The Paleontology Thread

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Paleontology

Postby Apollonius » Thu Jan 31, 2013 7:49 pm

There was a paleontology thread on the old forum.


This seems like a good starting point for one here:



Survival of the prettiest: Sexual selection can be inferred from the fossil record - ScienceDaily, 29 January 2013
http://www.sciencedaily.com/releases/20 ... 080217.htm


Jan. 29, 2013 — Detecting sexual selection in the fossil record is not impossible, according to scientists writing in Trends in Ecology and Evolution this month, co-authored by Dr Darren Naish of the University of Southampton.

The term "sexual selection" refers to the evolutionary pressures that relate to a species' ability to repel rivals, meet mates and pass on genes. We can observe these processes happening in living animals but how do palaeontologists know that sexual selection operated in fossil ones?

Historically, palaeontologists have thought it challenging, even impossible, to recognise sexual selection in extinct animals. Many fossil animals have elaborate crests, horns, frills and other structures that look like they were used in sexual display but it can be difficult to distinguish these structures from those that might play a role in feeding behaviour, escaping predators, controlling body temperature and so on.

However in their review, the scientists argue that clues in the fossil record can indeed be used to infer sexual selection. ...
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Re: Paleontology

Postby Miss_Faucie_Fishtits » Thu Jan 31, 2013 8:10 pm

Too bad the fossil record does not preserve aspects of social media. Then we would have more than scant clues.....'>>.........
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Re: Paleontology

Postby Azrael » Fri Feb 01, 2013 12:17 am

Apollonius wrote:There was a paleontology thread on the old forum.


This seems like a good starting point for one here:



Survival of the prettiest: Sexual selection can be inferred from the fossil record - ScienceDaily, 29 January 2013
http://www.sciencedaily.com/releases/20 ... 080217.htm

Very interesting subject. Thanks.

From the linked article in Science Daily.

Image

Sexual dimorphism can indicate that the trait is related to sexual selection.

Image

Goldie's Bird of Paradise
cultivate a white rose
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Re: Paleontology

Postby Endovelico » Fri Feb 08, 2013 11:00 am

Image

Our earliest forefather, which lived about 200,000 years after the demise of dinosaurs.

http://www.bbc.co.uk/news/science-environment-21350900
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Re: Paleontology

Postby Apollonius » Fri Feb 08, 2013 4:18 pm

Dinosaur extinction: Scientists estimate 'most accurate' date - BBC News, 8 February 2013
http://www.bbc.co.uk/news/uk-scotland-g ... t-21379024


Scientists believe they have determined the most precise date yet for the extinction of dinosaurs.

Researchers from Glasgow University were part of an international team that has been investigating the demise of the dinosaur.

By using dating techniques on rock and ash samples, they established the creatures died out about 66,038,000 years ago - give or take 11,000 years.

That date appears to coincide with the impact of a comet or asteroid.

Debate has raged as to whether the giant impact was the sole cause of a quick demise of the dinosaurs, whether they were already in decline at the time of the impact, or whether the impact in fact happened as much as 300,000 years after they were gone.

The study has been published in the journal Science, and also involved researchers from the Berkeley Geochronology Center and University of California, Berkeley in the US and Vrije University Amsterdam in the Netherlands. ...
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Re: Paleontology

Postby Apollonius » Fri Feb 08, 2013 5:40 pm

More news from 66,038,000 years ago:



Old fossils solve mystery of earliest bird extinction
- Leila Battison, BBC News, 20 September 2011
http://www.bbc.co.uk/news/science-environment-14979905


Many early bird species suffered from the same catastrophic extinction as the dinosaurs, new research has shown.

The meteorite impact that coincided with the disappearance of the dinosaurs 65 million years ago, also saw a rapid decline in primitive bird species.

Only a few bird groups survived through the mass extinction, from which all modern birds are descended.

Researchers at Yale University have published their findings in PNAS this week.

There has been a long standing debate over the fate of the earliest "archaic" birds, which first evolved around 200 million years ago.

