Prehistoric big cats, video


This 7 December 2018 video says about itself:

10 Amazing Big Cats From Prehistory Some Of Which You May Not Have Heard Of

Before human beings, Felidae, or cats, were the most successful, powerful predators in most of the world. Even today, big cats such as tigers, lions, jaguars and leopards keep causing admiration and fear, but these magnificent beasts are dwarfed by some of their extinct relatives.

Here are prehistory’s largest, mightiest cats, some of which were seen by humans only a few thousand years ago.

1- Giant Cheetah The Giant Cheetah (Acinonyx pardinensis), belonged to the same genus as modern day Cheetah (Acinonyx jubatus), and probably looked very similar, but it was much bigger.

2- Xenosmilus hodsonae Xenosmilus hodsonae is a relative to Smilodon (“saber-toothed tiger”), but instead of having long, blade-like fangs, it had shorter and thicker teeth.

3- Giant Jaguar In prehistoric times, both North and South America were home to gigantic jaguars, belonging to the same species as modern day jaguars (Panthera onca) but much bigger.

4- European Jaguar It was a huge predator, weighing up to 210 Kgs (463) or more, and probably at the top of the food chain in Europe, 1.5 million years ago. Its fossil remains have been found in Germany, France, England, Spain and the Netherlands.

5- Cave Lion The Cave lion was a gigantic subspecies of lion, weighing up to 300 kgs (661lbs) or more (and therefore, being as large as the Amur or Siberian tiger, the largest cat of our days.

6- Homotherium serum Also known as the “Scimitar cat”, Homotherium serum was one of the most successful felines in prehistoric times, being found in North and South America, Europe, Asia and Africa.

7- Machairodus aphanistus Machairodus aphanistus probably looked pretty much like a gigantic tiger with saber teeth; it had very tiger-like proportions and a long tail, although it is impossible to know if it had stripes, spots or any other kind of fur markings.

8- American Lion The American lion or Panthera atrox, is probably the best known of all prehistoric cats after Smilodon. It lived in both North and South America (from Alaska to Peru) during the Pleistocene epoch, and went extinct 11,000 years ago, at the end of the last Ice Age.

9- Pleistocene Tiger The most obscure cat in the list, being known from fragmentary remains which have yet to be formally described. Most likely “Pleistocene tiger” is not a separate species, but rather the “early version” of the same tigers we see today. It is also known as Ngandong tiger.

10- Smilodon Smilodon is one of the most famous prehistoric predators, and also one of the most formidable. There were at least three species living in both North and South America; the smallest species, Smilodon gracilis, was about the size of a modern day jaguar, while Smilodon fatalis was as big as a lion.

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Permian-Triassic mass extinction by global warming


This July 2018 video says about itself:

252 million years ago 96% of all marine species and 70% of terrestrial vertebrate species vanished, this was the Permian extinction.

From the University of Washington in the USA:

Biggest mass extinction caused by global warming leaving ocean animals gasping for breath

December 6, 2018

Summary: By combining ocean models, animal metabolism and fossil records, researchers show that the Permian mass extinction in the oceans was caused by global warming that left animals unable to breathe. As temperatures rose and the metabolism of marine animals sped up, the warmer waters could not hold enough oxygen for their survival.

The largest extinction in Earth’s history marked the end of the Permian period, some 252 million years ago. Long before dinosaurs, our planet was populated with plants and animals that were mostly obliterated after a series of massive volcanic eruptions in Siberia.

Fossils in ancient seafloor rocks display a thriving and diverse marine ecosystem, then a swath of corpses. Some 96 percent of marine species were wiped out during the “Great Dying”, followed by millions of years when life had to multiply and diversify once more.

What has been debated until now is exactly what made the oceans inhospitable to life — the high acidity of the water, metal and sulfide poisoning, a complete lack of oxygen, or simply higher temperatures.

New research from the University of Washington and Stanford University combines models of ocean conditions and animal metabolism with published lab data and paleoceanographic records to show that the Permian mass extinction in the oceans was caused by global warming that left animals unable to breathe. As temperatures rose and the metabolism of marine animals sped up, the warmer waters could not hold enough oxygen for them to survive.

