Dinosaur Digestive Tracts Were Biochemical Marvels

Dinosaur Digestive Tracts Were Biochemical Marvels

www.foxnews.com
(visit the link for the full news article)


Related News Links:
www.foxnews.com
www.foxnews.com

Scientists used microbes usually found in the sheep rumen to simulate dino stomach and digest plant material such as ferns, ginkoes and conifers, plants previously thought to be too low in energy to sustain large dinos. These were plants present in the early dino era. These plants are not eaten much by present day lizzards.

My experience with lizzard diets is that they are opportunists with taste preferences. Iguannas, for instance, will graze the landscape prefering the youngest, tenderest leaves of prefered plants. In the early dino period less desirable plant species were present so that is what they ate and apparently flourished on, but later the choice and diversity of plants improved to the apparent benifit of dinosaurs.

www.foxnews.com
(visit the link for the full news article)

well they had to have something going for them to get so large, and many of the largest on a strictly herbivorous diet. seems a bit odd how they where so large then.... maby this is the answer to mans quest.......bigger isnt always better

Was.. was there perhaps less gravity ages ago, allowing larger life forms?

reply to post by depth om

---

Hi depth,

What was different? As I recall, in general the earth was flatter, lower, more swamplike, probably a bit smaller but gravity was probably not significantly different. Plantlife was more simple with more basic species. What those dinos had was some incredible genetics permitting physical adaptations allowing for their features. What we examine is just the mineralized remains of the biological structure. They may not have had skeletal material quite like the lizzard or the elephant. Some dinos for instance had much lighter skeletons than expected thus lightening and strengthening their frames.

thats why many scientist believe that birds are directly related to some dinosaurs but having lighter bones wouldn't be the problem it would be there legs and spines being able to hold all that mass up. gravity would be almost the sam as it was back then b/c the earth hasn't gained or lost any significant amount of mass.

reply to post by engenerQ

---

As any architect can tell you, the right structures can create some interesting buildings that appear to "defy gravity" - and many can do so while still using lightweight construction materials.

Dinosaur skeletons are quite well-adapted to the stresses they would have been under. In fact, to continue the architecture analogy, the main question about dino physiology isn't the framework, but the plumbing and electricity. Can you imagine the amount of power a sauropod heart would need in order for blood to travel all that distance?

reply to post by engenerQ

---

Hi eng,

I agree, but we do not know the structure that existed in dino bones. What adaptations they had to support mass is lost to us. All we see is the mineral deposit around the original structure. We do get clues like I mentioned in the light bone structure of some.

Dinos seem to have to arrived with amazing genetics and structure well adapted to the environment of their time. Prove me wrong!

i say magic


but the blood to extremity problem is quite the interesting problem to solve.

reply to post by engenerQ

---

Hi eng,

I did some more studying on the circulation problem. Giraffes solve their circulatory problem by having a very strong (4 chambered like all mammals) heart.

Modern lizzards cannot have long necks because their 3 chambered heart cannot provide the blood pressure necessary so they remain horizontal mostly.

Dinosaurs, however, had the 3 chambered heart but often had extremely long necks so they must have had very strong hearts. Did they have other adaptations to facilitate the long necks? I wonder if they didn't have pulsating arteries to assist the heart or valves in the arteries to stop backflow? And we just haven't found evidence yet in the fossil record.

The tendancy is for animals to get smaller with shorter necks when you look at the last 500 million years. Some have wondered if the earth is developing a stronger gravitic pull and animals need to adapt down in length and size?

Here is a discussion on circulatory adaptation of various species including dinosaurs. The author poses similar questions.

reply to post by plumranch

---

I remember it being said their size had something to do with having lungs better able to get more oxygen as they came from creatures that adapted to a time when earth's oxygen levels were low.
So when oxygen levels raised again bingo you had larger animals because they were able to oxygenate more blood thusly larger creatures.


[edit on 12-2-2008 by WraothAscendant]

reply to post by WraothAscendant

---

Hi Wraoth,

Generally I agree. The question to me is why are animals tending smaller post K/T event (last 65 million yrs)? I assume oxygen levels are rising gradually and have been but animals are tending smaller eg. no mammmoths and our lizzards are quite small. See the article quoted in my last post. The largest reptiles today are alligators and crocadiles.