Whether their populations declined slowly towards the end of the Cretaceous period, or whether they suffered a sudden mass extinction at the Cretaceous-Tertiary (K-T) boundary is unresolved, owing to conflicting evidence.

DNA studies have attempted to date the origin of modern birds; some suggest that they appeared before the extinction of dinosaurs, with large numbers of them surviving through the extinction event.

But the molecular clock suffers from "method issues", explains Dr Longrich of Yale University, and well-dated fossils are needed for "stratigraphic constraint" of the extinctions.

There are problems with the fossil record however. It is incomplete, owing to the extreme rarity of bird fossils.

Bird bones are very difficult to preserve as fossils as they are small and light, and easily damaged or swept away in rivers.

But the new research, headed by Dr Longrich, has made use of fragmentary bird fossils collected up to 100 years ago, from locations across North America.

New diversity
The fossil deposits, in North and South Dakota and Wyoming in the US, and Saskatchewan in Canada, date from the last 1.5 million years of the Cretaceous period.

More precise dating places the bird fossils to within 300,000 years of the extinction event - a very short period on geological timescales.

These fossils had been studied before, but they have been "shoehorned" into modern groups on the basis of their overall similarity.

Dr Longrich and his team have reanalysed and reclassified these important fossil fragments, using features of the shoulder joint to assign the fossils to modern and ancient groups.

The shoulder bone, or "coracoid" is used for classification because it is the most common bone fragment preserved, and it doesn't vary much between individuals of the same species.

Analysing 24 specimens, the researchers identified 17 species, seven of which were "archaic birds" that are not seen after the K-T mass extinction.

These findings show for the first time a diversity of archaic birds alive, right up until the end of the Cretaceous.

This would mean that the archaic birds went extinct abruptly 65 million years ago, and that modern birds must have descended from just a few groups that survived the event. ...
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Jumping the Placental Ancestor

Postby Yukon Cornelius » Sat Feb 09, 2013 5:04 am

Endovelico wrote:Image

Our earliest forefather, which lived about 200,000 years after the demise of dinosaurs.

http://www.bbc.co.uk/news/science-environment-21350900

Listed as a "hypothetical placental ancestor" in the article.
http://www.stonybrook.edu/sb/images/fea ... 130208.pdf

Articles like this are simply unbelievable: now "hypothetical placental ancestor" is "science."

At least Nebraska Man has a pig's tooth to go on. Absolutely unbelievable.
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Re: Jumping the Placental Ancestor

Postby Endovelico » Sat Feb 09, 2013 1:06 pm

Yukon Cornelius wrote:
Endovelico wrote:Image

Our earliest forefather, which lived about 200,000 years after the demise of dinosaurs.

http://www.bbc.co.uk/news/science-environment-21350900

Listed as a "hypothetical placental ancestor" in the article.
http://www.stonybrook.edu/sb/images/fea ... 130208.pdf

Articles like this are simply unbelievable: now "hypothetical placental ancestor" is "science."

At least Nebraska Man has a pig's tooth to go on. Absolutely unbelievable.


Why is it unbelievable? I'm not saying we must believe it, but why is it unbelievable?...
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Re: Paleontology

Postby noddy » Mon Feb 11, 2013 2:43 am

while i have no doubt some folk take this kind of theoretical science as fact its wrong to compare this kind of thing to biblical stories.

to me its nothing more than a thought experiment and a rough indicator of where our knowledge is at the present moment, nothing more, nothing less.

then again, id say the same about biblical stories too.
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Re: Paleontology

Postby Apollonius » Thu Mar 07, 2013 1:36 am

Giant camel fossil found in Arctic - Rebecca Morelle, BBC News, 5 March 2013
http://www.bbc.co.uk/news/science-environment-21673940




Camels are well known for their ability to survive the hot and dry conditions of the desert, but a study suggests they once thrived in colder climes.

Scientists have unearthed the fossilised remains of a giant species of camel in Canada's High Arctic.

An analysis of protein found in the bones has revealed that this creature, which lived about 3.5 million years ago, is an ancestor of today's species.

The research is published in the journal Nature Communications.

