It has been 4.6 billion years since the earth was born, and it has gone through Archean, Proterozoic, Paleozoic, Mesozoic and Cenozoic. Geological time is usually measured in millions of years, which is a very abstract concept for ordinary people. In order to briefly introduce the evolution process since the birth of the earth, we condensed the history of the earth for 4.6 billion years into one day, that is, 24 hours, and watched the evolution of the earth in a long scroll with familiar time scales.
The earth was born 4.6 billion years ago, which is the starting point, and 24 hours a day is zero. The period from 4.6 billion years ago to 3.9 billion years ago is the birth period of the earth, which translates from 0: 00 to 3: 39. When the earth was born, the original ocean began to form, and simple organic matter was produced in the ocean, which was the premise of the birth of primitive life. In the 24-hour history, the birth of the earth took 3 hours and 39 minutes.
After the earth was formed 3.9 billion years ago, it entered the second geological era-Archean. From 3.5 billion years ago to/kloc-0.5 billion years ago, that is, from 5: 43 to 16: 09, the earth was in Archean. According to the present day, from 5: 43 in the morning, it was just dawn-until 4: 09 in the afternoon, the sun began to set in the west, and the earth was in Archean almost all day. During this period, the earth was in a high temperature climate, with strong volcanic activity and strong solar radiation, prokaryotes appeared and primitive life appeared on the earth.
65.438+05 billion years ago, that is, 65.438+06: 09, the earth entered Proterozoic, and Proterozoic ended 570 million years ago, that is, 26.5438+0. The lighting of the earth is in Proterozoic from afternoon to evening to darkness. In Proterozoic, eukaryotes, multicellular algae and lower invertebrates appeared, the earth's temperature began to drop, volcanic activity decreased and the ocean area increased.
570 million years ago, 2l, the earth entered the Paleozoic era, ending 2.248 billion years ago at 22: 40. Paleozoic is divided into Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.
In CAMBRIAN (from 570 million to 550 million years ago), from 2 1 to 2 1: 20, macroalgae began to appear and the climate was mild.
The Ordovician (505 million years ago to 438 million years ago), that is, 2 1: 20 to 265, 438+0: 465, 438+0: 265, 438+0, was the heyday of invertebrates, with warm climate and continuous expansion of ocean area. At 2 1: 4 1: 00, the first extinction occurred on the earth, that is, the Ordovician extinction. Extinction flash was a large-scale ice age at the end of Ordovician, covering Africa, South America and Europe today. Due to the cold climate and the drop of sea level, 85% of invertebrates living in water became extinct.
During the Silurian period (438 million to 480 million years ago), that is, from 2 1: 4 1 to 2 1: 50, naked ferns and terrestrial arthropods appeared.
Devonian (from 408 million years ago to 360 million years ago), that is, from 265,438+0: 50 to 22: 05, this 65,438+05 minutes is a negative cycle, and many new species appeared, such as Lycopodium, Equisetum, Pteris, Amphibia and wingless insects. Silurian and Devonian were dry and hot, and the ocean began to retreat. At 22: 05, the second extinction occurred, and marine life suffered extinction, also because of the cold climate and the reduction of ocean area.
The Carboniferous period (from 360 million years ago to 286 million years ago), that is, from 22: 05 to 22: 28, was the heyday of amphibians, and giant winged insects began to appear, with a mild and humid climate and frequent orogeny.
Permian (from 286 million years ago to 248 million years ago), that is, from 22: 28 to 22: 40, the climate was dry and hot, the crust was folded and orogeny was frequent. At 22: 40, the third extinction occurred, and more than 95% of the creatures were extinct. This extinction made the main organisms occupying the ocean for nearly 300 million years disappear, giving way to new species and completely renewing the ecosystem, paving the way for the evolution of reptiles such as dinosaurs. The scientific community generally believes that this extinction is a milestone in the transition of the earth's history from Paleozoic to Mesozoic.
From 2 1 to 22: 40, the Paleozoic lasts 1 hour for 40 minutes, which is the peak of invertebrates. Fish, amphibians and reptiles began to appear, and green plants began to appear.
