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Paleontology research on whales evolution
Evolution of whales essay
Paleontology research on whales evolution
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Its hard to believe that the large elegant marine mammals we know today, were once land dwelling creatures. Whales have been forever evolving just like humans. What is evolution? Evolution is the process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth (Mueller, Aug. 2010). Every living organism has evolved at one point or another. Whales have evolved from a land animal into an animal that lives only in the ocean.
Whales are believed to have come from land ancestors. The traditional theory of Cetacean evolution was that whales were related to Mesonychids, and extinct order of carnivorous animals (hoofed animals), which resembled wolves with hooves and
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They evolved to exploit this watery environment, developing streamlined bodies, remarkable feeding methods, and for toothed whales, the ability to "see" with sound. The first whales were Pakicetus, Ambulocetus, and Rodhocetus. The first whales of early Eocene epoch (56-34 million years ago), were believed to be a small mammal, about 50 pounds with dog-like legs, a long tail, and a narrow snout. The next whales were Protocetus, Maiacetus, and Zygorhiza. The next whales of late Eocene epoch, were able to swim faster and further. They had a long, seal-like body, powerful legs for propelling itself through the water, and nostrils that had already begun to migrate halfway up its forehead (a development foreshadowing the blowholes of modern whales). The giant prehistoric whales were Basilosaurus and friends. By about 35 million years ago, some prehistoric whales had attained gigantic sizes, bigger than the modern blue or sperm whale (Whale Evolution, no …show more content…
The adaptation from legs to fins and a tail are to make it faster and easier to swim through water. The blowhole has slowly moved to the top of the head, making it easier to breath while swimming. Whales also developed blubber, to us for energy during times when food is scarce or during long trips. In order to survive in the ocean whales had to adapt their lungs, so that they could breath easier and hold their breath for extended amounts of time when submerged underwater (Whale evolution and adaptation, no date). Whales have made many adaptations to make living in the ocean
The first goal was to accumulate the molecular phylogeny data for seahorses using the cytochrome b gene sequence information (S.P. Casey et al, 2004). In this particular study, the cytochrome b gene was used to investigate whether or not the Hippocampus was indeed pre-Tethyan in origin and to illuminate the relationship between Indo-Pacific and Atlantic seahorse species. Molecular markers like the cytochrome b gene were used to survey dispersal of seahorse species and to temporally define the evolutionary processes since much of the seahorse fossil record is deficient (Lourie et al.,
Scientists had some idea to the evolutionary process of whales. “It has always been clear that aquatic cetaceans must have evolved from terrestrial mammals and returned to the water, and the forelimbs of recent cetaceans still have the same general pattern as that of land mammals.” (Walking with Whales) It was known fact that land mammals and whales were related. However, the change from ancient whales to modern whales is drastic.
Shirihai, H. and B. Jarrett (2006). Whales, Dolphins and Other Marine Mammals of the World. Princeton, Princeton University Press. p.185-188.
Whales living in captivity become aggravated and have been known to take out anger on themselves by self harming. In the pools they live in, metal bars are placed in between the pools to prevent the killer whales from swimming to another pool. On several occurrences, the whales have attempted to bite and break the metal bars. This leaves the whales with broken teeth and a risk of infection. Infections in killer whales can lead to death in many cases. If a whale gets an infection, they have to be taken out of the pool and placed into another pool by themselves to prevent any problems with other killer whales they live with. In many cases, whales with infections need serious care from whale specialists.
The book In the Heart of the Sea: The Tragedy of the Whaleship Essex by Nathaniel Philbrick, is an inspiring story about an Essex from Nantucket, getting attacked by a eighty-five ton sperm whale miles deep out in the ocean. In these times, going on any ocean expedition had its precautions. While much focus on food, drinking water, medication and a method to cure illness, the most overlooked impairment was the creatures of the ocean. While the men of this vessel left the docks as predators, the survivors of the ninety- three-day journey on three small harpoon boats came back as prey. This story gives a great depiction of the potential of the sperm whale as well as the devastation that they can bring.
The origin of modern day whales, a mystery that has puzzled paleontologists for years, may have just been solved with the discovery of an ankle bone. This discovery might sound simple and unimportant, but the bones of these ancient animals hold many unanswered questions and provide solid proof of origin and behavior. The relationship between whales and other animals has proven to be difficult because whales are warm-blooded, like humans, yet they live in the sea. The fact that they are warm-blooded suggests that they are related to some type of land animal. However, the questions of exactly which animal, and how whales evolved from land to water, have remained unanswered until now.
