Ancient creatures, both animals and plants, were much larger than they are now, why?

When you look at some things like Godzilla and King Kong, have you ever thought about why prehistoric creatures are basically huge! Now the creatures on land are not as big and tall as they used to be?

The first is the difference in temperature!

Take dinosaurs as an example, dinosaurs are cold-blooded animals, and the size of cold-blooded is directly proportional to the temperature at that time, in prehistoric times, scientists have found that the atmosphere at that time was not as thick as it is now, and the sun is stronger than the energy that shines on the earth now, and the temperature is relatively high. At that time, the earth was all tropical rainforests, and food was abundant. You don't have to worry about food at all!

This is followed by a change in oxygen concentration!

In ancient times, the climate was warm and humid, the forest cover was much higher than it is now, the plants were abundant and lush, and the plants were the foundation of the ecosystem, so the oxygen content was also high! Nowadays, animals are generally smaller, which means that the oxygen content is lower.

Adequate oxygen is also necessary for the growth of large organisms, and if the dinosaurs were pulled to this environment, it is estimated that they would have suffocated to death due to low oxygen levels.

At present, the largest creature on the earth is the blue whale, in fact, the oxygen demand of aquatic organisms and terrestrial organisms is different, so some creatures in the sea are represented by blue whales, and their size is still relatively large compared to land organisms! However, the life in the sea has also been reduced from prehistoric times due to temperature and climate change, so the blue whale is the largest animal ever seen on the earth, and it is said that the blue whale can break the elephant's head with a flick of its tail!!

Finally, their own genes are different!

The genes of prehistoric dinosaurs were not as complete as they are now, and the animals of the dinosaur era lacked reproductive genes in their bodies that inhibit cell growth. Many creatures in ancient times did not have this gene, so their size increased uncontrollably, and the current blue whale does not have this gene.

Just like the current crocodiles and dinosaurs belong to the same era, as long as the crocodile does not die, the body cells have been growing, but because of various factors such as temperature, oxygen content, etc., the crocodile is not as big as prehistoric.

In recent centuries, human indiscriminate hunting and killing have also targeted more tall animals, most of the large animals have been subjected to varying degrees of distribution retreat and population decline, and now the speed of animal extinction is comparable to the speed of five prehistoric mass extinctions!

Because now that technology is developed, the amount of exercise has decreased, so it has become smaller.

Because at that time, the oxygen content of the earth's atmosphere was much higher than it is now, and the high oxygen content would grow huge plants, and animals would evolve to great exaggerations because of enough oxygen.

In ancient times, the oxygen content of the Earth's atmosphere was higher than in modern times, which made the organisms of that time larger.

Why were organisms so large in ancient times? What factors does this have to do with this? As for the topic of why animals were very large in ancient times, I personally believe that the survival of organisms on the earth has always had its evolutionary and development of the phased phenomenon, the so-called phased phenomenon refers to the period of time between major natural disasters (such as planets hitting the earth) that cause the death of most species on the earth at the same time, that is, the time between the last impact of the planet on the earth and the next planet impact on the earth is a stage of biological evolutionary development.

As early as 70 million years ago, in the late stage of the last stage of biological development, there was a hegemonic species of the age of dinosaurs, its individual size was huge, and the reason for its extinction, most scientists believe that it was caused by the major natural disaster phenomenon of planets hitting the earth, and then there will be today's stage of human survival and development, the development stage of today's biology has gone through about 70 million years, and has evolved intelligent human beings and large-sized animal species such as whales and elephants.

With the continuous passage of time and the continuous evolution of animal species, the individuals of animal species will appear larger and larger, and the further back of this stage of development, the larger the body of the animal individual will be, and at the end of this stage of development, the huge body of the animal species is the peak of the biological development stage.

Therefore, the small species that have survived in each stage of biological development are easy to be oxidized and disappear, and the bones of larger animals are easy to be preserved by nature. Therefore, at present, most of the animal individuals found in ancient times are large-sized, which may be the traces left by large-sized animal species in the later stage of the previous biological development stage, I don't know whether this is accurate.

Because the living environment in ancient times was relatively simple, the environment was relatively good, there were very few natural disasters, and the ecological food chain was relatively sound, so the size of the creatures was very large.

Because the earth's environment at that time was relatively good, with plenty of oxygen and food, they were relatively large. This is a very big change from the earth's environment.

At that time, the environment was very suitable for the development of these animals, and it was so large. Environmental reasons, temperature reasons, food reasons.

Ancient creatures are not all huge, but compared with existing creatures, there were some huge animals living in ancient times, the most typical being dinosaurs and so on. Scientists believe that some huge animals existed in ancient times because the earth's environment and climate were better than they are now before hundreds of millions of years ago, and it was suitable for animals to evolve in the direction of large-scale. For example, from the early Triassic period to the late Jurassic period 100 million years ago, the earth's climate was warm and humid, and the four seasons were not distinct, which provided abundant food for various animals and made the oxygen content in the earth's atmosphere reach about 25 percent.

After entering the Cretaceous period, the earth's climate changed dramatically, the change of atmospheric circulation reduced precipitation, dense forests disappeared, grasslands replaced forests, large areas of land desertification, average temperature decreased, and atmospheric oxygen content also decreased. A series of changes have drastically reduced the variety and number of large organisms. At the end of the Cretaceous period, an asteroid hit the Earth 65 million years ago, dealing the final and fatal blow to the large organisms, and almost all the large organisms were extinct.

