As written by livescience.com, our evolutionary history shows that many major adaptations – not only the mind but also the more complex animal and cell forms, photosynthesis and life itself – are extraordinary events that occur once. Therefore, they are also very unlikely. Our evolution can be compared to winning the lottery, only evolution is a very unlikely event.
The universe is vast – just out of reach. Bird Take contains more than one hundred billion stars, and there are more than one trillion galaxies in visible parts of the universe, tiny particles of the universe that we have reviewed.
Although the inhabited world is sparse, their enormous numbers – from planets to as many stars, and perhaps more – indicate that there is a lot of life there. So where is everyone? This is called the Fermi paradox. Always big and old, with enough time and space for intelligence development, but there is no evidence of that.
Could his intelligence not develop at all? Unfortunately, we don't have the opportunity to explore extraterrestrial life to answer this question. However, we can look at the history of the Earth around 4.5 billion years to see where evolution repeats and where it doesn't.
Sometimes evolution takes place – different species are close together for the same result. And if evolution is repeated often, it might make sense or even be inevitable.
There are impressive examples of what is called convergent evolution. Suppose the extinct Sterling wolf, which lives in Australia, has a kangaroo that is similar to a wolf, but in all other respects it looks like a wolf, although it evolved from other mammal groups. Other cases are Sterling moles, Sterling ants and Sterling flying squirrels. Interestingly, the whole history of Australian evolution, when mammals began to acquire different traits after the disappearance of dinosaurs, was reflected on other continents.
Other spectacular cases of convergent evolution include extinct dolphins and ichthyosaurs, which have acquired forms similar to floating in water, as well as birds, bats and pterosaurs, simultaneously mastering the ability to fly.
Convergence can also be observed for each organ. Not only vertebrates, but also arthropods, octopus, worms, jellyfish have developed their eyes. Vertebrates, arthropods, octopuses and worms also have different noses. The feet have evolved convergently in arthropods, octopus, and four types of fish (walleye, clownfish, skate, and stingray).
However, important nuances need attention. All of these animals, touched by convergent evolution, belong to the true multicellular family (Eumetazoa). True multicellular animals are complex animals with symmetry, mouth, intestine, muscles, and nervous system. Different true multicells find solutions that are similar to the same problem, but the complexity of the body that makes it possible is unique. Complex animals evolved only once in history, showing that they could not have developed.
Strangely, many of the major events in evolutionary history are unique and may not be possible. One such case is the development of vertebrate skeletal bones that allow large animals to move ashore.
Complex eukaryotic cells, which consist of all plants and animals that contain nucleus and mitochondria, only develop once. Gender specific differences only develop once. One-time events are also photosynthesis, which increases the amount of life energy and produces oxygen. This one-time event can be linked to human-level intelligence. There are sterling wolves and sterling moles, but there are no sterling humans.
For some people, evolution is repeated, and some are not. If we only see evolutionary convergence, the resulting image will be distorted. Convergence seems to be the rule and our evolution is possible. But if we look for examples of non-corrective evolution, there will be many, and fundamental events, complex adaptation cases, seem to be the least recurring and therefore the least likely.
In addition, these events are interdependent. Humans cannot evolve until fish bones have developed, allowing them to creep to land. Bones cannot develop until complicated multicellular animals appear. Complex multicellular animals require complex eukaryotic cells, and complex cells need oxygen, which is produced by photosynthesis.
None of these events will occur without the appearance of life – extraordinary events in the chain of all one-time events. All organisms originate from one ancestor. Thus, insofar as it can be judged on the basis of science, life appears only once.
Interestingly, this development requires a very long time. Photosynthesis develops 1.5 billion years after the arrival of the Earth. Eukaryotic cells developed 2.7 billion years ago, complex multicellular animals four billion years later, and human intelligence 4.5 billion years after the formation of the Earth. The fact that these innovations are very valuable, but take a long time, shows that they are very unlikely.
Sequence of unexpected events
One-time innovation and accidental coincidences that are very important can create a chain of obstacles or an evolutionary filter. If that really happens, then our evolution is not just a simple victory in the lottery. That's like winning a lottery in a row. In other words, similar fundamental adaptations on other planets may have been developed too late for intelligence to appear before their star becomes a supernova, and may not appear at all.
Let's imagine that intelligence depends on seven impossible evolutionary innovations: the onset of life, photosynthesis, complex eukaryotic cells, gender differences, complex multicellular animals, bone skeletons, and the development of intelligence itself, each with a 10 percent chance of occurring. Then the possibility of developing intelligent life forms is only one in 10 million.
Complex adaptations may be less likely. A number of adaptations of protein, pigment, and membrane are needed to develop photosynthesis. The emergence of true multicellular cells also requires a large amount of anatomic innovation – nerve, muscle, mouth and the like.
So it is possible that each of the seven major innovations has a one percent chance of developing. If that's the case, then intelligence will develop in only one of the hundreds of trillions of living planets. And because living planets are rare, we may be the only intelligent life form in the entire galaxy, or maybe the entire visible universe.
However, we do exist. This might mean something. If evolution succeeds a hundred trillion times, what is our chance to find ourselves on the planet where this happens?
In fact, the possibility of being in a highly unlikely world like this is one hundred percent. We cannot read this article any other way – we cannot discuss the world without photosynthesis, eukaryotic cells or animals. This is called the anthropic principle: Earth's history should enable the development of intelligent life forms, otherwise we will not be able to reflect on it now.
The development of intelligence seems to depend on a chain of unexpected events. However, given the enormous number of planets, it all seems like an infinite number of monkeys that are spreading infinite typewriters to make Hamlet somewhere. And the impossible result of their creation is us.
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