Zhang Yuan carefully observed the so-called tree core, there were some hollow sieves in the middle, and the overall density was much lower than that of steel.

Yamamoto said astonishingly, "These tree hearts are very good materials for the Riley civilization, providing shelter and food...... But it is also a great crisis that destroys the entire ecological chain! ”

He hung a little scrap of wood with a knife and lit it with a lighter.

Suddenly, the entire burning phenomenon produced a faint burst of smoke.

Zhang Yuan covered his nose and smelled a burning smell of burning plastic, thinking thoughtfully.

Everyone smelled it.

"It really looks like plastic."

"What is plastic?"

Zhang Yuan explained: "It is a kind of polymer material brightened from oil, which is very cheap, and was once widely used by the earth's civilization, but after the oil is exhausted, it is useless, and can only switch to a large number of renewable materials." ”

Yamamoto pressed the button again, "Do you smell it?" This type of tree core is a natural polymer material, and its chemical composition is somewhat similar to the plastic widely used on our planet, that is, a very stable chemical. ”

The screen shows an image of a human geographer looking for a fossil vein in a plain area: a large organic mine with reserves of up to 300 million tons!

"Almost all of the components of this organic mine are the heart of the World Tree. Because it has been buried underground for a long time, it has become something similar to coal. It is even better than coal, and the calorific value is higher. ”

Some of the most intelligent biologists have already figured out why Professor Ichiro Yamamoto thinks a mass extinction is about to happen on this planet!

Why?

"Because these tree hearts are actually ...... It can't be broken down by native microorganisms! That's why it's piled up in large quantities. ”

Zhang Yuan was suddenly a little speechless in surprise, human beings were actually able to witness it with their own eyes...... A mass extinction!

The so-called "World Tree" of the Riley people, on this planet, is undoubtedly a very excellent species, providing food and a place to live for the Riley people.

Because of its strong environmental adaptability, the "World Tree" can be found in almost every corner of the planet.

But also because the "heart" of the World Tree is too evolutionarily advanced, so that the native microorganisms are completely unable to decompose this highly stable substance.

A large number of organic veins found by humans on the plains are the original forests, and other fibers have rotted, and only the core of the tree has accumulated and settled in the ground.

Why would this lead to mass extinctions?

Quite simply, because the carbon cycle of the native planet is disrupted.

In the usual case of aerobic respiration, the consumer inhales oxygen and exhales carbon dioxide, and the producer inhales carbon dioxide, producing oxygen, forming a carbon cycle.

But now, a lot of carbon is turned into the heart of the tree and sinks into the ground, which leads to the concentration of carbon dioxide in the atmosphere, which gradually decreases, and plants do not have enough carbon dioxide, and they die in large numbers, and then animals also die in large numbers.

The concentration of carbon dioxide on this planet is about 5 thousandths, millions of years, tens of millions of years, and it may decrease by 60%-80% of carbon dioxide, when it is difficult for plants to reproduce, and it will be truly lethal.

A biologist sitting down asked, "Is there something that native microorganisms can't decompose?" Professor Yamamoto, are you sure that your scientific research is correct? ”

This question is explained by an expert who is personally in charge of the geography expedition: "We have found the active ingredient in the heart of the tree in the soil of the world...... Although these substances are polymer organic substances, they will be turned into some fine fragments due to physical action, but even the decomposition rate of these fragments is extremely slow, and they can exist stably for thousands of years, or even tens of thousands of years. It shows that the decomposer of this planet is indeed unable to effectively decompose the heart of the World Tree. ”

"Well, it's like plastic, small plastic particles, although not poisonous, but buried underground for a long time will not decompose. The active ingredient in the heart of the tree is even more stable than plastic and can last longer. ”

Zhang Yuan nodded.

This is where the Great Crisis comes in.

The expert continued: "Ladies and gentlemen. This kind of environmental mutation due to the evolution of plants has not happened on Earth......"

"2.4 billion years ago, there was a 'great oxygen event' on Earth, a great oxidation event that changed the composition of minerals on Earth and made it possible for animals to emerge in the future."

"That is, the oxygen levels of the whole planet have soared, mainly because of the great evolution of plants, wood fibers began to form, and the fungi that broke down plant fibers have not yet appeared. This has led to a drastic decrease in the concentration of carbon dioxide in the air. ”

"A large amount of carbon was solidified and deposited into the ground along with the life cycle of the plant, so that the Carboniferous period later formed high-quality coal, which benefited the humans born later."

"At the beginning, the earth's decomposer capacity was not strong enough, the proportion of carbon dioxide in the atmosphere decreased, and the proportion of oxygen increased significantly, reaching the highest proportion of atmospheric oxygen in the history of the earth in the late Carboniferous period. The sudden change in the environment, which caused the mass extinction, was followed by the Big Bang. ”

Everyone in this room understands the rhetoric.

"And Riley Star is also in such a special stage, with the accumulation of time, there are more and more dead world trees, and more and more tree hearts are accumulated."

"The planet has been formed for a long time, and the concentration of carbon dioxide in the atmosphere is not too high, so where does the carbon come from? After the carbon dioxide in the atmosphere is consumed, of course, it is the carbon in the living organism...... As long as there are more dead creatures than those who are born, with the destruction of the carbon cycle in the whole world, more and more carbon elements will be buried in the ground! ”

"If there is no carbon dioxide in the atmosphere, there will be fewer and fewer plants, and naturally fewer and fewer animals. Instead, the concentration of oxygen rises.

"The mass extinction, just like that, began!"

"Or rather, the mass extinction has begun, but these Rileys don't know it. Tens of millions of years later, plants and animals are scarce, and a large amount of carbon has become a plastic-like substance...... That's it in theory. ”

Everyone sat quietly in their seats, thinking, thinking.

After the extinction of this creature was nakedly revealed, it was serious and full of heavy killing intent.

Comes from the killing intent of the planet itself.

This kind of killing has always been slow and firm.

Even, as an interstellar civilization, it is difficult for human beings to stop this power that comes from the planet itself.

……

(PS: Without the comments of the stupid dick online game, it feels so passionless to write!)

Especially in the past few days, it is still pushing in strong winds, and it was covered by the big red flag, which led to an unsatisfactory increase in the collection...... Ah, it's unlucky, but it's better to celebrate the third watch! ）

(The National Day military parade is still quite spectacular, and the testimonial will not be published, I like the DF41 nuclear bomb the most, although it can't be used in war, but having this thing means real safety!) ）