Dr Mike Buckley, an author of the paper from the University of Manchester, said: "What's interesting about this story is the location: this is the northernmost evidence of camels."

Cold conditions

The mid-Pliocene Epoch was a warm period[Apollonius advises: actually, not warm, but warmer than the Pleistocene and the Early Anthropocene] of the Earth's history - but surviving in the Arctic would have still been tough.

The ancient camels would have had to cope with long and harsh winters, with temperatures plunging well below freezing. There would have been snow storms and months of perpetual darkness. ...
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Re: Paleontology

Postby Apollonius » Fri Nov 01, 2013 6:54 pm


Dinosaur titans: Sauropods' secrets revealed
- Victoria Gill, BBC News, 30 October 2013
http://www.bbc.co.uk/news/science-environment-24659003



In an era of giants, sauropods dwarfed everything.

These dinoasurs, including the diplodocus, were the biggest to walk the Earth. T. rex would have nipped at the knees of the largest sauropod - Argentinosaurus huinculensis.

University of Manchester researchers have now made a digital Argentinosaurus robot to work out how this 80-tonne monster would have moved its vast bulk.

The study is published in an issue of PLoS One on "sauropod gigantism".

The immense size of sauropods - the long-necked, tree-trunk-legged storybook giants of the Jurassic period - presents a quandary for biologists because they push animal bones and muscles to their limit.

This is why researchers have set out to answer some of the big questions about these very big animals, including: How did their muscles and bones support and move their bodies? How did their digestive system process sufficient food? And how high could they have reached with their immensely long necks (much longer, proportionally, than a giraffe's)?
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Re: Paleontology

Postby Endovelico » Thu Dec 05, 2013 11:43 am

Sima de los Huesos: Scientists Sequence Genome of Enigmatic Hominin
Dec 4, 2013 by Sci-News.com

Researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, have sequenced the mitochondrial genome of a 400,000-year-old hominin found in Sima de los Huesos, Spain.

Sima de los Huesos – the Pit of Bones – is a cave site in Atapuerca Mountains, northern Spain.

During 1990s, at least 28 skeletons of Middle Pleistocene hominins were found at the site by Spanish paleontologists led by Dr Juan-Luis Arsuaga from the Center for Research on Human Evolution and Behaviour.

The scientists dated the finds as being 600,000 to 300,000 years old, and assigned them as belonging to Homo heidelbergensis.

In 2010s, Dr Arsuaga teamed up with Max Planck scientists, who recently developed novel techniques for retrieving and sequencing highly degraded ancient DNA.

The team applied the new techniques to hominin remains from the Sima de los Huesos site to sequence their mitochondrial DNA (mtDNA) and then compared the genome with that of Neandertals, Denisovans, present-day humans, and apes.

The results show that the Sima de los Huesos hominin lived about 400,000 years ago and shared a common ancestor with Denisovans, an ancient human species that lived in a vast range from Siberia to Southeast Asia at the same time as Neanderthals, about 700,000 years ago.

“The fact that the mtDNA of the Sima de los Huesos hominin shares a common ancestor with Denisovan rather than Neanderthal mtDNAs is unexpected since its skeletal remains carry Neanderthal-derived features,” said Dr Matthias Meyer, the lead author of a paper published online in Nature.

“Considering their age and Neanderthal-like features, the Sima de los Huesos hominins were likely related to the population ancestral to both Neanderthals and Denisovans. Another possibility is that gene flow from yet another group of hominins brought the Denisova-like mtDNA into the Sima de los Huesos hominins or their ancestors.”

Study co-author Dr Svante Pääbo added: “our results show that we can now study DNA from human ancestors that are hundreds of thousands of years old. This opens prospects to study the genes of the ancestors of Neanderthals and Denisovans. It is tremendously exciting.”

