Christmas is almost here, so what better topic to post on than the evolution of the whales!?!?
65 million years ago the earth was devastated by a catastrophic meteor impact that resulted in the death of the dinosaurs. Mammals back then had been slowly evolving but remained small and mostly nocturnal, yet when the dinosaurs perished they quickly took over abandoned niches in the skies, land and water becoming one of the most incredible dynasties the world has ever seen. Some of the most beautiful of this diverse group are the marine mammals, the cetaceans (whales, dolphins etc). The ancestor of the whales left life on land to make the oceans their home. With over 86 species existing today of whales, dolphins and other marine mammals, they make up the order Cetacea which include the magnificent blue whale reaching a whopping 30 metres in length to the little known porpoise species, Vaquita reaching only 4.5 metres long. The evolution of the whales is documented in an incredibly rich fossil record dating back to over 50 million years ago…
Pakicetus, 50 million years ago Pakicetus is regarded as the most basal (earliest) whale. Although Pakicetus primarily lived on land, it is the first of the land mammals to show significant developments towards a future in ruling the oceans. Pakicetus is known from only a few incomplete specimens found in Pakistan but it is predicted to have been about a metre in length. Interestingly, Pakicetus was an artiodactyl (or even-toed ungulate, an order which includes the giraffes, camels, pigs and cows), however, Pakicetus shows some defining characteristics of evolving for life in the water such as elongation of the skull and body and the teeth begin to lose the heterodontus nature. The eyes of Pakicetus were also high on its head suggesting a capability to hunt not only on land but in water too.
Ambulocetus, 49 million years ago Ambulocetus literally means “walking whale” and shows more extreme divergence towards an aquatic lifestyle. Ambulocetus shows even greater elongation of the skull and simplification of its dental morphology. Unlike the marine reptiles of a bygone era, Ambulocetus would have swam through the water with vertical motion. The morphology of Ambulocetus’ inner ear is also similar to that of modern cetaceans meaning it could probably hear well underwater. Ambulocetus also shares some similarities with modern crocodiles such as high nostrils, pointed teeth and a long skull, making it likely that Ambulocetus was a deadly ambush predator, a far cry from its gentle giant descendants.
Rodhocetus, 46 million years ago
Rodhocetus fossils are also restricted to Pakistan and beautifully depict a familiar whale like skeleton with much shorter limbs and elongated hands and feet (that were most likely webbed). The nasal openings of Rodhocetus has also moved higher up the skull and closer to the eyes. Again, Rodhocetus shows specific morphologies that are characteristic of artiodactyls, they have a double-pulley astralagus (heel bone) found in all modern even toed ungulates.
Basilosaurus, 37 million years ago Basilosaurus is probably the earliest skeleton that very closely resembles modern whales, the name means “king lizard” which is highly inaccurate but fits well when considering that Basilosaurus had a long and slender body that could reach an almighty 18 metres in length. Basilosaurus also shows an extraordinary reduction in limb size compared to its ancestors meaning it is in no way adapted to live on the land any longer. At the time of Basilosaurus’ existence it was one of the largest marine animals to have existed since the days of marine reptiles (such as Liopleurodon and Mosasaurs). The teeth of Basilosaurus had similar morphology to modern killer whales indicating they were highly active hunters.
The whales of today are some of the most remarkable creatures to have ever existed. We often stand and stare in awe at the immense sizes of prehistoric marine animals in museums and it is easy to forget that we are living at the same time of the largest animals to have ever existed, past of present, the whales. We then often neglect to appreciate how magnificent these creatures are. Sadly this has led to a massive depletion in their numbers and diversity due to pollution, fishing and hunting. The whales and all other cetaceans have some of the most wonderful social structures known in the animal kingdom as well as incredible intelligence. In the last 50 million years this order has conquered oceans across the world and delighted humans all over. Cetaceans are fast becoming more endangered and if we do not act, in years to come our descendants will wonder how their ancestors let these wonderful creatures slip through their fingers.
Corrupt Moldavite! Her attack is ramming with her horns but if made in contact with land it makes a small meteor like impact, which creates glass-like shards. (attack based on the creation of Moldavite). Her fin like tail, kicks up dust and dirt as she runs.
