Reproductive Conflict And The Evolution Of Menopause In Killer Whales

The evolutionary path of a whale is a fascinating process of a terrestrial mammal that evolves into a marine mammal. This evolutionary path started with one of the earliest ancestors called “Pakicetus”. A Pakicetus was discovered to be a land animal with four legs that had teeth as carnivores. It skull structure was long, but this organism didn’t look like any marine animal. The scientist then discovered that on the skull’s ear region it was surrounded by a bony wall. This feature on an organism only was distinct from one type of species, scientist discovered that this animal “Pakicetus” was an ancestor of a whale. By comparing the early whales Pakicetus to the next generation of ancestors Ambulocetus, the Ambulocetus whale looks more like

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.

There is no doubt that humans have always been intrigued with the majestic beauty of the large giants found in all of the world’s oceans. Whales and people have had a long history together, marked by many turns of events.

Recent evidence suggests that whales may not have always inhabited the oceans. Bones of an ancient ancestor of modern day whales, the Basilosaurus, were discovered in Pakistan that suggest whales evolved from a wolf-like creature. This genus of an early whale lived 34-40 million years ago in the late Eocene. These fossils show many different features in common with both modern day whales and modern day land mammals. Since the discovery of these bones, many other evidences show that whales are a likely descendant of the Basilosaurus through many different ways, such as embryologic comparison and DNA testing. Whales aren’t the only suspected descendants

By examining, they are too big, they don't get the right care/the whales hurt each other,

Anyone who has been to SeaWorld or even watched an episode of National Geographic can appreciate the savage beauty and strength of Orcinus Orca, also known as the killer whale. This is the largest and smartest member of the dolphin family and can be found in all parts of the world. In the past twenty years, thanks to researchers like Ken Balcomb in Puget Sound, scientists have been making radical discoveries about killer whales (Martin, 1993, p.111-114). Modern research has shown the killer whale to be a highly perceptive, super articulate animal that has an amazingly complex social structure indicative of previously unrecognized intelligence.

Based on this study, researchers can know what is the rate of fertilization and where mortality rate is greatest, also they can use this population to create a model population to see what is the cause and how they can prevent this. These results are important because it showed the evolution of the population and it helped to see if minimizing the threats is an effective solution and how these threats are affecting the right whales. Also, it can help assess the recovery of depleted populations, evaluate conservation threats and also to use whales as indicators of the health of local ecosystems (Fretwell 2014). Doing this study was complicated because the old population was not clear, and assumptions had to be made, such as the population size at each class. Therefore, the sample size can affect the end result. Also, assumptions had be made in the future population in regards of the population in each age class, but it was based from a journal.

Literally everyone who lives in cities knows that the world can be an extremely loud place. Marine life is immensely sensitive to under water noise. When the navy uses sonar, it causes noise in the world's seas, it agitates sea creatures that communicate through sound waves, such as whales. A study shows that whales' behaviors are altered by any exposure to sonar waves.

Me and my crew here on the waves of the Antarctic sea have not seen nor tracked any signs of a blue whale since our scientific equipment became operational two weeks ago. The blue whale, the largest animal on planet Earth, has been labeled as endangered on the conservation status chart for more than fifty years and has yet to change. Ever since the banning of blue whale hunting in 1966, blue whales have not increased in population at the rate we have predicted. To this day, even with all the limits hunters have on the ocean, blue whales struggle with accidental beaching and ship collisions.

The aquatic hierarchy is a carefully balanced ecosystem. With all the species intact and flourishing, the ocean thrives. But, like the great Pyramids of Egypt, if one component is out of place, the whole system collapses. This could lead to more danger than most people realize. For example, if the coral reefs are destroyed, sea turtles, fish, eels, and multiple other species would die. Or, if the Great White Shark went extinct, fish and seals would overpopulate and endanger the rest of the ecosystem. However distant this mass extinction seems, a small portion of it is slowly occurring before our eyes. Whales are only one of the multiple creatures suffering from our neglect, and not only are they suffering, but the hierarchy of ocean life and even us, as humans, are affected by this disastrous event.

As a person who grew admiring the wildlife, the rumor that numerous species of animals are currently experiencing major changes in life can be confirmed by myself. From global warming to over hunting and poaching, these species have strongly been affected by humanity’s increase in food and space as our dominance over the planet continues. One family of animals affected in numbers by man is the Cetaceans, the family of whales and dolphins, who for two centuries have been farmed by man in mass numbers for their sources in a process known as whaling. Whaling is a dangerous process, but in the short run, it is not as important as people tend to believe, not for humans but for the sake of the whales.

The Balaenoptera musculus, also known as the Blue Whale, is the largest animal in the world (Twister 1). These whales have been endangered since the eighteenth and nineteen hundreds and have been here as long as the dinosaurs roamed the Earth. They are members of the group of whales known as rorquals and are found in all the world’s oceans. They live on the upper layers of the open sea and are mostly found along the edges of the continental shelves (Zimmerman 1). Their habitat consists of polar and subtropical waters. Their lifestyle is diurnal and their group behavior is solitary (A-Z). These mammals may be extraordinary, but they are in vulnerable positions because of hunting, pollution, etc. Blue whales will result in extinction if we don’t

Over the millions of years, whales have adapted key traits to stay alive and best natural selection. The forelimbs of whales are modified into flippers, and the hind legs are reduced to internal vestiges. The tail is flattened into horizontal flukes and is used for propulsion. The head is very large, with a wide mouth and no external neck. Whales have one or two nostril openings, called blowholes, located far back on the top of the head; the nostril valves close and the lungs compress when the whale dives. Most whales must surface every 3 to 20 min to breathe, but some, can remain submerged for more than an hour. Whales have small eyes, designed to withstand great pressures, and most species have good vision. Their hearing is also excellent.

Every year tens of thousands of marine mammals are killed all over the world, with over twenty thousand small cetaceans killed in Japanese waters alone (Butterworth et al., 2013). These small cetaceans include various species of small whales, many dolphin species and some porpoises. They are killed in various manors, ranging from accidental ship strikes to the more morally controversial yearly drive hunts.

While the Japanese government justifies these actions by claiming that the research they are performing is ultimately for better management and conservation of cetaceans, these hunts are unnecessary. Instead of killing whales to perform these tests, there are non lethal research methods that could be used instead. According to the Japanese Whale Research Program under Special Permit in the Antarctic, also known as JARPA II, the data that they collect includes the monitoring of whales and krill abundance, the feeding ecology of whales, the effects of contaminants on cetaceans and their habitat, competition among whale species, and elucidation of temporal and spatial changes in stock structure (2016). Although this research is important, all