“This unexpected result points to a complex pattern of evolution in the origin of Neanderthals and modern humans. I hope that more research will help clarify the genetic relationships of the hominins from Sima de los Huesos to Neandertals and Denisovans,” Dr Arsuaga said.

http://www.sci-news.com/othersciences/anthropology/science-sima-de-los-huesos-hominins-genome-01596.html


Sequencing genomes 400,000 years old is extraordinary. We will be able to find out a lot about our ancestry, in this manner. I wonder how far back we will be able to go.
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Re: Paleontology

Postby Miss_Faucie_Fishtits » Mon Jan 27, 2014 12:19 am

Related.......

A 7,000-year-old man whose bones were left behind in a Spanish cave had the dark skin of an African, but the blue eyes of a Scandinavian. He was a hunter-gatherer who ate a low-starch diet and couldn't digest milk well — which meshes with the lifestyle that predated the rise of agriculture. But his immune system was already starting to adapt to a new lifestyle.


Image

http://www.nbcnews.com/science/dark-ski ... snhp&pos=1
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Re: Paleontology

Postby Endovelico » Mon Jan 27, 2014 10:13 am

Since the Iberian Peninsula was populated before Scandinavia, maybe we should say that Scandinavians have the blue eyes of a Spaniard... :P
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Paleontology

Postby Zack Morris » Fri Sep 12, 2014 4:59 am

A fascinating study of perhaps the most enigmatic dinosaur, Spinosaurus, was recently made possible thanks to the discovery of new material from Morocco. The original Spinosaurus aegyptiacus specimen was discovered in Egypt in 1912 but was destroyed by Allied bombing during World War II. It wasn't until the last couple of decades that new material was found to piece together a more complete picture of this strange and wonderful creature. When I was growing up, Spinosaurus was a phantom known only from the descriptions Ernst Stromer left behind, and was often depicted incorrectly in children's books as a typical upright theropod save for the sail on its back.

The New York Times has a wonderful write up of the serendipitous encounter with a Moroccan nomad that led to the discovery of the most recent Spinosaurus remains:

A Lost-and-Found Nomad Helps Solve the Mystery of a Swimming Dinosaur

Image

Image

This is the first example of a dinosaur adapted for a primarily aquatic lifestyle and a fascinating example of convergent evolution. Spinosaurus's skull, like that of its relatives Baryonyx and Suchomimus, is strikingly crocodilian, right down to the small network of sinuses at the tip of the snout that in crocodiles serve as pressure sensors to track movement of nearby prey in water.

The staggering diversity of dinosaur body forms continues to astound.
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Re: The Paleontology Thread

Postby Zack Morris » Fri Sep 12, 2014 5:21 am

I decided to start this thread because for some reason, my latent interest in paleontology (which when I was young lasted much longer than the usual "dinosaur phase" boys go through) has been rekindled in the last year. Living 5 blocks from the American Museum of Natural History has certainly helped ;) Surprisingly, there are some good fossil sites out here on the densely populated East Coast. A month ago, I visited a Devonian quarry in upstate New York known for abundant trilobite and brachiopod fossils and last weekend, I made a trip out to Big Brook in New Jersey. This site is known for late Cretaceous (66-75 million years old) marine fossils, primarily shark teeth, belemnites, shellfish, and if one is extremely fortunate, mosasaur teeth.

Big Brook
river.jpg
Big Brook
river.jpg (151.01 KiB) Viewed 623 times


Can you spot the shark tooth?
filter.jpg
Spot the tooth
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My finds: shark teeth, a shell, and a belemnite.
all_teeth.jpg
Finds
all_teeth.jpg (96.66 KiB) Viewed 623 times


Summer is over for this year but next year I'm planning to go hunting for the real deal in the mountain states: dinosaurs.
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Re: The Paleontology Thread

Postby Apollonius » Fri Sep 12, 2014 4:53 pm

These posts belong here:

viewtopic.php?f=4&t=1675




Hello Zack,


As I explained on the old board:


Always loved the subject of natural history, maybe as much as or even more than human history.


For my sixth birthday my parents gave me a book that I had nagged them about the whole previous year. This was originally serialized in Life Magazine:



WorldWeLiveIn-Life,Dec.8,1952.jpg
WorldWeLiveIn-Life,Dec.8,1952.jpg (16.68 KiB) Viewed 609 times






Have always been impressed that even 60 years ago it was appreciated that the moon was once much closer to earth than it is now.