Oxygen Levels on Earth Rose Gradually discusses the gradual rise of O2 levels beginning as early as 2.4 B yrs ago.

reply to post by plumranch

---

I am sure it was as anything a interesting mix of contributing factors that by themselves wouldn't have produced the sizes we have seen in that time period.

And I am also sure the arrival of mankind has stunted it too.

reply to post by WraothAscendant

---

He Wraoth,

I agree.

I'll add a list of questions to ponder:

Why did the birds or birdlike creatures survive the 65 M yrs ago extictions that apparently wiped out all the large dinos?

Why did the predomenant land animal then swing to the mammals? And also, what turned the evolution of reptiles to smaller less dominant types?

Why don't we see and abundance of the transitional species forms that would be expected in evolutionary processes?

reply to post by plumranch

---

Well I think it was another combination of factors that killed the dinosaurs.
Just like what helped them to dominance.
I remember the thought that small mammals were starting to make life harder for the dinosaurs amongst other things.
Of course the final nail would have to be the KT event.
I tend to reject the idea that one big event can bring about what we seen happening then. But a bunch of smaller and maybe one or two big ones factors will knock something out.



KT event seems like it would help abundantly.
I know there is conjecture on this but I for one accept some of the KT events implications.



Don't take this wrong please. But you do know how against the odds it is we have what fossils we do have right?
Fossilization takes a set of specific conditions to happen.
Otherwise. No fossils.

reply to post by WraothAscendant

---

I wanted to mention this thread Mass extinctions: The microbes strike back. This study found that 4 out of 5 major extinctions were due mostly to an overgrowth of H2S forming bacteria essentially killing off everything. The K/T event was unique. And microbes may have been involved in KT also. Generally it went: earth heated up, oceans stagnated, H2S microbes overgrew, oceans and atmospheres became poisonous and acidic causing extinctions. There were at least 5 known extinction events!



To me it seems as likely that the large lizzard spp would return after KT as they could have free reign.


You're right. And I can argue that it wasn't simple evolutionary processes that were bringing about various spp. but you really can't prove either way, ie. there may be no solid proof of evolution but then again there is no obvious proof against it.

reply to post by plumranch

---

Yeppers we can argue it either way and still not be able to definitively "win" it.
I am willing to agree to disagree.

As for the large lizards taking over you gotta remember they weren't exactly lizards they were more like birds. Even the inside of T-Rex's bones are like a ostrich.
I think the smaller more able to hide mammals had the advantage post KT.

Oh and the KT event was an asteroid impact near what is now the Yucatan.

Imma dinosaur nut and have been for a long time.

Reply to Wroathascendant:

When scientists argue for evolution they are unable to demonstrate the incrementalism of the process from one species to the other anywhere in the larger species so they bring up the microorganism. They show us how this species of bacteria morphed into this new species with different characteristics.

I have no argument with the bacteria, they do that sort of thing. But does it happen with larger species? It must happen, right? Ok, where is the unquestionable example! Evolution usually wins by default. All those intermediate individuals must be there somewhere, we just don't see them in the fossil or any other record!

reply to post by plumranch

---

There are some and I tend to believe in a "guided" evolution.
But I think I see the hostility getting ready to rear its ugly head so shall we drop it?

reply to post by plumranch

---

To answer the post before this one, there were in fact, lizards with long necks. Tanystropheus was an aquatic lizard that had a very long neck - I forget just HOW long, but long enough.

Odds are that our depictions of sauropods and plesiosaurs as having curvy, sinuous necks are pretty inaccurate. The sheer weight of them would have necessitated a horizontal posture. There have been some sauropods found with flattened snouts lined with close-packed teeth. Basically htey were vegetation vacuums, trundling along and just eating a path through the low-growing plants.

Plesiosaurs certainly could not have lifted their necks as they are depicted as doing. Like tanystropheus, they have almost no muscle connections on their bones. Odds are, they swam along, sticking hteir heads into schools of fish, or floated at the surface and snapped up fish that swam in the shade beneath them.

As to the pumping power of the dinosaur heart... they had a four-chambered heart just like birds and mammals. How do we know? Beleive it or not, we've found a fossilized dinosaur heart!