⒈ Research Paper On Baleen Whales

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Research Paper On Baleen Whales



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Facts: The Baleen Whale

Further research suggests that the baleen of Aetiocetus was arranged in bundles between widely spaced teeth. If true, this combination of baleen and dentition in Aetiocetus would act as a transition state between odontocetes and mysticetes. This intermediate step is further supported by evidence of other changes that occurred with the evolution of baleen that make it possible for the organisms to survive using filter feeding, such as a change in skull structure and throat elasticity.

It would be highly unlikely for all of these changes to occur at once. Therefore, it is proposed that Oligocene aetiocetids possess both ancestral and descendant character states regarding feeding strategies. This makes them mosaic taxa , showing that either baleen evolved before dentition was lost or that the traits for filter feeding originally evolved for other functions. It also shows that the evolution could have occurred gradually because the ancestral state was originally maintained.

Therefore, the mosaic whales could have exploited new resources using filter feeding while not abandoning their previous prey strategies. The result of this stepwise transition is apparent in modern-day baleen whales, because of their enamel pseudogenes and their in utero development and reabsorbing of teeth. If it is true that many early baleen whales also had teeth, these were probably used only peripherally, or perhaps not at all again like Dall's porpoise, which catches squid and fish by gripping them against its hard upper jaw. Intense research has been carried out to sort out the evolution and phylogenetic history of mysticetes, but much debate surrounds this issue.

A whale's baleen plates play the most important role in its filter-feeding process. To feed, a baleen whale opens its mouth widely and scoops in dense shoals of prey such as krill , copepods , small fish , and sometimes birds that happen to be near the shoals , together with large volumes of water. It then partly shuts its mouth and presses its tongue against its upper jaw, forcing the water to pass out sideways through the baleen, thus sieving out the prey, which it then swallows.

Whale baleen is the mostly mineralized keratin-based bio-material consisting of parallel plates suspended down the mouth of the whale. Baleen's mechanical properties being strong and flexible made it a popular material for numerous applications requiring such a property see Human uses section. The basic structure of the whale baleen was characterized to be a tubular structure with a medulla hollow core enclosed by a tubular layer with a diameter varying from 60 to microns, which had approximately 2.

The elastic module in the longitudinal direction and the transverse direction are MPa and MPa, respectively. This difference in elastic module could be attributed to packing of the sandwiched tubular structure. Hydrated versus dry whale baleen also exhibit significantly different parallel and perpendicular compressive stress to compressive strain response. Although parallel loading for both hydrated and dry samples exhibit higher stress response about 20MPa and MPa at 0. Crack formation is also different for both the transverse and longitudinal orientation. For the transverse direction, cracks are redirected along the tubules, which enhances the baleen's resistance to fracture and once the crack enters the tubule it is then directed along the weaker interface rather than penetrating through either the tubule or lamellae.

People formerly used baleen usually referred to as "whalebone" for making numerous items where flexibility and strength were required, including traditional baskets, backscratchers , collar stiffeners , buggy whips , parasol ribs, switches, crinoline petticoats, and corset stays. It was commonly used to crease paper ; its flexibility kept it from damaging the paper. It was also occasionally used in cable-backed bows.

Synthetic materials are now usually used for similar purposes, especially plastic and fiberglass. Baleen was also used by Dutch cabinetmakers for production of pressed reliefs. In the United States, the Marine Mammal Protection Act in makes it illegal "for any person to transport, purchase, sell, export, or offer to purchase, sell, or export any marine mammal or marine mammal product [8] ". Baleen serves as a habitat for some species from the gastropod families Pyropeltidae , Cocculinidae , Osteopeltidae , and Neolepetopsidae. From Wikipedia, the free encyclopedia. Keratin structure in whales, used for flexible stiffening. For other uses, see Whalebone disambiguation. Baleen hair is attached to each baleen plate.

Aquatic Mammals. PMC PMID Archived from the original PDF on Systematic Biology. It can make people curious — beached whales can do strange things, like explode. It can also be upsetting to witness a creature so magnificent in water reduced to lifeless blubber on land. What rarely registers, however, is the lost opportunity for carbon sequestration. Whales, particularly baleen and sperm whales, are among the largest creatures on Earth. Their bodies are enormous stores of carbon, and their presence in the ocean shapes the ecosystems around them. From the depths of the ocean, these creatures are also helping to determine the temperature of the planet — and it's something that we've only recently started to appreciate.

Humans have killed whales for centuries, their bodies providing us with everything from meat to oil to whalebone. The earliest record of commercial whaling was in CE. The bodies of whales, among the largest creatures on Earth, are huge stores of carbon Credit: Alamy. When whales die, they sink to the ocean floor — and all the carbon that is stored in their enormous bodies is transferred from surface waters to the deep sea, where it remains for centuries or more.

In the study, scientists found that before industrial whaling, populations of whales excluding sperm whales would have sunk between , to 1. But when the carcass is prevented from sinking to the seabed — instead, the whale is killed and processed — that carbon is released into the atmosphere. Andrew Pershing, a marine scientist at the University of Maine and an author of that study, estimates that over the course of the 20th Century whaling added about 70 million tonnes of carbon dioxide into the atmosphere. The US currently has million cars," he says. But whales are not only valuable in death. The tides of excrement that these mammals produce are also surprisingly relevant to the climate. Whales feed in the deep ocean, then return to the surface to breathe and poo.

Their iron-rich faeces creates the perfect growing conditions for phytoplankton. Whale poo is a powerful fertiliser for the ocean's phytoplankton, which have a large potential to capture carbon Credit: Alamy. For instance, as whale populations declined, the orcas that predated them turned to smaller marine mammals like sea otters. The otters subsequently declined, leading to the spread of sea urchins, which munched away the kelp forests around the North Atlantic — with a knock-on effect on marine carbon sequestration.

What this means is that restoring whale populations to their pre-whaling numbers could be an important tool in tackling climate change, sequestering carbon both directly and indirectly, and thus helping to make a small dent in the enormous volume of CO2 emitted by fossil fuels every year. There have been various other proposals for how to achieve this reduction, including tree-planting and stimulating phytoplankton blooms by adding iron to the ocean, a form of geoengineering known as iron fertilisation.

But tree-planting requires a scarce resource: terrestrial land, which may already be in use as another valuable habitat or farmland. The beauty of restoring whale populations is that there is plenty of space in the ocean — space once filled with whales. The resulting plumes of whale poo would also vastly outstrip the potential of ocean iron fertilisation. It would take successful blooms per year to match the potential of a fully restored whale population, according to Pershing's study.

Marine phytoplankton capture carbon dioxide through photosynthesis, acting as a carbon sink Credit: Alamy.

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