Dinosaurs are a class of reptiles that belong to the main dragon class, and they appeared in the late Triassic period, about 2300 million years ago, a long time ago. Dinosaur names mean "terrible lizards", but in reality, dinosaurs were not lizards, they had different bone structures and physiological characteristics from lizards. The bodies of dinosaurs were usually large, and some even reached a length of tens of meters, such as long-necked dragons, Tyrannosaurus rex, etc. The reason why dinosaurs were able to be so large may have something to do with their internal thermality, that is, dinosaurs were able to regulate their body temperature without being completely dependent on the outside temperature. This allowed dinosaurs to survive in a variety of environments and have a higher metabolic rate and mobility.
Dinosaurs reached their peak in the Jurassic and Cretaceous periods of the Mesozoic Era, and they occupied various ecological niches on Earth, some were herbivorous, some were carnivorous, some were amphibious, some were flying, and some were even covered with feathers. The diversity and adaptability of dinosaurs is amazing, they have few natural predators and are the overlords of the planet. However, at the end of the Cretaceous period, about 65 million years ago, the dinosaurs suddenly became extinct, and only the bird branch survived. Why did dinosaurs go extinct?This is a mystery that has long puzzled scientists and the public.
Currently, the most potent cause of dinosaur extinction is the asteroid impact theory, that is, an asteroid with a diameter of about 15 kilometers hit the Yucatan Peninsula in southern Mexico at a speed of 20 kilometers per second 65 million years ago, causing a series of catastrophic consequences that led to the extinction of dinosaurs and many other creatures. The evidence for this claim is mainly as follows:
Iridium anomalies. On Earth, iridium is a very rare element, but it is more abundant on asteroids and comets. At the boundary of the extinction of the dinosaurs, at the junction of the Cretaceous and Paleogene periods, scientists found unusually high levels of iridium, 30 to 160 times higher than normal. This shows that when the dinosaurs were extinct, an iridium-rich celestial body hit the earth, scattering a large amount of iridium on the earth's surface.
Crater. At the bottom of the Yucatan Peninsula in Mexico, scientists have discovered a massive annular structure called the Chicxulub crater, which has a diameter of about 180 kilometers and is one of the largest impact craters on Earth. According to the dating of the crater, it was formed at a time that coincided with the extinction of the dinosaurs, so it is likely that the impact event of this crater caused the extinction of the dinosaurs.
Chipped-glass. In the boundary layer of the extinction of the dinosaurs, scientists have also found a large amount of detrital glass, which was formed by the high temperature and pressure generated by the asteroid impact, which melted and splashed the rock into the air and then cooled it. The wide distribution of these debris glasses indicates that the impact of the impact event was significant.
Volcanic eruptions. The impact of an asteroid hitting the Earth is so strong that it can trigger ** and volcanic eruptions on a global scale. In the Deccan Plateau of India, scientists have discovered a large number of basalt flows that were formed as a result of volcanic eruptions, and they also formed at a time similar to the extinction of the dinosaurs. Volcanic eruptions release large amounts of dust and gases, such as sulfur dioxide and carbon dioxide, which can have a serious impact on the earth's climate and ecology.
The event of an asteroid hitting the Earth can be said to be the largest disaster in the history of the Earth, and its consequences are catastrophic, mainly the following:
Global fires. When an asteroid hits, it produces the equivalent of 10 billion tons of TNT, which is thousands of times more than all the world's cores combined. This energy evaporates everything near the point of impact, and at the same time, the debris and ejecta of the impactor will fly into the air at high velocity before falling back to the ground, forming a huge fireball that will cause a global fire. Fires burn away a lot of vegetation and animals, and at the same time, they also produce a lot of smoke and dust, blocking sunlight and lowering the surface temperature.
Tsunami. The site of the asteroid impact is in the ocean, so the impact can trigger a huge tsunami that can reach up to 300 meters and reach speeds of more than 1,000 kilometers per hour. Tsunamis sweep across coastal land, destroying all buildings and life, and at the same time, tsunamis sweep seawater and sediment from the seafloor into the atmosphere, creating a phenomenon called "sea fog". Sea fog can block out sunlight and cause temperatures to plummet, affecting ecosystems and human survival.
Ice age. After an asteroid hits Earth, a large amount of soot and gas blocks out sunlight, causing the temperature of the Earth's surface to drop dramatically for years or even decades. Such low temperatures can lead to the expansion of glaciers, forming ice ages. During the Ice Age, most of the land was covered with snow and ice, making it impossible for plants to grow, animals to find food, and the living environment to be extremely harsh.
