Richard> "Also, if gravity was low 200 million years ago, which, as you claim,
meant larger dinosaurs, how did they breath? Lower gravity mean less air."
Ramin> Speaking about increasing of Earth's gravity, my mean is a very gradually increase. As you see in article No. , a very small change of gravity can make lots effects on live animates. So my mean is this, in the past, the gravity was so small, as the atmosphere could be thin remarkably. The interesting this is this in despite of being small for gravity in the past, viscosity and pressure of atmosphere was more than is now. Because viscosity and pressure of atmosphere depends on type of molecules which form it, in addition to the amount of gravity. If atmosphere will be formed of heavy molecules, it's viscosity and pressure will increase. As we know, the combination of atmosphere has been constant from past up to now. High beeing of pressure in the past, is the same another reason for better living of giant animates. Also, the increase of pressure is the same factor which increases the growth speed of animates.
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Richard> What "heavy molecules" do you refer to? I can prove that you are wrong, Mars' gravity is 36% of earth and it's atmosphere is 0.6% of the earth.
Ramin> The pressure of earth's was a great amount when dinosaurs were alive, because of being a great amount of CO2 of atmosphere. CO2is a heave molecule. Gravity of Venus is 87 percent of earth's gravity, while, it's atmosphere's pressure is 92 time of the earth's one and it's reason is related to being CO2 a grate amount in it's atmosphere. So you see that the amount of atmosphere's pressure depends on type of atmosphere's molecules mainly.
As atmosphere's pressure increases, the growth speed of animates moves up.
Also, frequent presence of CO2 in atmosphere, causes to increasing of atmosphere's temperature. As you know, in ago of dinosaur earth's atmosphere was so warmer than is now.
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Ramin> * Why dinosaurs had a high growth speed?
Richard> How do you know they had a high growth rate? How many years did it take for a diplodocus to grow to full size and is that rate any different than present day whales or elephants? The only way to know for sure is to go back in time and actually seeing for ourselves. Since that is not possible ANY explanation is just speculation. But we start with speculations, that is normal, next you have to PROVE your speculation, so let's see the evidence.
Ramin> Researchers has concluded this, from tissue structure of dinosaurs' bone. If you think a little better, you'll conclude this too.
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Ramin>* Which environmental factor changes the growth speed of animates?
Richard> All kinds, O2 levels, food availability, temperature (bigger animals in colder regions is the norm), mating factors, preditor factors, and so on and so on and so on.
Ramin > You can't force an elephant to attain puberty in a short period by increasing of temperature and meal and amount of O2 and your mentioned factors. Also, you can't increase the growth speed of it's foetus (embryo) to generate in a short period.
Richard> Actually, you can. If you change the environmental pressures of elephants, you will select for differing rates of growth. Interesting that during hundred years of the seal hunt off the east coast of Canada, that now the seals are mating earlier, having their pups earlier, which are also being juveniles shorter. That's power of selection pressures. Also since we have no physicical evidence of how long these events took in dinosaurs, then your argument holds no value.
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Richard> But you did not answer my question about the content of the earth's air 200 million years ago. Why not?
Ramin > I only believe this: The pressure of earth's atmosphere at dinosaurs' age was more than other periods. I guess this is because of being more CO2 in atmosphere at that time.
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Richard> This completely ignores natural selection as a driving force. You would have to show that these morphological changes would have a selective advantage due to the environment you propose, up and beyond other selection pressures. What you say MIGHT be the case for some, but you would have to provide specific evidence that that is the case. With natural selection that is very difficult because of other
pressures.
Interesting a new dino was found, an older ceritopian, but was only
the size of a large dog. That means, that from the time of that
organism, pegged at some 150 myo, to the time of the larger
ceritopians, the earth's gravity was INCREASING, and had
significantly increased. So how is it that natural selection
favoured a larger increase in dino size over time when the earth's
gravity had been going up, according to your model? Why was this
ceritopian small to begin with at a time when you claim gravity was
small?
Ramin>The increase of gravity causes getting small body of animals in a class. But animals make there hearts stronger against increasing of gravity, and can make large their bodies again (of course in one higher class), and this action repeats alternatively. Consequently, new animal classes come to existence. No only dinosaurs but mammals and all other animal classes has started from small bodies in the beginning and then has got large. The reason for this, has been explained in article No (11)
http://www.oocities.org/ramin1102000/chap3-3page.html
At places which there is no air, ear can't hear any voice. At a place which air is thin, ear must be strong to hear voices properly. At a place which air is thick, an weak ear with simple structure can hear voices properly too. Past living reptiles' ear structure was so simple. So, it is clear that earth's atmosphere, was thick at that time. But after getting thin of air (it's pressure has been small) and animals had to made their ear's structure more complex (stronger) for hearing voices.
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Richard> Sorry, but this is absolutely not correct. The ear region of
reptiles was a primative state and is because reptiles spend much of
their time with their heads on the ground. The lower jaw picks up
sound vibrations from the ground, which is then transmitted to the
ear drum through the stapes. Once the cynodonts moved to an upright
stance, this did not work any longer and selection favoured
vibrations from air instead of the ground. Thus there was a
migration of the bones from the synapsid (reptilian) condition to the
mammalian condition, which required a change in articulation between
the jaw and skull going from synapsid condition to the mammalian
condition. There exists a very nice sequence of fossils that
documents this change. One fossil cynodont, probainognathus,
contains both the synapsid jaw joint and mammalian jaw joint
operating at the same time.
This is not only true for mammals, but for dinos and birds. It had
nothing to do with air pressure. You have to provide independant
physical evidence for higher pressure in the past (How high was the
pressure before 200myo?), and that I think will be near impossible to
do.
Whales have the same ear mechanism as us but have the highest density
for sound propogation, water. There is no correlation between ear
apparatus and sound medium density.
Also, the Linnean system of Class, Order, etc, is going to disappear
to be replaced by cladistic classfication. The rank of "class" will
not apply much longer. In fact, I have a roll in making that change
happen
Ramin> Because of being small quantity in the past, reptiles could stand up and take their heads straight (up), laters, under influence of getting gravity larged they forced to stich.
Mammals and birds have strong and complex ears but dinos were a reptile and had simple ear.
Whales have been evolutioned on land, and then have got marine. All of animals which have been evolutioned in water from the beginings, had simple ears.
Do you mean that your ears hear voices in vacuum too?
A thing which exists in nature, really exists. By changing classification agreement by human, there will be no change in nature.
Another reason for having a high pressure of air in the past (air high density), is flying power of giant reptiles.
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