The study is published in the Dec. 7 issue of Science.

“This is the first time that we have made a mechanistic prediction about what caused the extinction that can be directly tested with the fossil record, which then allows us to make predictions about the causes of extinction in the future”, said first author Justin Penn, a UW doctoral student in oceanography.

Researchers ran a climate model with Earth’s configuration during the Permian, when the land masses were combined in the supercontinent of Pangaea. Before ongoing volcanic eruptions in Siberia created a greenhouse-gas planet, oceans had temperatures and oxygen levels similar to today’s. The researchers then raised greenhouse gases in the model to the level required to make tropical ocean temperatures at the surface some 10 degrees Celsius (20 degrees Fahrenheit) higher, matching conditions at that time.

The model reproduces the resulting dramatic changes in the oceans. Oceans lost about 80 percent of their oxygen. About half the oceans’ seafloor, mostly at deeper depths, became completely oxygen-free.

To analyze the effects on marine species, the researchers considered the varying oxygen and temperature sensitivities of 61 modern marine species — including crustaceans, fish, shellfish, corals and sharks — using published lab measurements. The tolerance of modern animals to high temperature and low oxygen is expected to be similar to Permian animals because they had evolved under similar environmental conditions. The researchers then combined the species’ traits with the paleoclimate simulations to predict the geography of the extinction.

“Very few marine organisms stayed in the same habitats they were living in — it was either flee or perish”, said second author Curtis Deutsch, a UW associate professor of oceanography.

The model shows the hardest hit were organisms most sensitive to oxygen found far from the tropics. Many species that lived in the tropics also went extinct in the model, but it predicts that high-latitude species, especially those with high oxygen demands, were nearly completely wiped out.

To test this prediction, co-authors Jonathan Payne and Erik Sperling at Stanford analyzed late-Permian fossil distributions from the Paleoceanography Database, a virtual archive of published fossil collections. The fossil record shows where species were before the extinction, and which were wiped out completely or restricted to a fraction of their former habitat.

The fossil record confirms that species far from the equator suffered most during the event.

“The signature of that kill mechanism, climate warming and oxygen loss, is this geographic pattern that’s predicted by the model and then discovered in the fossils,” Penn said. “The agreement between the two indicates this mechanism of climate warming and oxygen loss was a primary cause of the extinction.”

The study builds on previous work led by Deutsch showing that as oceans warm, marine animals’ metabolism speeds up, meaning they require more oxygen, while warmer water holds less. That earlier study shows how warmer oceans push animals away from the tropics.

The new study combines the changing ocean conditions with various animals’ metabolic needs at different temperatures. Results show that the most severe effects of oxygen deprivation are for species living near the poles.

“Since tropical organisms’ metabolisms were already adapted to fairly warm, lower-oxygen conditions, they could move away from the tropics and find the same conditions somewhere else,” Deutsch said. “But if an organism was adapted for a cold, oxygen-rich environment, then those conditions ceased to exist in the shallow oceans.”

The so-called “dead zones” that are completely devoid of oxygen were mostly below depths where species were living, and played a smaller role in the survival rates. “At the end of the day, it turned out that the size of the dead zones really doesn’t seem to be the key thing for the extinction,” Deutsch said. “We often think about anoxia, the complete lack of oxygen, as the condition you need to get widespread uninhabitability. But when you look at the tolerance for low oxygen, most organisms can be excluded from seawater at oxygen levels that aren’t anywhere close to anoxic.”

Warming leading to insufficient oxygen explains more than half of the marine diversity losses. The authors say that other changes, such as acidification or shifts in the productivity of photosynthetic organisms, likely acted as additional causes.

The situation in the late Permian — increasing greenhouse gases in the atmosphere that create warmer temperatures on Earth — is similar to today.

“Under a business-as-usual emissions scenarios, by 2100 warming in the upper ocean will have approached 20 percent of warming in the late Permian, and by the year 2300 it will reach between 35 and 50 percent,” Penn said. “This study highlights the potential for a mass extinction arising from a similar mechanism under anthropogenic climate change.”