248 million years ago to 65 million years ago, that is, from 22: 40 to 2: 00 > >;
Question 2: How long have humans appeared on the earth? It originated in Africa about 2 million years ago. At present, the earliest human being found in the world is called homo habilis, and the guy with the earliest fossil sample is named "Jesse".
In China, the earliest human was Yuanmou ape-man 6.5438+0.7 million years ago, in today's Yuanmou County, Yunnan Province; Followed by Lantian people in the Yellow River Basin.
Question 3: When did the earliest human beings appear? At present, it is generally believed in academic circles that the time when ancient apes turned into human ancestors was 7 million years ago.
Judging from the discovered human fossils, human evolution can be roughly divided into the following four stages:
(1) Australopithecus stage. The discovered Australopithecus lived 4.4 million years ago to 1 10,000 years ago. According to the study on the anatomical characteristics of fossils, the most important feature of Australopithecus is that it can walk upright on two feet.
(2) capable people. 1960 homo habilis fossils were found in Tanzania and Kenya in East Africa. The earliest homo habilis existed19 million years ago. Homo habilis belongs to homo habilis. The brains of homo habilis are bigger than those of Australopithecus.
(3) Homo erectus. Homo erectus belongs to Homo erectus in classification, referred to as Homo erectus, commonly known as Homo erectus. Homo erectus fossils were first discovered in Java, Indonesia in 189 1. There was an argument about whether it was a man or an ape. It was not until the 1920s that Peking man fossils and stone tools were discovered in Zhoukoudian, Beijing. Established the position of Homo erectus in the history of human evolution. Homo erectus lived about 6.5438+0.7 million years ago to over 200,000 years ago. So far, homo erectus fossils have been found in Asia, Africa and Europe.
(4) Homo sapiens is generally divided into early homo sapiens (ancient homo sapiens) and late homo sapiens (modern homo sapiens). Early Homo sapiens lived from 200,000 years ago to 65,438+million years ago. The survival of late Homo sapiens began about 65,438+million years ago. Its anatomical structure is basically similar to that of modern people, so it is also called modern people in anatomical structure. Australopithecus is the earliest known human. When asked about the earliest human beings in the world, in which country and how many years ago, there are two answers. One is that it is in Africa, and it may make Central Africa. This is the view of the majority of the academic circles in the world now.
Another way of saying it is in the Yangtze River valley of China. This view can often be found in China's science and education content. Objectively speaking, so far, it really cannot be ruled out that human beings originated in the Yangtze River basin. Ask three questions: Where were the earliest humans in the world? How many years ago did they live? Do you think there was a country at that time?
Australopithecus in central Africa was 7 million years ago. Hehe, too. I mainly know what and where the earliest humans were. The answer to Australopithecus was 7 million years ago.
Question 4: When did humans first appear? The earliest ape-man fossil found in the world is the Javanese ape-man found in Java, Indonesia189/kloc-0 years ago, ranging from 600,000 to 800,000 years ago. 1927 The Javanese ape-man and Peking ape-man discovered in Zhoukoudian, China, were once recognized as the "earliest" humans in the world. At that time, people thought that the history of human beings did not exceed 654.38 million+years, and Asia was the first place where human beings appeared. Shandong Yiyuan ape-man 198 1 discovered by China belongs to the same era as Peking ape-man. However, this theory of the earliest origin of human beings was overturned by two archaeological discoveries in China. After liberation, archaeologists discovered ape-man fossils in Lantian, Shaanxi and Yuanmou, Yunnan. Lantian ape-man was 6.5438+0 million years ago, and Yuanmou ape-man was 6.5438+0.7 million years ago.
So, how long is the history of mankind? In the past twenty or thirty years, archaeologists have found many fossils of ape-man on the African continent, which has given us a new understanding of human history. 1959, an almost complete ape-man skull fossil and labor tool was found in Tanzania, dating from1750,000 years ago. 1972, ape-man skulls, leg bones and stone tools were found in Kenya, 2.6 million years ago. 1973 It was reported that hominid fossils found in Ethiopia were about 3 million years ago or 3 million years ago. From this perspective, human history is not 800,000 years, nor 1.7 million years, but more than 3 million years. As for the place where humans first appeared, more archaeological discoveries are needed to determine.