According to John Barrow, author of The Artful Universe (Clarendon House, 1995) the moon will only create a total eclipse of the sun for another 500 million years, after which time it will have receded too far away to completely obscure it. I wonder what it would have done for the study of astronomy had humans appeared later (or earlier).
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Re: The Paleontology Thread

Postby Apollonius » Fri Sep 12, 2014 4:55 pm

Another recent find:


'Dreadnought' dinosaur yields big bone haul - Jonathan Amos, BBC News, 4 September 2014
http://www.bbc.com/news/science-environment-29050114


New fossils found in Argentina represent the most complete giant sauropod dinosaur ever discovered.


Scientists say they have 70% of the key bones needed to fully describe the creature, Dreadnoughtus schrani.

It means they can confidently estimate its great bulk - a beast that measured 26m from head to tail and weighed in at almost 60 tonnes.

Remarkably, the skeletal analysis reveals Dreadnoughtus was still growing at the time of its death.

Quite how large the dino might have become, no-one can say.

The Patagonian rocks from which it was pulled suggest that the young animal's life was cut short in a catastrophic flood.

A detailed write-up on the 77-million-year-old fossils appears in the journal Scientific Reports.

These immense, long-necked, plant-eating dinos were the most massive beasts ever to plod the Earth's land surface.

Ken Lacovara: "Previous skeletons have been so fragmentary"

Some, such as Argentinosaurus - a previous South American discovery - could even have topped the scales at close to 100 tonnes.

But such estimates are based on very fragmentary evidence. In the case of Argentinosaurus, this is just half-a-dozen vertebrae in its mid-back, a few hip pieces and a shin bone.

And this is why Dreadnoughtus is generating so much excitement.

Although its skull has not survived, almost half of the rest of the skeleton has been preserved.

And when you consider just the key bone groups, more than two-thirds of the complete animal is present in fossil form. ...
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Re: The Paleontology Thread

Postby Apollonius » Fri Sep 12, 2014 5:01 pm

Over the last few days I have been reading and re-reading a book which is bound to be the standard reference work on the subject for some years, called The Great Extinctions by Norman MacLeod.


From the back cover:

For over a century, geologists have tried to identify and understand the processes responsible for the complex history of species extinction. This search as become even more important over the last decade as human populations and human technology may now rival sea-level change, volcanic eruptions and asteroid impacts as an extinction mechnaism.




The most famous mass extinction event was when the dinosaurs died out, but there have been at least four other mass extinctions and this book gives some attention to all of these. It's full of beautifully presented maps, graphs, and illustrations which definitely add to its appeal and explanatory power. I also appreciate the author's dedication to presenting the data fairly, in effect letting it speak for itself, rather than appealing to any one theory.



For example, the chapter on the End-Cretaceous extinctions concludes:


Let me close this discussion by stating there is no question that at least one (possibly more) large impact(s) occurred during latest Maastrichtian time. There is also no question that this (these) impacts would have been devastating for local biotas and may have had short-term (less than 100 years) environmental consequences for the planet. But advocating bolide impact as the only credible cause for the end-Cretaceous extinctions is far too much of an oversimplification for myself and many of my palaelontological colleagues to accept, especially insofar as the mechanisms associated with bolide impact do such a poor job explaining the patterns we see in our palaeontological and geological data [see Archibald, 2010, a letter co-authored by 28 palaeontologists from across the palaeontological subdisciplines outlining opposition to the K-Pg impact-extinction scenario and written in response to an article published by Schulte 2010 supporting this model, but coauthored by only 12 palaeontologists the overwhelming majority of whom were microfossil specialists]. Based on a consideration of all the evidence presented above I find the causal framework that accounts for the greatest proportion of evidence is one that acknowledges the totality of physical events that are known to have occurred at the end of the Cretaceous: a scenario that invokes sea-level change, Deccan volcanism and the Chicxulub impact as all playing roles in precipitating the end-Cretaceous extinction event with terrestrial extinction deriving primarily from habitat fragmentation resulting from the end-Maastrichtian sea-level regression and marine extinctions driven primarily by short-term collapse in primary productivity.