Ever thought of the possibility that the world would end before 2012 in a nuclear war or a meteor impact? Had the prophecy been made around 1800, people would just rejoice and go “Lucky! The world won’t end till 2012, so not in my lifetime!”, wouldn’t they? Though most people would probably ignore it. That’s what I’m saying. What those so-called ‘prophets’ are good at is in fact just exaggerating rumors to frighten people. Though, I’m not saying there are no real prophets among them. For instance…consider Izaya. He’s sort of like a prophet isn’t he? Isn’t he always saying mysterious things as if he could read your mind? He’ll appear like a ghost everytime something happens, and act as if everything’s happening the exact way he had expected, but he is actually as clueless as everyone else beforehand. Everything is obvious with the benefit of hindsight. Just like those self-proclaimed prophets, all he does is talk about things that have already happened as if he had expected them long in advance. What’s unusual about Orihara Izaya is that he can make talks very convincing. If you analyze his talks with a clear head, they probably won’t be enough to take you in… But he’ll always make sure to arrive on the scene at the best time and say the worst possible thing in your ear, so that you can’t help but be unnerved. If Izaya were to debut as a prophet on television, he’d get pretty high ratings. Of course, when his following has reached a certain size, he would probably get tired of it, toss out a big prophecy such as “Japan is going to be submerged” and simply disappear into the commotion it would cause. He was already good at coaxing and cajoling back when we were still in school. Rather than ‘tricking’ or ‘deceiving’, I’d rather say he’s good at coaxing. So good that it’s almost a waste. Really, my high school days were ruined thanks to those two. Shizuo was violent and Izaya was shady as hell, so no girls were willing to approach us. Not that I wanted any other girl when I was already living with Celty, of course. Anyway, the point is, never believe a word Izaya says. Unlike those self-proclaimed prophets, there’s not even an ounce of good will in his words. But then, his lies aren’t any more palatable even if he does say them with good will.
Evidence of Martian life could be hard to find in some meteorite blast sites
Scientists in their preliminary findings suggest signs of life from under Mars’ surface may not survive in rocks excavated by some meteorite impacts.
Scientists analysing samples from Mars’ surface have so far not conclusively detected organic compounds that are indigenous to Mars, which would be indicators of past or present life. The inconclusive results mean that researchers are now suggesting that a good place to find these organic compounds would be deep underground - from rocks that have been blasted to the surface by meteor impacts. This is because such rocks have been sheltered from the Sun’s harmful radiation and from chemical processes on the surface that would degrade organic remains.
Now, a team of scientists from Imperial College London and the University of Edinburgh has replicated meteorite blasts in the lab. The aim of the study was to see if organic compounds encased in rock could survive the extreme conditions associated with them being blasted to the surface of Mars by meteorites. The study, published today in Scientific Reports, suggests that rocks excavated through meteorite impacts may incorrectly suggest a lifeless early Mars, even if indicators of life were originally present.
In the study the team replicated blast impacts of meteorites of around 10 metres in size. The researchers found that the types of organic compounds found in microbial and algal life - long chain hydrocarbon-dominated matter- were destroyed by the pressures of impact. However, the types of organic compounds found in plant matter - dominated by aromatic hydrocarbons - underwent some chemical changes, but remained relatively resistant to impact pressures. Meteorites often contain organic matter not created by life, which have some similarities in their organic chemistry to land plants. The team infer that they also should also be resistant to blast impacts.
Their study could help future missions to Mars determine the best locations and types of blast excavated rocks to examine to find signs of life. For example, it may be that meteorite impacts of a certain size may not destroy organic compounds or scientists may need to concentrate on rocks excavated from a certain depth.
Professor Mark Sephton, co-author of the research from the Department of Earth Science and Engineering at Imperial College London, said: “We’ve literally only scratched the surface of Mars in our search for life, but so far the results have been inconclusive. Rocks excavated through meteorite impacts provide scientists with another unique opportunity to explore for signs of life, without having to resort to complicated drilling missions. Our study is showing us is that we may need to be nuanced in our approach to the rocks we choose to analyse.”
