How much do you know about earth? Many of the basics about Earth aren't very complicated, but there are plenty of little-known details about the planet's story that deserve attention.
Andrew Knoll, a professor of natural history at Harvard University, has compiled 6 basic but little-known facts about Earth that may shed some light.
Earth is a planet that records its own history.
Grand canyon. (Photo: Murray Foubister, Wikimedia Commons, CC BY-SA)
The rocks of the earth are like a thick book, and each page of it is like every strata, recording different physical, chemical and biological imprints that detail what the world has looked like at different times in earth's history.
Take, for example, the famous Grand Canyon of the United States, which is not only magnificent, it is also a huge natural library, and each layer of rock has its own legend. The rocks at the bottom of the canyon tell the story of about 800 million years ago, when oxygen was already present in the atmosphere, but it may not have been enough to oxidize the oceans. Above these rocks are rocks from 500 million years ago, which record the emergence of terrestrial creatures.
When the history of the earth has turned over 85%,
Animals appear.
trilobite. (Photo: Rept0n1x, Wikimedia Commons, CC BY-SA)
Whether it's humans or dinosaurs, or even trilobites, all animals are in a sense "late" for a party on Earth. The reason is that for most of the history of life on Earth, it has been the world of microorganisms.
For billions of years, bacteria and other single-celled organisms were the only life on Earth. In fact, if you count from the first dinosaurs, until today, this period of time accounts for only about 5% of the history of life on Earth. Those microscopic life forms not only dominated the planet for a long time, but also really transformed the planet. For example, cyanobacteria ingest carbon dioxide and release oxygen. About billions of years ago, they began to produce more oxygen than the Earth's natural processes consumed, allowing oxygen to begin to accumulate in the atmosphere, paving the way for the arrival of animals in the future.
Air, sea, continent and the possibility of life
They were all arranged at the time of the birth of the earth.
Imagining a picture by artists of the forming solar system. (Photo:NASA)
Professor Knoll believes that there is a good chance that Mars and other planets will never be like Earth, because these planets may lack suitable components from the beginning. Instead, when our solar system formed, the Earth got all the ingredients it needed and eventually transformed into a giant "blue paradise" after a series of opportunities.
For almost the first half of our planet's history,
Oxygen is largely absent in the air and oceans.
A very different planet. (Photo/UCL)
Modern life is bathed in an atmosphere rich in oxygen. It's easy to think that life can't exist without oxygen, but that's not true.
If we go back to the ancient microbial world, there was a lot of life on Earth in the early days, which survived for billions of years without oxygen, or with very low oxygen levels.
The modern Earth does not necessarily represent our planet,
Because it has been changing over time.
The Earth in Development. (Photo: Pablo Carlos Budassi, Wikimedia Commons, CC BY-SA)
The Earth is a dynamic system that is constantly changing, and of course, this change is measured on geological timescales of billions or millions of years.
For example, in the Cambrian Period 500 million years ago, there were supercontinents on Earth, and North America and Northern Europe were put together, and all the southern continents were clustered into one. We humans actually live at a special moment in the history of the earth, which is the climax of the development of all previous stories.
But what will the planet look like 500 million years from today? Can we still recognize it? These are still unknowns.
In the history of the Earth, the high rate of environmental change
Usually coincides with a high rate of extinction.
This statement clearly does not bode well. Professor Knoll points out that today, our planet is changing at a rate rarely observed in the geological record. Since the 1950s, the amount of carbon dioxide in the atmosphere has increased by nearly 30 percent. Global warming, ocean acidification, affects many species and reduces oxygen levels in the deep-sea environment.
But don't forget, about 252 million years ago, massive volcanic activity drove similarly intense and rapid environmental change, wiping out the vast majority of animal species on Earth and triggering swarm extinction events. Knoll argues that whether the Anthropocene will also end in a swarm extinction depends on how we act.
#创作团队:
Compile: M ka
Typography: Wenwen
#参考来源:
https://news.harvard.edu/gazette/story/2022/04/interesting-facts-about-earth-from-harvard-paleontologist/
https://www.ucl.ac.uk/earth-sciences/news/2015/dec/life-exploded-earth-after-slow-rise-oxygen
#图片来源:
Cover image: pixnio
首图：Yuri Samoilov, Wikimedia Commons, CC BY