Jurassic ichthyosaur was warm-blooded, new research


This 15 June 2018 video says about itself:

Ichthyosaurs 101 | National Geographic

Meaning “fish lizard” in Greek, the aptly-named ichthyosaur once dominated the world’s oceans for millions of years. Learn about these prehistoric marine reptiles and see how features, such as basketball-sized eyes and a vertical tail, helped the ichthyosaur secure a place at the top of the ancient food chain.

From the North Carolina State University in the USA:

Soft tissue shows Jurassic ichthyosaur was warm-blooded, had blubber and camouflage

December 5, 2018

An ancient, dolphin-like marine reptile resembles its distant relative in more than appearance, according to an international team of researchers that includes scientists from North Carolina State University and Sweden’s Lund University. Molecular and microstructural analysis of a Stenopterygius ichthyosaur from the Jurassic (180 million years ago) reveals that these animals were most likely warm-blooded, had insulating blubber and used their coloration as camouflage from predators.

“Ichthyosaurs are interesting because they have many traits in common with dolphins, but are not at all closely related to those sea-dwelling mammals,” says research co-author Mary Schweitzer, professor of biological sciences at NC State with a joint appointment at the North Carolina Museum of Natural Sciences and visiting professor at Lund University. “We aren’t exactly sure of their biology either. They have many features in common with living marine reptiles like sea turtles, but we know from the fossil record that they gave live birth, which is associated with warm-bloodedness. This study reveals some of those biological mysteries.”

Johan Lindgren, associate professor at Sweden’s Lund University and lead author of a paper describing the work, put together an international team to analyze an approximately 180 million-year-old Stenopterygius fossil from the Holzmaden quarry in Germany.

“Both the body outline and remnants of internal organs are clearly visible,” says Lindgren. “Remarkably, the fossil is so well-preserved that it is possible to observe individual cellular layers within its skin.”

Researchers identified cell-like microstructures that held pigment organelles within the fossil’s skin, as well as traces of an internal organ thought to be the liver. They also observed material chemically consistent with vertebrate blubber, which is only found in animals capable of maintaining body temperatures independent of ambient conditions.

Lindgren sent samples from the fossil to international colleagues, including Schweitzer. The team conducted a variety of high-resolution analytical techniques, including time-of-flight secondary ion mass spectrometry (ToF SIMS), nanoscale secondary ion mass spectrometry (NanoSIMS), pyrolysis-gas chromatography/mass spectrometry, as well as immunohistological analysis and various microscopic techniques.

Schweitzer and NC State research assistant Wenxia Zheng extracted soft tissues from the samples and performed multiple, high-resolution immunohistochemical analyses. “We developed a panel of antibodies that we applied to all of the samples, and saw differential binding, meaning the antibodies for a particular protein — like keratin or hemoglobin — only bound to particular areas,” Schweitzer says. “This demonstrates the specificity of these antibodies and is strong evidence that different proteins persist in different tissues. You wouldn’t expect to find keratin in the liver, for example, but you would expect hemoglobin. And that’s what we saw in the responses of these samples to different antibodies and other chemical tools.”

Lindgren’s lab also found chemical evidence for subcutaneous blubber. “This is the first direct, chemical evidence for warm-bloodedness in an ichthyosaur, because blubber is a feature of warm-blooded animals,” Schweitzer says.

Taken together, the researchers’ findings indicate that the Stenopterygius had skin similar to that of a whale, and coloration similar to many living marine animals — dark on top and lighter on the bottom — which would provide camouflage from predators, like pterosaurs from above, or pliosaurs from below.

“Both morphologically and chemically, we found that although Stenopterygius would be loosely considered ‘reptiles,’ they lost the scaly skin associated with these animals — just as the modern leatherback sea turtle has,” Schweitzer says. “Losing the scales reduces drag and increases maneuverability underwater.

“This animal’s preservation is unusual, especially for a marine environment — but then, the Holzmaden formation is known for its exceptional preservation. This specimen has given us more evidence that these tissues and molecules can preserve for extremely long periods, and that soft tissue analysis can shed light on evolutionary patterns, relationships, and how ancient animals functioned in their environment.