-- Norman MacLeod, The Great Extinctions: What Causes Them & How They Shape Life (Firefly Books, 2013)





There are lots of special features about this book. If you learned your names for geological time periods some years ago, this book will provide you with an update. As our knowledge has increased, most periods have been subdivided. For example, the Cretaceous period now includes no fewer than 12 subdivisions, of which the Maastrichtian is the last. It latest from 72.1 to 66 million years ago.




The author is Keeper of Paleontology at the Natural History Museum London. I like his attitude. In the introduction he writes:


It has been said that the secret to a long life is to have a chronic incurable disease and to keep treating it. By the same token, the secret to a productive life in science is to have a chronic insoluble problem and to keep working on it.
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Re: The Paleontology Thread

Postby Zack Morris » Sat Sep 13, 2014 1:34 am

Apollonius wrote:These posts belong here:

viewtopic.php?f=4&t=1675


Ah, didn't notice this thread, sorry. Thanks! This one should definitely be moved there.

According to John Barrow, author of The Artful Universe (Clarendon House, 1995) the moon will only create a total eclipse of the sun for another 50 million years, after which time it will have receded to far away to totally obscure it. I wonder what it would have done for the study of astronomy had humans appeared later (or earlier).


I wonder what effect this will have on the tides and, consequently, on life? I know that the moon has been closer but has it been considerably farther away at any point in the last 500 million years?
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Re: The Paleontology Thread

Postby Zack Morris » Sat Sep 13, 2014 1:53 am

Apollonius wrote:The most famous mass extinction event was when the dinosaurs died out, but there have been at least four other mass extinctions and this book gives some attention to all of these. It's full of beautifully presented maps, graphs, and illustrations which definitely add to its appeal and explanatory power. I also appreciate the author's dedication to presenting the data fairly, in effect letting it speak for itself, rather than appealing to any one theory.


The Permian/Triassic extinction event was the largest in terms of proportion of life eliminated. Given that there is no evidence of bolides playing any role, we are left to contemplate the frightening possibility that the Earth may one day once again produce such an extinction. Some would argue that the process is already well underway due to human disruption of the biosphere.

But advocating bolide impact as the only credible cause for the end-Cretaceous extinctions is far too much of an oversimplification for myself and many of my palaelontological colleagues to accept, especially insofar as the mechanisms associated with bolide impact do such a poor job explaining the patterns we see in our palaeontological and geological data [see Archibald, 2010, a letter co-authored by 28 palaeontologists from across the palaeontological subdisciplines outlining opposition to the K-Pg impact-extinction scenario and written in response to an article published by Schulte 2010 supporting this model, but coauthored by only 12 palaeontologists the overwhelming majority of whom were microfossil specialists]. Based on a consideration of all the evidence presented above I find the causal framework that accounts for the greatest proportion of evidence is one that acknowledges the totality of physical events that are known to have occurred at the end of the Cretaceous: a scenario that invokes sea-level change, Deccan volcanism and the Chicxulub impact as all playing roles in precipitating the end-Cretaceous extinction event with terrestrial extinction deriving primarily from habitat fragmentation resulting from the end-Maastrichtian sea-level regression and marine extinctions driven primarily by short-term collapse in primary productivity.


It has long been argued that dinosaur biodiversity was on the decline in the late Cretaceous and an unfortunate convergence of events finished them off. If I'm not mistaken, marine reptile diversity peaked in the late Jurassic, with ichthyosaurs disappearing 93 mya in what is thought to have been a climate-related extinction event.

There are lots of special features about this book. If you learned your names for geological time periods, this book will provide you with an update. As our knowledge has increased, most periods have been subdivided. For example, the Cretaceous period now includes no fewer than 12 subdivisions, of which the Maastrichtian is the last. It latest from 72.1 to 66 million years ago.


