Speaking of mammals, I think many people will think of various land creatures, including us humans, and most mammals live on continents and occupy much of Earth's oceans. Did mammals appear? What was the first mammal to appear in the ocean? What transformations and evolutionary processes have these marine mammals experienced? Many marine biology researchers have been exploring these questions for a long time and have discovered the process of the first mammal in the ocean. This mammal appeared around 50 million years ago and was also the first whale.
After some researchers examined the fossils they discovered, they discovered how these mainland creatures evolved during the Eocene (about 53 million years ago to 36,000 years ago). 5 million years), and that only). It took these creatures 20 million years to evolve from mammals toa length of 2.4 meters, living on the water's edge, eating fish and able to walk until they are today, whales of all sizes and shapes in the ocean process. In fact, researchers have discovered that the ancestors of these cetaceans are mesozoans.
Zhongbeast first lived near waterways, and this creature was a mammal. Researchers discovered that the first whale prototype was transformed step by step from this creature. In the process of evolution, walking whales are one of the forms. Research discovered this animal in Pakistan, and it is a type of half-terrestrial, half-marine animal that appeared 50 million years ago. The animal also has hooves. walks and the creature has very large feet. After 3 million years of development, this creature was transformed into Lode's whale. The body length of this creature is also 2.4 meters. Although this creationnature can walk on earth, it already has very special abilities. and a tail like a whale.
Ten million years after the appearance of the Lode whale, an ancient lizard whale appeared at a depth of 15 meters from the sea surface. This is a creature equipped with very small limbs which no longer have any function. At the same time, dolphins were also seen in the sea.
The reason why many researchers in the scientific field believe that the ancestors of marine mammals originated on the continent and evolved from he land animals is that scientists have discovered a very complete sentence in Pakistan: a cetacean skeleton, which researchers call that. discovery of the skeleton of a pakicetus.
Through extensive research on this skeleton, it was discovered that the bones behind the skull and limbs of this skeleton were very similar to those of theterrestrial artiodactyls of this period. The first whale creatures are believed to have been terrestrial. Only with the continuous changes in the living environment at that time did this animal have to enter the ocean and gradually evolved into a marine mammal. Researchers even deduced that the important reason why this land animal entered the ocean was the change in the land environment at that time, in the late Eocene. This is a very hot situation , but the earth's environment is not so dry at present, and some places that originally had dense tropical forests have gradually become very open places, which has brought comfort to some people's lives. mammals, allowing them to individuals grow larger and larger.
However, changes in the terrestrial environment are not very beneficial for all animals. Many carnivorous birds have alsocompletely disappeared from the earth. At this time, new carnivorous mammals appeared. these mammals are beginning to dominate the planet. When faced with a very dry season, long-hoofed carnivores have no way to adapt to changes in the terrestrial environment over time, and these animals are also at risk of extinction.
Under such circumstances, the pregnant ancient lizard whales, coupled with the first ice formation in the Antarctic and Arctic oceans, caused a disorder of ocean currents for the ancient lizard whales, suffering from a huge panic. to survive, this animal encountered some small toothed whales and considered this animal as food. Therefore, this animal survived slowly in the ocean.
Looking at the development and evolution of the Earth in the past, it is not difficult to see that every time the Earth undergoes changes inenvironmental or disasters, there will always be extinctions of animals or the emergence of new species. Some of the new species evolved from the original land creatures. Due to the continuous evolution and development of these earth creatures, rich and colorful creatures have appeared in nature, and only then can all kinds of creatures exist today. Together, they set solid conditions for the development and renewal of the land, and also. allowed us humans to understand various creatures. Having more knowledge plays an important role in understanding nature as a whole.
Why do ocean animals still survive during the many mass extinctions on Earth?
Jellyfish purchased in the aquarium have different lifespans depending on the species. The average lifespan is around a few months. The hardThe lifespan of common ornamental jellyfish is generally around 5 to 9 months, especially those living in aquariums. The museum's ornamental species and some jellyfish have shorter lifespans, such as some very small cupped jellyfish, which have a lifespan of approximately 2 to 4 weeks. The lifespan of jellyfish depends on the species. In captivity, jellyfish have an average lifespan. is about a few months. The most popular moon jellyfish has a lifespan of 12 to 18 months under normal feeding conditions, but under proper living conditions its lifespan can reach 20 years. To breed jellyfish well, try to imitate the ecological environment of the sea, such as water quality, water temperature, food plankton, water flow, trace elements in the jellyfish. water, light, etc. Among them, water quality, temperature, food and water flow are the four basic conditions.ntals necessary for the survival of jellyfish. Some special jellyfish have a longer lifespan, such as jellyfish, which also belong to the jellyfish category. Their lifespan is approximately one year. There is also a more special jellyfish called the “flagship jellyfish.” She has an important characteristic, that is, she can return to her juvenile stage after aging, so theoretically she can still survive.
Jellyfish are aquatic creatures. Their body structure has adapted to the ocean environment for a long time, so they are adapted to living in the water at all times and cannot be allowed out of the water. Water makes up the vast majority of jellyfish body composition. If left in water, they will feel uncomfortable and may die if the time is longer. Therefore, if you keep jellyfish as pets, try not to let them outr water.
The Earth experienced five mass extinctions before the appearance of humanity. As a result of these five mass extinctions, 80% of species were wiped out and 20% of species survived.< strong>And the vast majority of these 20% of species are creatures of the deep ocean, because the ocean has a longer capacity to resist disasters.
The five mass extinctions occurred in the Ordovician, Permian, Triassic and Cretaceous periods, respectively. The respective periods of occurrence should correspond to approximately 600 million years ago and 450 million years ago. 220 million years ago and 60 million years ago, the last mass extinction of organisms took place when the well-known dinosaurs became extinct. To be precise, there should be more than 6,600 yuan of fire dragons on earth. It has been around for a long time,about 150million years.The emergence of humans dates back only four to five million years, so these creatures have survived for a long time on earth.
Ocean creatures can survive disasters because life on land originated in the ocean. The deep ocean is more resilient to disasters and less affected by the outside world. Even if an asteroid hits the earth, as long as the ocean water is still at a normal temperature, there won't be much change, because. ocean water is The specific heat capacity is relatively large, and sea water is almost a whole, so its environment changes less, and deep-sea creatures are relatively old. For example, some of today's deep-sea creatures probably have <. strong>their ancestorsCreatures that lived 300 million years ago, that is to say the 3th extinction mass, havelived much longer than human life.
Human beings are constantly studying the creatures of the deep ocean because they have gradually discovered that there are many strange life forms in the ocean, because many life are native to the ocean and the nature of the ocean. is the cradle of many lives.People are trying to break the constraints of a certain existing biology by studying the existence and external forms of marine life, and even say that they can achieve the effect of prolonging life and immortality, but in fact it's just a beautiful thing.