Dr Wren Montgomery, co-author of the study from the Department of Earth Science and Engineering, added: “The study is helping us to see that when organic matter is observed on Mars, no matter where, it must be considered whether the sample could have been affected by the pressures associated with blast impacts. We still need to do more work to understand what factors may play an important role in protecting organic compounds from these blast impacts. However, we think some of the factors may include the depths at which the rock records are buried and the angles at which meteorites hit the Martian surface.”
Previous in situ analyses of the Martian terrain have found inconclusive evidence for the existence organic compounds - so far only finding chlorinated organic matter. The issue for scientists has been that it is not easy to look at simple chlorine-containing organic molecules and determine the origin of the organic compound components.
NASA’s Viking landers in 1976 detected chlorine-containing organic compounds, but they were thought to be chemical left-overs from cleaning procedures of Viking’s equipment before it left Earth. Later, the Phoenix Mission in 2008 discovered chlorine-containing minerals on the Martian surface, but no organic compounds. In 2012 the Mars Science Laboratory Mission detected chlorinated organic matter, but they thought that the analysis process, which involved heating chlorine containing minerals and carbonaceous material together, was producing chlorine-containing organic compounds. Working out whether the source of the carbon found on Mars was carried once again from Earth or was indigenous to Mars remains frustratingly difficult for scientists.
The team carried out their research by subjecting the different types of organic matter to extreme pressure and temperature in a piston cylinder device. They then did a chemical analysis using pyrolysis-gas chromatography mass spectrometry.
The next steps will see the team investigating a broader range of pressures and temperatures, which would help them understand the likely effects of a greater range of meteorite impacts. This would enable them to identify the specific conditions under which organic material may escape the destructive effects of blasts - even when excavated from deep underground by violent events. This could help future Mars missions further refine the types and locations of rocks that they can analyse for signs of past or present life.
The Richat Structure or “The Eye of the Sahara” is a mysterious geological formation in Mauritania. Scientists used to think it was the site of a meteor impact or volcanic eruption. Now, the leading theory is that a symmetrical dome of sedimentary rock was eroded away, revealing nested layers.
Top Image: A false color image of the structure from the Landsat 7 sensor, using the infrared and green channels. Credit: NASA/USGS.
GIF: The Richat Structure can be seen from space - a tiny bullseye in the middle of the desert.
Middle image: An exaggerated topographical map of the structure. Brown=bedrock, pale yellow = sand, green = vegetation, blue = salty sediments=blue. Credit: NASA/JPL/NIMA
Bottom image: A true color photo of the eye. Credit: NASA/GSFC/METI/Japan Space Systems,and U.S./Japan ASTER Science Team
A new study published by NASA researchers seems to confirm that 4-4.5 billion years ago almost the entire planet was showered in an intense bombardment of giant asteroids.
This period would’ve effected the whole planet, essentially melting the surface into molten rock multiple times over, boiling any water oceans into a steam-atmosphere and dramatically altering the geological landscape.
Heavy thumping penetrated the cockpit, indicating that something was moving in the ship’s direction. This was confirmed a moment later by Rey’s scream in response to the appearance of a giant radial mouth that all but covered the forward port. The tooth-filled mouth belonged to a rathtar, which, perceiving the presence of living non-rathtars inside the craft, was chewing its damnedest to get at them. Designed to protect against high-velocity meteoric impacts, the port suffered no immediate damage. Rathtars were notably persistent, however, and frustration only led them to redouble their efforts. Like the rest of them, their mouthparts were exceptionally robust. Design or not, Han had no intention of waiting around long enough to see whether the material of which the port was composed was tougher than rathtar dentition. “This is not how I thought this day would go,” he muttered.
It’s always fascinating when looking at the Moon through a telescope, to look for the landing sites of the Apollo missions. It is sometimes hard to comprehend that what I’m looking at, this gigantic ball of rock some 384,000km away, has been walked on by a species on our planet.
It looks like a completely desolate wasteland battered by asteroid and meteor impacts.
Fear has grown, fear so old Fear is pulsing in my skull [
Grey came to a skidding halt just after dashing out of the near building. His arm flew up to protect his face from the meteor’s explosive impact that nearly crushed him. He’d have to be more careful. Now the monstrous demon was rising from broken foundation, the young mage would not be able to escape combat the entire invasion - or his fear.
((The first round of demons Grey mostly ran from, he’s not actually combat experienced! pt.2))