These are called epochs and have been around for a long time, certainly more than 40 years, and perhaps back to the original geological chronologies of the 19th century. The term Maastrichtian was introduced in 1849, according to Wikipedia. Unlike the Paleozoic and Mesozoic, our Cenozoic era is commonly referenced in terms of its epochs rather than periods:

Image

You may also recall hearing the common terms Pennsylvanian and Mississippian, which are actually sub-periods (a level of classification smaller than a period but greater than an epoch) of the Carboniferous period.
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Re: The Paleontology Thread

Postby Apollonius » Sat Sep 13, 2014 2:57 am

Eclipses occur because of an accident of Nature. The true diameter of the Sun is about 400 times greater than that of the Moon; its' distance from Earth is also about 400 times greater than that of the Moon. These gross disparities conspire to make the apparent sizes of the Sun and the Moon on the sky the same. As a result, the passage of the Moon in front of the Sun can cover the face of the Sun completely, to produce a total eclipse of the Sun. By way of contrast, if we examine the other planets in the solar system, we find that their moons will appear much larger than the Sun in their skies. On the average, our Moon appears to be just a little smaller than the Sun when viewed from the Earth. But the difference is small enough to be overcome by the variations in the distance between the Earth and the Moon, so that there are also periods when the face of the Moon is slightly larger than that of the Sun. The situation is finely balanced: if the distance to the Moon were increased by a mere 8 per cent (about 18,000 miles) then total eclipses of the Sun would never been seen from the Earth. Now, we have already explained that the distance between the Earth and the Moon is gradually increasing by a few centimetres every year. Five hundred million years from now, the Moon will be so far away that total eclipses of the Sun will be no more.





Likewise interesting:

 

The length of the day is in fact very slowly lengthening, by about two-thousandth of a second every century, because of the pull of the Moon. Over the vast periods of time required for significant geological or biological change this small change becomes quite significant. The day would have been eleven hours shorter two thousand million years ago when the oldest known fossilized bacteria were alive. [Apollonius notes that older specimens have been discovered since this was written] Direct evidence of this change imprinting itself upon living things has been found in some coral reefs in the Bahamas. Daily and annual growth bands (rather like tree rings) are laid down in the coral, and by counting how many daily bands are in each annual band one can determine how many daily cycles there were in a year. Contemporary coral growths display about 365 bands for each year, roughly as expected, while 350 million-year-old corals, near by, display about 400 daily rings in each annual band, indicating that the day was then only about 21.9 hours long. This is almost exactly the value that we would expect at that time in the past, given the rate at which the Moon's pull is changing. If we extrapolate back to the formation of the Earth, then the young Earth might have had days lasting only about six hours. Thus, if the Moon did not exist, our day would probably be only a quarter of its present length. This would have consequences for the Earth's magnetic field as well. With a day of only six hours, the more rapid rotation of charged particles within the Earth would produce a terrestrial field about three times stronger than at present. Magnetic sensing would be a more cost-effective adaptation for living things on such a world. But the most far-reaching environmental effects of a shorter day would follow from the far stronger winds that would whip across the planet's rotating surface. The extent of erosion by wind and waves would be very great. There would be selective pressure towards smaller trees, and for plants to grow smaller, stronger leaves that were less susceptible to removal. This might well alter the course of the evolution of Earth's atmosphere by delaying the early conversion of its carbon dioxide atmosphere into oxygen by the action of photosynthesis.

-- John D. Barrow, The Artful Universe (Clarendon Press, 1995)
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Re: The Paleontology Thread

Postby Doc » Sat Oct 04, 2014 4:43 pm

Apollonius wrote:
Eclipses occur because of an accident of Nature. The true diameter of the Sun is about 400 times greater than that of the Moon; its' distance from Earth is also about 400 times greater than that of the Moon. These gross disparities conspire to make the apparent sizes of the Sun and the Moon on the sky the same. As a result, the passage of the Moon in front of the Sun can cover the face of the Sun completely, to produce a total eclipse of the Sun. By way of contrast, if we examine the other planets in the solar system, we find that their moons will appear much larger than the Sun in their skies. On the average, our Moon appears to be just a little smaller than the Sun when viewed from the Earth. But the difference is small enough to be overcome by the variations in the distance between the Earth and the Moon, so that there are also periods when the face of the Moon is slightly larger than that of the Sun. The situation is finely balanced: if the distance to the Moon were increased by a mere 8 per cent (about 18,000 miles) then total eclipses of the Sun would never been seen from the Earth. Now, we have already explained that the distance between the Earth and the Moon is gradually increasing by a few centimetres every year. Five hundred million years from now, the Moon will be so far away that total eclipses of the Sun will be no more.