“Our results were repeatable and consistent across labs. This work really shows what we’re capable of discovering when we perform a multidisciplinary, multi-institutional study of an exceptional specimen.”

Hagfish and lamprey ears, new study


This 2017 video says about itself:

The hagfish is a slime-emitting ocean-dweller that’s remained unchanged for 300 million years–and it shows. It has a skull (but no spine), velvet smooth skin, and a terrifying pit of a mouth that’s lined with rows of razor-sharp teeth.

From RIKEN in Japan:

Evolution of the inner ear: Insights from jawless fish

December 5, 2018

Researchers at the RIKEN Center for Biosystems Dynamics (BDR) and collaborators have described for the first time the development of the hagfish inner ear. Published in the journal Nature, the study provides a new story for inner ear evolution that began with the last common ancestor of modern vertebrates.

Comparing organs among related animals can be helpful when trying to understand the evolutionary process, and will ultimately help us better understand organogenesis — the process through which organs develop. This underlying philosophy helped guide the collaborative effort to study the inner ear led by Shigeru Kuratani at RIKEN BDR.

The story begins with a difference between jawed and jawless vertebrates. Jawed vertebrates like humans have inner ears with three semicircular canals, which are what allow us to sense our position and stay balanced in the world, and especially to sense 3-D acceleration. The fossil record shows that a group of jawless fish from the Paleozoic era only had two semicircular canals. In order to understand the evolutionary changes that led [to] three canals, the team looked at the only two types of jawless vertebrates that still exist on earth: lampreys and hagfish.

Lampreys are thought to have two semicircular canals, while hagfish only have one. However, hagfish are no longer thought to be more primitive than lampreys. A series of molecular biological experiments was able to clarify the issue. Analyzing the regulatory genes that control the development of the semicircular canals showed that the basic pattern of inner ear development is similar for all vertebrates, including lampreys and hagfish. Key genes, such as Tbx1 and Patched were expressed at the same places with the same timing across all three types of vertebrate.

The anterior and posterior canals in jawed vertebrates appear to be genetically homologous to the anterior and posterior parts of the lamprey canal, while the pattern for the single hagfish canal is likely an evolved trait, not a primitive condition. The difference between the jawed and jawless fish is the presence of the common crus, a structure that connects the anterior and posterior canals in jawed vertebrates. The current study could not determine whether the common crus is something that jawed vertebrates gained or something that was lost in jawless vertebrates.

Further analysis focused on the Otx1 gene. This gene is required for proper development of the lateral canal, the third canal that is unique to jawed vertebrates. The researchers found that despite the lack of a lateral canal, lampreys and hagfish both expressed Otx1 in the proper location during development. This was somewhat surprising as its expression was thought to be an advent that led to the evolution of the lateral canal. Instead, it appears that Otx1 expression in the otic vesicle is an ancient feature for all vertebrates.

A more complete understanding will be possible by performing studies with an animal that represents the lineages before jawed and jawless vertebrates diverged.

Cambrian animals’ eyes, new research


This video says about itself:

Colours of Life – The Evolution of Colour Vision Expressed in Musical Colours – Iris Stal

23 August 2018

A composition by Iris Stal.

This is a composition I wrote for a university assignment for a course on interdisciplinary evolution. It’s the very first composition I’ve ever written! 🙂 This piece for orchestra is supposed to express how colour vision has evolved throughout its evolutionary timeline, using musical colours.

Our eyes use cones to detect the colours in the light waves that we pick up. In the music, I attempted to explain which cones came up with which group of animals and how that affected the way they saw their environment. If important, I also tried to take important events or circumstances along in the atmosphere, such as natural selection influences or extinctions. I followed the lineage from one of the very first light-sensitive eyecups all the way up to human eyes. Lineages that branched off I didn’t include as it would be too much.

