Oceans get rid of bondage and grow? Why are whale so big?

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 Oceans get rid of bondage and grow? Why are whale so big?


When I first met the sea lion face to face, I almost screamed. I was snorkeling with a venting tube, and for a long time I had a colorful coral. Suddenly, I looked up and saw a huge animal. It was not far from my mask. It has milky white eyes and long canine teeth, indicating that it has close evolutionary relationship with land carnivores such as bears and dogs. The most disturbing thing is that it is really big. The mammals in the ocean are often large. Seals, sea lions and walruses are often muscular and full of flesh. So is the manatee and the gong. And whale is almost a huge pronoun. Since entering the underwater world, the size of the fur covered mammal family has expanded over time. Why is that? Most of the explanations for this trend are attributed to the fact that the ocean is a free environment. Water allows mammals to get rid of some gravity so that they can evolve into heavy bodies that cannot be sustained on land. Water prevents them from being restricted by the scope of their activities, allowing them to find food in a wider space. It turns out that these animals can only get a small amount of food from the land, and now they can enjoy a lot of plankton, crustaceans and fish under the water. But William Jordi of Stanford University has put forward very different explanations. WilliamGearty For him, the sea has made mammals bigger, not because the ocean has allowed them to get rid of their bondage, but because they have imposed new restrictions. Jordi explained that after entering the water, their bodies lose heat, but they do not lose heat in land or air. In order to make up for the continuous heat loss, humans use underwater diving suits, whale relies on blubber to warm themselves, and otters rely on thick fur. He said, the easiest way to make up for the loss of heat is the size of the body. As the body expands, the volume increases faster than the surface area, so the body produces more heat than the loss of heat from the skin. But animals cant grow indefinitely, because larger bodies mean more energy needs. The amount of food they can find, catch and swallow is limited. As a result, the demand for heat has increased the size of marine mammals, and the demand for food has put their bodies in the upper limit. Jordi found that the size difference between them was surprisingly small, far less than the difference between land mammals. Jordi, together with Jonathan Payne (JonathanPayne) of the Stanford University and Craig McLean (CraigMcClain) of the Maritime Association of the University of Louisiana, collects the size data of nearly 7000 mammals, including extinct animals. He pointed out that marine mammals, such as whale, manatees and seals, each had an average optimum mass of 500 kg. However, many mammals differ significantly in weight, and sperm whales and dolphins are apparently not the same. But what is important is that the magnitude of change in the ocean is much lower than that on land. The smallest aquatic mammals are thousands of times larger than the smallest terrestrial mammals, but the largest aquatic mammals are 25 times larger than the largest terrestrial mammals, Jordi said. I find that no one has noticed this before. This is very strange. This explanation is different from the fact that the oceans allow mammals to get rid of bondage. On the contrary, it shows that water exerts strict restrictions on them. In order to thrive, they must maintain a suitable body size and a large body shape, but not too big or too small. Jordi can use a set of equations to calculate the boundary of this Goodey Rock band (GoldilocksZone, the best condition for survival). These equations relate the size of a mammal to the amount of heat it loses and the speed at which food is found. The equation not only calculated the optimal average weight of marine mammals at about 500 kg, but also calculated that the weight of all marine mammals fluctuated within the narrow range of the ideal value. These two calculations are consistent with the results of three researchers such as Jordi. Samantha Price of Clemson University (SamanthaPrice) devoted himself to studying mammalian evolution. She says it makes sense, but evolution is complex, she said. But the factors that cause the size of these animals are not just the demand for heat. It has also been suggested that factors such as buoyancy increase make marine mammals more likely to evolve into the Goodey Rock belt type. There are no exceptions in biology. For example, in marine mammals, sea otters are especially small, roughly as large as Labradors. This is probably because their fur is so thick that there are as many as 1 million hairs per square inch (6.4 square centimeters), and they can keep warm and do not have to be bigger. Moreover, much of their time is spent on land, with little energy loss. The most extreme example is baleen whales, whose weight exceeds the average value of 500 kg. The largest blue whale can weigh up to 180 thousand kilograms. The blue whale and its huge relatives appeared only in the last million years of whales evolution, and Smithsons NickPyenson explained why. About 3 million years ago, changes in glaciers, winds and currents produced a lot of nutrients in coastal waters, making large groups of crustaceans and small fishes thriving, and they became the whale food. The distribution of these delicacies is not uniform. They are concentrated in very remote places, like a buffet restaurant, where lots of delicious food are gathered, while food in other places is as scarce as desert. This is the reason why the whale has evolved a huge body, he said. They are very good at searching for dense prey. The huge size allows them to survive without food for a long time. They also developed a feeding technology called swoop feeding, that is, speeding up the rush into the prey, opening huge mouths, inhaling large quantities of sea water, and making it difficult for the prey to escape. The advent of mass food and the development of whaling technology enabled them to break through the upper limit of body weight that other marine mammals could not surpass. Therefore, whale, instead of the manatee or seal, has become the largest animal ever recorded. Source: NetEase science editor: Guo Hao _NT5629 The distribution of these delicacies is not uniform. They are concentrated in very remote places, like a buffet restaurant, where lots of delicious food are gathered, while food in other places is as scarce as desert. This is the reason why the whale has evolved a huge body, he said. They are very good at searching for dense prey. The huge size allows them to survive without food for a long time. They also developed a feeding technology called swoop feeding, that is, speeding up the rush into the prey, opening huge mouths, inhaling large quantities of sea water, and making it difficult for the prey to escape. The advent of mass food and the development of whaling technology enabled them to break through the upper limit of body weight that other marine mammals could not surpass. Therefore, whale, instead of the manatee or seal, has become the largest animal ever recorded.