Likewise interesting:

 

The length of the day is in fact very slowly lengthening, by about two-thousandth of a second every century, because of the pull of the Moon. Over the vast periods of time required for significant geological or biological change this small change becomes quite significant. The day would have been eleven hours shorter two thousand million years ago when the oldest known fossilized bacteria were alive. [Apollonius notes that older specimens have been discovered since this was written] Direct evidence of this change imprinting itself upon living things has been found in some coral reefs in the Bahamas. Daily and annual growth bands (rather like tree rings) are laid down in the coral, and by counting how many daily bands are in each annual band one can determine how many daily cycles there were in a year. Contemporary coral growths display about 365 bands for each year, roughly as expected, while 350 million-year-old corals, near by, display about 400 daily rings in each annual band, indicating that the day was then only about 21.9 hours long. This is almost exactly the value that we would expect at that time in the past, given the rate at which the Moon's pull is changing. If we extrapolate back to the formation of the Earth, then the young Earth might have had days lasting only about six hours. Thus, if the Moon did not exist, our day would probably be only a quarter of its present length. This would have consequences for the Earth's magnetic field as well. With a day of only six hours, the more rapid rotation of charged particles within the Earth would produce a terrestrial field about three times stronger than at present. Magnetic sensing would be a more cost-effective adaptation for living things on such a world. But the most far-reaching environmental effects of a shorter day would follow from the far stronger winds that would whip across the planet's rotating surface. The extent of erosion by wind and waves would be very great. There would be selective pressure towards smaller trees, and for plants to grow smaller, stronger leaves that were less susceptible to removal. This might well alter the course of the evolution of Earth's atmosphere by delaying the early conversion of its carbon dioxide atmosphere into oxygen by the action of photosynthesis.

-- John D. Barrow, The Artful Universe (Clarendon Press, 1995)


WOW sounds like the basis for a new religion. "Man made Global Slowing" With all those wind mills out there slowing the planet by resisting the winds it is bound to happen. :lol:
The classes and the races to weak to master the new conditions of life must give way {..} They must perish in the revolutionary holocaust --Karl Marx
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Re: The Paleontology Thread

Postby Nonc Hilaire » Sat Oct 04, 2014 5:41 pm

Man Made Global slowing! Good one! :lol:
“Christ has no body now but yours. Yours are the eyes through which he looks with compassion on this world. Yours are the feet with which he walks among His people to do good. Yours are the hands through which he blesses His creation.”

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Re: The Paleontology Thread

Postby Doc » Sat Oct 04, 2014 7:52 pm

Nonc Hilaire wrote:Man Made Global slowing! Good one! :lol:



You shouldn't laugh, you Man Made Global Slowing denier !! Do you work for the big evil corporation that are raping the earth's spin for profits? There is a consensus on Global Slowing. Scientist all agree that the Earth's rotation is slowing by two seconds per year !!!(Also, I looked in the mirror and me and the guy in it absolutely agree). The Big evil wind energy corps are trying to silence those who object. They even make the bogus claim that if the earth's rotation did slow down to one day per year that Climate Change would completely stop !! Yet deny the fact that longer days mean more work hours per day. Which would mean more profits for them !!!


SO stop laughing and be serious People that laugh at MMGS should be put in jail !!! We have to stop Man Made Global Slowing NOW #&$&$&!!!!
The classes and the races to weak to master the new conditions of life must give way {..} They must perish in the revolutionary holocaust --Karl Marx
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