The coloured bars on the left show what cones the animals had. The cones symbolize cones for blue light, red, green and UV. I used video footage and/or illustrations that I edited to show how the species potentially perceived their environment. It’s not super accurate, but it’s hard imitating a colour the human eye can’t see. 😀 Looking at you, ultraviolet!

This project was sooo much fun to create! It was tons of work but it was absolutely worth the effort. I finished the project with a 9/10. It inspired me to continue with my passion for music. I hope you enjoy the video! 🙂

From the University of Bristol in England:

Enhancing our vision of the past

December 5, 2018

An international group of scientists led by researchers from the University of Bristol have advanced our understanding of how ancient animals saw the world by combining the study of fossils and genetics.

Ancestors of insects and crustaceans that lived more than 500 million years ago in the Cambrian period were some of the earliest active predators, but not much is known about how their eyes were adapted for hunting.

Work published in the Proceedings of the Royal Society B today suggests that when fossil and genetic data are assessed in tandem, previously inaccessible and exciting conclusions about long dead species can be made.

By examining the morphological characteristics of fossils’ eyes, alongside the genetic visual pigment clues, a cross-disciplinary team led by a collaboration between the University of Bristol’s Davide Pisani, Professor of Phylogenomics in the School of Earth Sciences and Nicholas Roberts, Professor of Sensory Ecology in the School of Biological Sciences, were able to find that ancient predators with more complex eyes are likely to have seen in colour.

Professor Pisani remarked: “Being able to combine fossil and genetic data in this way is a really exciting frontier of modern palaeontological and biological research. Vision is key to many animals’ behaviour and ecology, and understanding how extinct animals perceived their environment will help enormously to clarify how they evolved.”

By calculating the time of emergence of different visual pigments, and then comparing them to the inferred age of origin of key fossil lineages, the researchers were able to work out the number of pigments likely to have been possessed by different fossil species. They found that fossil animals with more complex eyes appeared to have more visual pigments, and that the great predators of the Cambrian period may have been able to see in colour.

Dr James Fleming, Professor Pisani and Roberts’ former PhD student, explained: “Animal genomes and therefore opsin genes (constituting the base of different visual pigments) evolve by processes of gene duplication. The opsin and the pigment that existed before the duplication is like a parent, and the two new opsins (and pigments) that emerge from the duplication process are like children on a family tree.

“We calculated the birth dates of these children and this allowed understanding of what the ancient world must have seemed like to the animals that occupied it. We found that while some of the fossils we considered had only one pigment and were monochromat, i.e. they saw the world as if looking into a black and white TV, forms with more complex eyes, like iconic trilobites, had many pigments and most likely saw their world in colours.”

The combinations of complex eyes and multiple kinds of visual pigments are what allows animals to distinguish between different objects based on colour alone — what we know as colour vision.

Professor Roberts commented: “It is remarkable to see how in only a very few million years the view those animals’ had of their world changed from greys to the colourful world we see today.”

The project involved scientists from all across the world — from the UK as well as Denmark, Italy, Korea and Japan, where Dr Fleming has now moved to work as a postdoctoral researcher. Each of them brought their own specialities to this multidisciplinary work, providing expertise in genetics, vision, taxonomy and palaeontology.

Sauropods, the biggest dinosaurs, how big?


This 28 November 2018 video says about itself:

SAUROPODS: The Largest Dinosaurs. Size comparison.

Species included: Thecodontosaurus, Melanorosaurus, Plateosaurus, Nigersaurus, Riojasaurus, Amargasaurus, Shunosaurus, Opisthocoelicaudia, Spinophorosaurus, Isisaurus, Camarasaurus, Diplodocus, Brontosaurus, Apatosaurus, Turiasaurus, Brachiosaurus, Mamenchisaurus, Barosaurus, Argentinosaurus.

Prehistoric sharks of central North America


This 4 December 2018 video from the USA says about itself:

When Sharks Swam the Great Plains

If you’ve ever been to, or lived in, or even flown over the central swath of North America, then you’ve seen the remnants of what was a uniquely fascinating environment. Scientists call it the Western Interior Seaway, and at its greatest extent, it ran from the Caribbean Sea to the Canadian Arctic.