Acid rain. After an asteroid hits the Earth, large amounts of sulfur dioxide, nitrogen oxides and other gases will enter the atmosphere and react with water vapor to form acidic substances such as sulfuric acid and nitric acid. These acids fall to the ground with precipitation, forming acid rain. Acid rain can wreak havoc on plants, animals and rocks, reduce the pH of soil and water, and affect the growth and reproduction of organisms.
Oxygen is reduced. After an asteroid hits the Earth, a large number of plants are burned or frozen to death, unable to photosynthesize, and at the same time, a large number of fires and volcanic eruptions consume a large amount of oxygen, causing a sharp drop in the oxygen content in the atmosphere. The decrease in oxygen makes it impossible for many organisms to breathe, especially those that are large and have high metabolisms, such as dinosaurs. The reduction in oxygen also affects the ozone layer of the atmosphere, allowing more ultraviolet rays to penetrate and cause radiation damage to living organisms.
These are some of the main consequences of asteroid impacts on Earth, which together caused the mass extinction of life on Earth, most of which was the dinosaurs. According to the fossil record, the diversity of dinosaurs declined dramatically at the end of the Cretaceous period, and eventually only the bird branch survived. So why did birds survive the catastrophe of dinosaur extinction?
The catastrophe of the extinction of the dinosaurs did not lead to the extinction of all living things, in fact, there are some creatures that survived the catastrophe and thrived in the Cenozoic Era, such as birds, crocodiles, mammals, etc. What are the characteristics of these creatures?Scientists believe that the following points may be the advantages of survivors:
Small size. Smaller organisms have lower energy requirements, easier access to food and hiding places, more tolerant of low temperatures and low oxygen conditions, and better at escaping predators and disasters. As a result, smaller creatures are more likely to survive the catastrophe of dinosaur extinction. This also explains why birds survived, as birds were the smallest of the dinosaurs, and they also had the ability to fly and quickly escape from dangerous places.
Habits. Habits are also an important factor affecting the survival of organisms, and the habits of some organisms make them better adapted to the environment of the extinction of dinosaurs. For example, crocodiles are a class of reptiles that live in water, they have a low metabolic rate, can go without food for long periods of time, and can also dive underwater to avoid the effects of fires and acid rain. As a result, crocodiles were able to survive the catastrophe of the extinction of the dinosaurs. Another example is mammals, which are a group of land-dwelling animals that have a strong ability to regulate their body temperature and adapt to low temperatures, as well as fur and subcutaneous fat, which keep them warm and store energy. In addition, mammals also have some special living habits, such as nocturnal, cave-dwelling, ovoviviparity, etc., which are conducive to their survival in the catastrophe of dinosaur extinction.
Eats a wide range of foods. Organisms with a wide range of diets have more food** than organisms with a specific diet, are more adaptable to changes and deficiencies in food, and are more conducive to survival. As a result, creatures that eat a wide range of food are more likely to survive the catastrophe of dinosaur extinction. This also explains why birds survived, as birds were the most widespread type of dinosaur, some were carnivorous, some were herbivorous, some were omnivorous, and some were even scavengers, all of which allowed birds to find food in food-scarce environments.
These are some of the characteristics of the survivors that allowed them to survive the catastrophe of dinosaur extinction and thrive in the Cenozoic Era. Of course, these characteristics are not absolute, nor are they the only ones, and there are some other factors, such as luck, geographical location, genetic variation, etc., that can also affect the survival of organisms. The causes and consequences of the extinction of dinosaurs is a complex question, and scientists are constantly exploring and researching in the hope of unraveling this historical mystery.
Dinosaurs were the most successful creatures in Earth's history, once dominating the land, seas and skies of Earth, but 65 million years ago, they suddenly disappeared, leaving only the bird branch. Why did the dinosaurs go extinct so cleanly?This is a puzzle that has puzzled scientists and the public. This article introduces the asteroid impact theory, the most powerful cause of dinosaur extinction, as well as other possible influencing factors, such as volcanic eruptions, climate change, disease, etc. This article also explains why some creatures, such as birds, crocodiles, mammals, etc., were able to survive the catastrophe of the extinction of the dinosaurs and thrive in the Cenozoic Era.
The extinction of the dinosaurs is an amazing and sad story that tells us how fragile and precious life is, and how tenacious and creative life is, and how resilient and creative life can be, adapting and evolving in various predicaments, producing countless wonderful and beautiful forms. The extinction of dinosaurs also gives us a warning, that is, as a creature on the earth, we humans are not eternal, nor are we invincible, and we may also face various threats and challenges, such as environmental pollution, climate change, biological **, nuclear war, etc. We should cherish our lives, protect our earth, and live in harmony with other creatures to create a better future together.
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