Human origin From fish, the friend who is eating fish put down the chopsticks in his hand, saying that is he eating his ancestors?
fish can be eaten with confidence. Now the fish on the earth have completely parted ways with us. They are not our ancestors, but they only have common ancestors with us.
Is the braised fish we eat our ancestors?
How many years have it been since I went from a fish to a human? How did limbs evolve?
Let's turn our time back to the oceans more than 400 million years ago to see how all the ancestors of vertebrates evolved.
4 billion years ago ocean
ancient fish
Chinese Academy of Sciences paleontology published a paper in the journal Nature, which describes the discovered
No matter what kind of vertebrate it is, it has a mandible. How did this structure come about has always been a mystery.
Because between the most critical .44 billion years and 410 million years, lacks corresponding fossil data , as if vertebrates suddenly grow their mouths.
The ancient fish discovered by the Chinese Academy of Sciences this time lived 1.436 billion years ago and 439 million years ago . can just fill the gap in fossils .
Judging from the restoration diagram, these ancient fishes in already have all the characteristics of today's fish . So can it be said that fish have not evolved in more than 400 million years?
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The three existing fish species on Earth are: radial fin fish, cartilage fish and fermented fin fish .
Radifin fish is the fish with the most species . The number of radial fin fish species discovered by humans is more than 20,000. Most of the fish referred to in today are actually radial fin fish , representing the species four big fish , carp crucian carp.
, as the name suggests, its spine is not what we think of as bones, but is more inclined to soft tissue structure. Although their bones are soft, this family has produced a famous "tough guy" - sharks.
Today's sharks, rays, and other fish are cartilage fish . Although their species cannot keep up with the radial fin fish, the ecological niche of cartilage fish is generally higher than that of radial fin fish.
cartilage fish and radial fin fish
meat fin fish, we can basically no longer see it. There are only two types of meat fin fish left now, one is living fossil speartail fish from South Africa, and the other is lung fish from Africa.
However, the meat-finned fish is the closest fish to us. It has a common ancestor with all vertebrates today. Among them, lung fish is the intermediate state of the fish's landing process that year, and they evolved into the lungs.
So What we eat fish is not our ancestor , at most we count our far away from .
Live fossil speartail
Fish get ashore
If you throw a fish on the shore today, it will die soon.
Fish cannot do without water . Even the cetacean , which looks like a fish but is actually a mammal, cannot leave water.
But when Divonian , the meat-finned fish said, "I don't want to go ashore, I'm going to go ashore!"
meat-finned fish, the name is very intuitive at first glance. fish fin has meat on it. Today we can find that their fins are a row of long thorns and there is no meat, so the one who goes ashore in is not the radial finned fish .
Meat-fin fish fossil
There have been fans who pretend to be shark fins on the market, which shows that sharks are not meat-fin fish .
There is meat on the pectoral fin of the meat fin. At first, there was no bones inside , but one thing changed the life of the meat fin.
There is also a group called shield skin fish . They have become extinct, but they have left an important mark in the history of biological evolution.
The first overlord in vertebrate history - Dun's fish , which is from the Shield Fish family. It was from it that all the overlords of the earth after that were vertebrates.
The first generation of vertebrate overlords - Dung's fish
Dung's fish ruled the Devonian ocean . It was a cruel overlord. It not only swept the arthropod and mollusk at that time, but also did not let go, even the radial fin fish, cartilage fish and meat fin fish of its own family.
Radiated fin fish started to swell from this time, and when it was at the bottom of the food chain, it has been like this for more than 300 million years since then. Occasionally, one or two fierce characters are just a flash in the pan.
Although the name of the cartilage fish is "soft", it has a very strong personality. They want to replace the shield fish, so evolved into shark .
The shark became this cruel look today, with more or less credit to the shield-skinned fish inside.
Devonian Shark
The position of the meat-finned fish is a bit embarrassing. If you are not convinced, you will not be able to do it. If you are forced to do it, you will simply leave the ocean and go to the relatively barren freshwater at the time.
The freshwater area at that time was desolate, with too little food inside. As early as more than 400 million years ago, plants and some arthropods came ashore, and they formed a sparse terrestrial ecology .
Meat-finned fish can temporarily leave the water every time they eat, and climb to the shore to eat some plants or insects.
Their The pectoral fins with flesh can help them move better on land and can also help them return to the water, but there can also be accidents, such as insufficient strength of the pectoral fins lead to sudden death on the shore.
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They have been on the shore longer and longer. From the initial shore to the real shore, before they knew it, the pectoral fin has become a bone that can support their body .
In addition to pectoral fins, the anal fins of meat-finned fish also began to harden , and bones also grew inside. The fish during this period were called quadruped fish , and the prototype of the limbs was formed.
quadruped fish
and in order to solve their breathing when they get ashore, their Their fish bladder began to evolve into lung , which can breathe air directly, so there is no longer the need for fish gills.
At the end of the Devonian period, the earth of ushered in a wave of great hypoxia . The shield-skinned fish in the ocean became extinct, and the cartilage fish was also hit hard. The radial-finned fish continued to stay in the low ecological niche.
This wave of hypoxia mainly occurs in water. meat-finned fish no longer rely on the oxygen in water , but directly breathes air . They successfully survived the mass extinction at the end of the Devonian period and entered the next prosperity.
Meat-finned fish: I got ashore
ushered in prosperity
After the Devonian period, the earth entered the Carboniferous period , and quadruped fish began to evolve into amphibians . Although they can live without water, they cannot leave for too long, and they still have to rely on water to reproduce.
, and during this period, a group of amphibians returned to the ocean, such as sea ant , which are all amphibians anyway. Is there any difference between living in seawater and freshwater?
So the Carboniferous period became an era of amphibian reproduction, and many overlords emerged.
However, it should be noted that most of the amphibians such as are not our ancestors . Only those with five fingers are there, and the number of other fingers is not.
Amphibians of Carboniferous period
During this period, many amphibians had not yet fully formed the spine of them, so they are called vertebral amphibians .
Our true ancestors did not have any advantage in this amphibious competition, but were a little passive. Therefore, our ancestors decided to stay away from the group of big-mouthed monsters in the water, and entered the inland , where few animals were still on the way.
In order to prevent itself from losing water, the skin of 's ancestors began to thicken and secrete special ester substances to prevent the evaporation of water. The four feet of also began to become slender , and the belly no longer squirmed against the ground.
Existing amphibian
About 340 million years ago, a vertebrate , the ancestor of single bow beast , appeared. It looks a bit similar to a lizard, but it is the ancestor of future mammals .
But at the same time, an animal called forest lizard was also born. Among its descendants, a family called dinosaurs will be born, which will rule the earth for 160 million years.
Carboniferous period is also a period of plant prosperity. The land on Earth was dyed green for the first time, and most of these plants became our coal today.
Carboniferous rainforest
The road of evolution
From the birth of fish to humans, has spanned more than 400 million years of history . If chordokane , the predecessor of vertebrate, is included, then this evolutionary path has spanned more than 500 million years of history.
Humans did not suddenly appear. Humans were apes before, monkeys before, monkeys were arborized mammals that looked like rat , and further forward, there were even stranger-looking holographic animals that looked like lizards.
Every animal on the earth can trace the origin and find its starting point . In the end, all living things on the earth have found a common ancestor. is the first life on the earth - Luka . Luka laid the foundation for the form of the earth's organisms - cell structure .
Erluka was born 3.8 billion years ago, and the earth was only 800 million years old at this time.
The beginning of life
Life is so magical. The earth spent about 3.8 billion to give birth to intelligent life like humans. Is it accidental or inevitable?
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