Proportion, a giraffe could bite its own toenails

I posted this in the Gray Area, but feel that it belongs here...I could be wrong


I was contributing to another thread, well sort of, when I made a startling discovery.

This is how I came to this conclusion on the Gray Area thread concerning eyes being always on the head

Just a thought...one post stated that the eyes are close to the brain for speed of nerve transfer...surely if the optic nerve where 30ft long the time lag would be imperceptible.

Another...the eyes are at the front because creatures move in that direction...what about species of crabs they move sideways, don`t they.?
On crab anatomy it shows eye stalks and says that they are useful for directing food into the mouth...but creatures that have two articulations, shoulder and elbow, cannot help but hit the mouth...try it yourself, raise your arms to a crucified position then bend at the elbow towards the face, slap in the mouth.
on the crab articulations...I think that this could even apply to the four legged creatures, like a giraffe, maybe it too could reach its mouth with a toe if it was anatomically possible to do so, a question of proportion.



I do not know how this worked out....comments

obviously its for grooming purposes. giraffes love black tie events and would not be caught dead with uneven toenails.


theres probably some benefit to being able to reach your face even if you dont have hands. ive never noticed that before. interesting.

NOTE: most people in decent shape can bite their own toenails

Nice reply...my kids are always biting theirs.

But how does this stand in the arena of explanation.? is there an evolutionary reason for this or is it a design.?

If something as important as being able to feed yourself appears in the osteology of a vertebrate unable to use these structures for that purpose, I would guess that other structures must be following a like pattern of proportion but at what level I am unsure.

any ideas.?

I think that the eyes are on the front of the head, because in early creatures that was the most efficient place for them to evolve. On creatures where that may not be the most practical place, it's not enough of a detriment for it to be selected against.

Oddly enough, a giraffe has the exact same amount of neck bones as a human being.

Just thought I'd toss that in there to see if it helps.

Not sure if it helps but it is interesting, looked it up...a human and a giraffe have the same amount of cervical vertebrae, 7 like other mammals, it is odd that all mammals share this number.

Other vertebrate species vary greatly but some are still quite close, a swan has 22-25 and a sloth has 25.

Just been looking for the evolution of a giraffe, actual fossil remains of transitional forms...I can`t find any, the whole thing is very sketchy.

Found an interesting piece on Richard Dawkin's persuasive illustrations,

From Dawkins' portrayal one gets the impression that the step from okapi to long-necked giraffe is slight, and the text reinforces this impression. The placement of the okapi above the giraffe in Dawkin's book also makes it appear larger than if it were placed on the same level as the long-necked giraffe.

...no suprise there then, Dawkins is a light-weight.

reply to post by ironbutterflyrusted

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Compared to whom? Do you know why Richard Dawkins is famous? What his contribution to biology has been? He changed the way we look at life and its evolution. Would you call that lightweight work?

You may have noticed that light travels faster than sound. The first signal of impending danger or opportunity is therefore likely to be a visual one. The quicker one responds, the better, so evolution has arranged matters so that as little time as possible is lost in getting that signal from the eye to the brain. That is why all animals have eyes on their heads, or at best on stalks.


Why do you think so? Neural impulses don't travel instantaneously.

Source

As for eye position, predators and arboreal animals tend to have eyes at the front of their heads because this is the best position for stereoscopic vision, which is necessary for judging distances. Herbivores, which are usually prey, tend to have eyes located where they can best spot threats against themselves - on the side of the head. Animal eye location


Crabs live in water, and they don't eat like people.

Instead of trying to work these things out for yourself, why not read up on them?

[edit on 10/7/09 by Astyanax]

Mr Dawkins tries to talk up a cursory view of genetics, propped against a backdrop of metaphysics...if you want me to provide an extensive list of Philosophers that surpass the great knowledge of Mr Dawkins I would be happy to do so...Mr Dawkins is supposed to be a rational scientist, so why does he borrow heavily from Philosophical debates.?

I am quite familiar with anatomy and physiology...and basic physics.

The transmission of impulses is not at any time 10ft, It is in the range of tens of feet a second...have you ever been aware of a time lag in events.? No, how could you, but you will have been aware of the stimulation of cones and rods when leaving a dark room to a sun filled room.

I think that you are confusing a motor neuron with the optic nerve, the optic nerve is wired directly to the brain, transmission travels in the region of 400 miles a second.

Agreed crabs do not eat like people but they have the mechanical proportions to reach the mouth....how would Mr Dawkins account for this trend.?

By what evolutionary events can the fact that the leg of a giraffe is proportionate to the length of neck be explained.? other than some master gene ochestrating the whole event....I would stay away from Mr Dawkins when pursuing the answers, the giraffe is obviously not his strong point...by the way, what are his strong points.?

I suggest that you read up on things.

Do so.


Faster than light. What rubbish.


Any animal that puts food in its mouth with its limbs will have such proportions.


I believe he is quite attractive to the opposite sex. He has other strong points also, but none that you would be likely to understand.


What things?

The answer seems a bit obvious ...A giraffe is a herbivore and mostly eats from trees. But when there is nothing at tree height to eat then they can eat grass off the ground. The body is in the middle so the creature has the greatest range of movement between the 2.

They drink out of rivers and lakes so it had to be able to get its head down that low.

[edit on 15-7-2009 by VitalOverdose]

A sloth is a mammal.



Not sure what your eyes adjusting to light has to do with optic nerve transmission speed. The two are mostly unrelated systems. Also, it's impossible to be aware of a time lag in things you see, considering you only "see" something once the image has been processed by your brain.

Also, there are mammals who's legs are too short to reach their mouths. The Weasel comes to mind.

I did not mention the transmission being faster than the speed of light.

The sloth just caught my attention.

