantage of having this 5-fold symmetrical body?

 

[juvenissun]

But if the sense organs are concentrated on one part of the organism's body, then the organism would need to rotate in order to keep them pointed in the direction of travel. And the need to be spherical would be eliminated.

I guess so.

So, if the body is circular, then all the controls should be right at the center.

To elaborate, the controls of any symmetrical body (include bilateral) should always be at the center of symmetry.

From this point of view, the earth does not really have any true spherical or circular shape animal.

 

[Gracchus]

That means better.

So, tell me what is the advantage of having this 5-fold symmetrical body?

“The development of an echinoderm begins with a bilaterally symmetrical embryo, with a coeloblastula developing first. Gastrulation marks the opening of the "second mouth" that places them within the deuterostomes, and the mesoderm, which will host the skeleton, migrates inwards. The secondary body cavity, the coelom, forms by the partitioning of three body cavities.
Upon metamorphosis, each taxon produces a distinct planktonic larva, which varies in shape among the classes. Larval stages with prominent "arms" are often referred to as pluteus larvae (often with a prefix to denote taxon).
The left hand side of the larva develops into the adult organism while the right hand side eventually being absorbed; the left hand side typically becomes the oral plate.”


Echinoderm - Wikipedia, the free encyclopedia


So there is evidence that the radially symmetrical echinoderms evolved from a bilaterally symmetric ancestor. Sessile forms seem to prefer radial symmetry. In the Cnidaria, for instance, the jelly fish probably evolved from the sessile corals.
Moreover, Echinodermata usually exhibit a secondary bilateral symmetry. A starfish, for instance will generally move preferentially with one “leg” favored as the “front”. And some “sand dollars” show obvious bilateral symmetry. It is thought by some that echinoderms were adapted to a sessile life, Crinoidea, attatched to the sea floor, and later developed free living forms, and those free living forms, starfish, urchins, et alia, are re-evolving bilateral symmetry.

So, if the body is circular, then all the controls should be right at the center.
To elaborate, the controls of any symmetrical body (include bilateral) should always be at the center of symmetry.

"They (echinoderms) have a simple radial nervous system that consists of a modified nerve net — interconnected neurons with no central brain (although some do possess ganglia). Nerves radiate from central rings around the mouth into each arm or along the body; the branches of these nerves coordinate the movements of the organism."
Echinoderm - Wikipedia, the free encyclopedia

From this point of view, the earth does not really have any true spherical or circular shape animal.

Probably not.

To recapitualate: It seems that the echinoderms were originally free swimming and bilaterally symmetrical, became sessile and radially symmetrical, and then became free-living again, and seem to be re-evolving, in some forms, bilateral symmetry.

 

[juvenissun]

“The development of an echinoderm begins with a bilaterally symmetrical embryo, with a coeloblastula developing first. Gastrulation marks the opening of the "second mouth" that places them within the deuterostomes, and the mesoderm, which will host the skeleton, migrates inwards. The secondary body cavity, the coelom, forms by the partitioning of three body cavities.
Upon metamorphosis, each taxon produces a distinct planktonic larva, which varies in shape among the classes. Larval stages with prominent "arms" are often referred to as pluteus larvae (often with a prefix to denote taxon).
The left hand side of the larva develops into the adult organism while the right hand side eventually being absorbed; the left hand side typically becomes the oral plate.”


Echinoderm - Wikipedia, the free encyclopedia


So there is evidence that the radially symmetrical echinoderms evolved from a bilaterally symmetric ancestor. Sessile forms seem to prefer radial symmetry. In the Cnidaria, for instance, the jelly fish probably evolved from the sessile corals.
Moreover, Echinodermata usually exhibit a secondary bilateral symmetry. A starfish, for instance will generally move preferentially with one “leg” favored as the “front”. And some “sand dollars” show obvious bilateral symmetry. It is thought by some that echinoderms were adapted to a sessile life, Crinoidea, attatched to the sea floor, and later developed free living forms, and those free living forms, starfish, urchins, et alia, ar re-evolving bilateral symmetry.

"They (echinoderms) have a simple radial nervous system that consists of a modified nerve net — interconnected neurons with no central brain (although some do possess ganglia). Nerves radiate from central rings around the mouth into each arm or along the body; the branches of these nerves coordinate the movements of the organism."
Echinoderm - Wikipedia, the free encyclopedia

Probably not.

To recapitualate: It seems that the echinoderms were originally free swimming and bilaterally symmetrical, became sessile and radially symmetrical, and the became free-living again, and seem to be re-evolving, in some forms, bilateral symmetry.

Believe it or not, I actually read what you posted carefully.

Thanks.

 

[Tiberius]

I guess so.

So, if the body is circular, then all the controls should be right at the center.

To elaborate, the controls of any symmetrical body (include bilateral) should always be at the center of symmetry.

From this point of view, the earth does not really have any true spherical or circular shape animal.

Have a read of The Ancestor's Tale, The Ragwaorm's Tale.

 

[NailsII]

So, if the body is circular, then all the controls should be right at the center.

How so?
If we designed them, we might think so.
What if the control centre was actually like a halo just inside the organism?

To elaborate, the controls of any symmetrical body (include bilateral) should always be at the center of symmetry.

Why?
Your speach control centre isn't in the centre of your mouth or throat or even brain.
I fail to see the logic of giving the centre any kind of special respect.

From this point of view, the earth does not really have any true spherical or circular shape animal.

The earth doesn't have any truly symmetrical animals, does this mean something as well?

 

[juvenissun]

How so?
If we designed them, we might think so.
What if the control centre was actually like a halo just inside the organism?
Why?
Your speach control centre isn't in the centre of your mouth or throat or even brain.
I fail to see the logic of giving the centre any kind of special respect.

The earth doesn't have any truly symmetrical animals, does this mean something as well?

I was only respond to the position of biological control in a symmetrical body. If the control unit is not a point located at the center of symmetry, then it will be internally asymmetrical and that will make the locomotive action of the symmetrical body asymmetrical.

For a bilaterally symmetrical body like human, there is a "plane" of symmetry. So the controlling parts can be distributed on that plane in any geometry and do not have to worry about the interruption to the bilateral symmetry.

By saying that, I understand our heart is not located on the central plane of our body. And I am not sure what would be the special effect of that skewness to our physiology. What would happen to us if the heart is skewed toward the right side of the body?