These whales had well developed limbs, but were aquatic. However, unlike land mammals, this species did not have the vertebrae in the pelvis fused together into a sacrum. Early whales, such as Pakicetus, show many of the same features and qualities as an early group of land mammals known as mesonychids, which are also close to hoofed mammals like the Eohippus! In fact, some fossilized teeth that were identified at one point as mesonychids (large carnivorous land mammals) are now known to have come from archaeocetes (these primitive
Within the whale’s mouth is a face with a large hooked nose, which is thought to be an ancestor who once had an important interaction with a whale in the mythical past, signifying the whale emblem of their family
Orca whales do not like to be taken from their family, held captive for many decades and put with other whales that they do not know. No other living organism on this planet would like to be put through the same thing. Orca whales are highly social animals, they are very intelligent, and are very emotional. If they are kept away from other whales, fed intermittently and received little attention from staff makes them get very emotional and can lead to death of people and the whales. Orca whales should not be held captive; they are beautiful creatures that are not great for people’s amusement and if they are treated poorly, they will act poorly.
Fin Whales play a huge part in regulating the food flow in the ocean by stabilizing the food chain. Without whales we would see species overpopulating the ocean, and the food chain will be interrupted. Whalefacts.org reports that even whale waste helps the environment by reducing the carbon in the atmosphere. They also showcase studies that have proven that other whales like the sperm whale's poop, "helps stimulate the growth of phytoplankton which pull carbon from the atmosphere to provide a cleaner and healthier breathing environment for all animals." Fin Whale and other whales poop also helps with the growth of phytoplankton, in which other species depend on for survival. Whales are detrimental to the ocean, they all play a huge role in
That “prehistoric” whales had the jaw of a wolf (a fifty million year old wolf to be exact) and the ear of a whale. I think that all of our semiaquatic mammals play a big part in the evolution of land mammals to water mammals. Like at some point of say an otter’s life, nature told it to stop evolving so that it wouldn’t become completely marine, but semiaquatic as we named it. How did it know when to stop evolving? Was it changes in the environment? Or the need for survival? Which brings around another question, how did we go from a planet of just rock and magma, to a planet thriving with
Orcas, or killer whales are majestic giants of the sea. They are actually the largest type of dolphin. They have long black bodies with distinct white patches near their eyes. A killer whale can be up to 32 feet or more in length, and weigh up to 12,000 pounds. Females are a bit smaller, but live longer (Gorman). The name “killer whale” apparently came not because it is a vicious whale, but because it preys on whales. They do not have any natural predators, and they are considered the “top dog” of the ocean. Not even the great white shark stands a chance against these superb killers. “Unlike sharks, killer whales are cautious hunters, sometimes spending hours harassing a 1,000-pound sea lion so it can easily be drowned” (Francis). Orcas use many hunting tactics that are unique to their species, which is what makes them invincible.
Killer whales are basically the same shape as fish, but they differ in many ways. One of the most obvious differences is the tail fin. Fish have vertical tail fins, while whales have horizontal tail fins. One of the most distinctive features of orcas is the tall, wide dorsal fin located on its back. In females, the dorsal fin can grow to about 2 feet high. It is falcate (hooked or curved). In males, the dorsal fin is triangular in shape and can grow up to about 6 feet high. Another distinctive feature of killer whales is that they possess a sleek, black and white pigmentation pattern. A white patch is located above and behind the eye. An extensive white ventral patch extends onto the flanks (sides). "There is a gray saddle behind the dorsal fin, which is black at birth." (Hoyt, Pg. 32)
Humpback whales breath voluntarily, unlike humans. Since they have to remember to breath, researchers believe humpbacks sleep by shutting off half of their brain at a time. Like orcas and dolphins, humpback whales have noses at the top of their head called blowholes (Animal Planet). Humpback whale calves do not stop growing until they are ten years old (National Geographic). They breed, give birth and care for their newborn calves in the warm waters of Tonga. Instead of teeth, humpbacks have baleen plates, they are brush-like strands of bristle that trap there food until it is swallowed. They have very odd mouths that curve downwards, like an eternal frown. Humpback whales are amazing marine mammals (Big Animal Expeditions)
In 1986, The International Whaling Commission (IWC) implemented a moratorium to stop commercial whaling. Many people believe that this would save the whales and end forever the industrial slaughter that had decimated the many different species. Being an animal lover and just getting back from Florida for over a year, I realized how beautiful and important the ocean and the animals that live in it are. In Florida I saw many different types of ocean species, but I have never seen a whale in real life. And that made me think. How protected are these animals? I have watched television programs about entire fleets of ships, and even a helicopter, out following whaling ships trying to sabotage their efforts in order to save as many whales as possible. What are the loopholes that these whalers are slipping through to still be able to kill these majestic creatures?