Since then, the Earth's climate has never returned to the level of 100 million years ago, and large organisms have not evolved again.

First of all, plants are also divided into annual and perennial plants, and not all organisms live longer than animals. Second, although they all belong to living things, the physiological system of animals is much more complex than that of plants, and the physiology of animals must be precisely regulated by nerves and hormones. Third, the survival of animals depends on food, oxygen and water, which is very dependent, once these elements are lacking, it will affect the operation of the entire physiological system, and eventually lead to death; Although plants also need oxygen for respiration, they also need some necessary elements in the soil, but they are not as dependent on the external environment and substances as animals, and can tolerate them for a longer time under extreme conditions.

Because plants have very low requirements for the environment, plants can survive in very harsh places, but animals have very high requirements for survival, and must have clean water and enough food, so the range of life is relatively small.

Because plants are not so demanding on the environment in which they grow, and the nutrients they need to absorb are very easy to find.

Big and not big are relative, in fact, the creatures are too small now.

When you grow older, you have to eat more food to sustain life, in ancient times, food was quite sufficient, but after several mass extinctions, food was scarce, and tall creatures starved to death, and for those small mammals, a little food was enough, so small mammals survived, and other mammals that evolved since then were relatively small.

At that time, gravity was small and so large, and astronauts became higher in space.

There were many giant species in the age of dinosaurs, and even giant dinosaurs such as the fragile dinosaur were close to the size of the blue whale, which is quite remarkable on land, and there have been giant insects in the history of the earth, but they are not very common.

From the perspective of biological evolution, the best is the one that can adapt to the environment, and the diversity of species on the earth has created the difference in the size of the earth's organisms.

Why are animals getting smaller and smaller? According to scientists' research, this is related to the oxygen content in the air, and the oxygen content in the air today is 21%. In ancient times, the vegetation was lush and untouched, and the air contained 20% more oxygen than it does now.

So, at that time, centipedes were one meter long, dragonfly wings were also one meter wide, and dinosaurs could grow up to 25 meters long.

As far as giant dinosaurs are concerned, they live in a long era with a relatively stable environment, and the earth's land and marine plants are quite lush in a long period of time, so that the earth's organisms can produce a lot of organic matter and fix a large amount of sunlight energy, and the prosperity of the earth's organisms makes the creatures not lack food, and the number of species can produce more mutant genes.

At the same time, the weak eat the strong, and the small size means a greater survival risk, and it is easy to become the food of other predators, so natural selection, the size of the animal is getting bigger and bigger.

Later, the living environment of the earth deteriorated dramatically, and the large animals could not find food, and gradually became extinct, leaving only very small or low-level animals and plants, so that the size of the animals changed from large to small.

In recent millions of years, with the rise of apes, the emergence of more intelligent creatures has further crowded out the living space of other large animals, resulting in the extinction of animals such as thylacine and West African lion.

Like the rats in recent years, in order to adapt to today's high-rise buildings and the thin seams of each door, the rats have become smaller from fat to smaller, as small as one or two heavy!

Because the amount of oxygen in the air decreased, the surrounding environment in ancient times was a hyperaerobic environment, and the photosynthesis of plants would cause it to inhale more oxygen, thus evolving into a larger body size. The same is true for animals, where the nitrox environment increases oxygen consumption, making the musculoskeletal muscles bigger and stronger.

Because in ancient times, the oxygen content of the earth was very high, and the high oxygen content would cause plants to grow very large, and animals would evolve to be very large, but then experienced a mass extinction of life 65 million years ago, and only small animals and plants survived.

Because scientists have studied that the air composition of the surface in ancient times is different from that of today's air, the proportion of oxygen in the air in ancient times was the largest, which made ancient animals and plants grow fast and have large individuals, and now the proportion of oxygen is small and small.

When I talk about ancient times, I am talking about the age of dinosaurs, when the size of animals and plants on the earth was indeed very large, not only dinosaurs, but also many ferns were much taller than now, and even small insects such as mosquitoes and flies were 2 to 3 times larger than today. But it's safe to say that they're not caused by the destruction of mutations by radioactive materials, and I think there are three main reasons why they've grown so big.

At the beginning of the dinosaur era, the animals and plants on the earth began to develop towards large-scale, not only dinosaurs, and radioactive element alteration genes could not change the genes of all species, and geologists did not find radioactive elements in the strata with dinosaur fossils, nor did they find strata with radioactive elements, so there should be little relationship between them.

The first reason is that the climate and ecological environment are good.

At that time, the animals and plants grew very big, the main reason is that the ecological environment of the earth is very good, it can be said that it is much better than now, in the nearly 200 million years from the appearance of the dinosaurs to extinction, the climate on the earth is relatively warm and humid, the plants grow lush and lush, good growth conditions, so that plants can grow very big, and the habitat of animals is much larger than now, because of the abundant food, animals have no risk of nutritional deficiency, so animals can also grow very big.

The second reason is that the oxygen content in the Earth's atmosphere was relatively high at that time.

Scientists believe that the oxygen content in the atmosphere should have exceeded 30% at that time, which is 1 3 more than now, and in the oxygen-rich ecological environment, the bodies of animals and plants grow and develop relatively quickly, so the volume is correspondingly large, especially for small animals such as insects, which are 2 to 3 times the volume of the same species now.

The third reason is that some animals do not have inhibition of growth genes.

This is mainly for large animals, such as dinosaurs, the main reason why they grow so big is because they do not form genes that inhibit the growth of the body, so they grow all their lives, which is why the older the dinosaurs tend to be.