Agreed, many others cannot reach their mouths, but the giraffe has lengthened in the legs and the neck, according to evolution, and has maintained proportion...how could this occur through random mutations.?

Yes the head can reach the ground and the body is in the middle...what does that prove.? Heraclitus,The road up and the road down is one and the same.

I was using the cones and rods as an example of lag...but you could not perceive a pause in light transmissions because you would treat it as your natural sight, how could you know any different.?

reply to post by ironbutterflyrusted

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If his neck was shorter than his legs he would be able to reach the ground without kneeling which would put it at risk from predators.

If its legs were shorter than its neck then it would fall over forward if it tried to drink water or graze because it doesn't have a longer body or a larger tail to counter balance.

Its a simple matter of balance

Could you help with these questions.?

The random mutation of benefit to the proto-giraffe was a long neck. Natural selection, favoured the long neck, these individuals were healthier and possibly more attractive to the females, the likelihood of breeding increased,thus passing the propensity for the long neck mutation to the next generation to be used again...is this how it is explained by Darwinian devotees.?

Did all the food disappear at ground level.? why were the trees unaffected.?
The gestation period of a giraffe is near to 15 months and only 1 offspring is produced, this problem with food at ground level must have lasted a long time, is there evidence for this.?

Did all the ground species migrate or become extinct, in this evironment that favoured long necks.?

Did these particular trees grow really quickly, from seed to 14ft in no time at all.? or did they grow like normal trees, slowly.?

If the trees grew at a normal rate, how did the small trees become established.?
Why were the small young trees not eaten before reaching maturity, thus cutting down the number of trees for future generations.?

How abundant were the favoured trees.?

Was there competition, from species already able to move through the thorns, climbing in the trees.? or climbing/landing on the fruit trees, when availiable.?

Ground grazing is as dangerous to a giraffe as drinking, when the head is down they are vulnerable to attack. So the long neck can only be seen as an advantage when eating the upermost leaves.

When the giraffe was evolving from a smaller species, every part of the anatomy had to develop too. Why did the legs and neck develop at a faster rate.? or continue to grow when the main cavity of the body had ceased.? is not a large size bad when food is short.?

Is an overall controlling gene directing the other genes.?, Is the controller responsible for leg growth also in control of the cervical vertebrae and spinal chord.? blood vessels, heart etc

If two or more controlling genes, where responsible, how do they influence each other.? and how often do they deviate from normal production.? is there evidence of this occurrence, in nature.?

Why did the neck stop growing, just short of reaching the ground comfortably.?

The legs and the neck both have quite unique structures for dealing with variations in blood pressure. How did these structures evolve at the same rate as the neck and legs.?

When the neck and legs reached a certain length...a critical size, what size would that be.?, how did the genes responsible for everything involved in blood circulation/vessels initiate this much needed elaboration, in the next generation of slightly longer neck/leg giraffe.?

How did this mutation provide a system whose function is effective/proportianate to the demands of neck/leg length, before that length has been realised.?

...just a few thoughts.

These are all very good thoughts.

Im no expert on this subject so these are mostly just my opinions based of things ive read and watched in vids. I know the developement of the giraffe is always one of the most debated points in the evolution theory . Some of the latest research in this subjects suggests that animals can change their genes during their lifetimes.

I think the head has always been able to reach the ground during the development of the giraffes long neck as water is probably just as important as food and the body always stays in the center because this provides the greatest range of movement while still maintaining center of gravity good enough to allow then to run away from preditors.

This is my best guess..
Maybe Giraffes were just horse's at one point in time, mainly grass eaters. If they do well as a species as thier numbers start to increase there will be less and less grass to eat so the ones who can eat other stuff like bush's and tree's find it easier to get food than the others . Then as they do well as a species the ones with the longest necks find it easier to get to their food source and are more likley to reproduce than the ones with shorter necks. I dont think the genes make a decision about the length of the neck. If the neck is to long for the body and makes the creature unballanced they probably wont even make it to adulthood. I get the feeling that when Giraffes had shorter necks there might have been a population explosion as they were one of the only large ground animals eating from tall bush's and trees. Giraffes always hang about in heards so it wouldnt be long before preditors would start hunting the early Giraffe's every day ,picking off the ones less able to spot them coming or defend themselves. The kick from a fully grown Giraffe can easily kill a lion apparently. I would guess that this process of natural selection would be a lot quicker than the first part of their evolution.

- Genetic error gives 1 creature advantages over its relatives.
- If the advantage is large enough there is a population explosion of that new species.
- Preditors then target the new species as daily food source.
- As numbers of new species fall only the ones better able to defend themselfs survive to mate. Or the species become extinct.

As the second half of my theory would happen in a very short space of time compared to the first part it would be very hard to find fossil evidence of the actual change from one species into the next. 1 min you would have a lot of one species and then not many at all + new species suddenly appears.


[edit on 20-7-2009 by VitalOverdose]

sry double post
[DELETE ME]

[edit on 20-7-2009 by VitalOverdose]

Vital you are pretty wise. Your examples helped me get a good visual picture going. I liked the water and balance examples.

No. Animals compete preeminently with members of their own species. Giraffes are animals that eat leaves off trees. Longer-necked giraffes could reach leaves shorter-necked ones couldn't. This gave them a selective advantage, so they survived and the shortnecks died out.

All your succeeding questions are thus rendered invalid,. They reflect a lack of understanding concerning how evolution by natural selection works.


Precisely. And that will do.

I think ironbutterflyrusted asked the questions to get a better understanding of the subject in the first place so they are far from invalid. You should remember the process of evolution is not consistant in all animals and at the end of the day is still a theory.

This is after all a forum for debate..

[edit on 23-7-2009 by VitalOverdose]