The fundamental difference between man and animals lies in consciousness. Man has consciousness, but animals have no consciousness. Therefore, man has subjective initiative, that is, he can analyze things, observe things carefully, and create and use various tools. We humans are also animals, but we can be called advanced animals by virtue of this difference. But can’t higher animals and lower animals cross? In zoology, hybridization probably means that two different kinds of individuals breed creatures. Obviously, human and other animals are certainly different kinds of individuals. Then the question comes, why can’t human and animals crossbreed?
Ivanov’s hybridization experiment
1. Ivanov’s first experiment
During the period of the former Soviet Union, Elia Ivanov, a reproductive biologist, conducted experiments on the reproduction of orangutans. The process of the experiment was very tortuous, but there was a rumor that “orangutan man” was true or false. But did gorilla man really exist? Why is there such a professional term for orangutan?
Ivanov graduated from Kharkov University. He had considerable attainments in artificial insemination of animals. This technology improved the development of energy storage and animal husbandry in Russian agriculture at that time, so it was strongly supported by Russia. Ivanov did not stop, and then put forward a bold guess and attempt, he wanted to try the way of artificial insemination, human and other primates hybrid.
The picture shows Ivanov
However, due to the very difficult conditions in the Soviet Union after the October Revolution, the state was unable to provide Ivanov with sufficient research conditions, but Ivanov did not give up and still looked for channels to meet his own research. Finally, Ivanov sought support from the Pasteur Research Institute in France, but it was unsatisfactory that he could only provide experimental bases, and the funds needed to be worked out by himself There is an experimental base that is very satisfied with Ivanov. Ivanov knew that his own funds were not enough for this experiment, so he went back to seek funding from the top of the Soviet Union for his research. Fortunately, he got strong support from the top of the Soviet Union, and the top officials thought that how to succeed in the research could solve the problems of “materialism” and “religious decisiveness”. As a result, Ivanov successfully received financial assistance and an experimental base.
So in November 1926, Ivanov, his son and a student came to Pasteur’s research base in West Africa. But the first research experiment failed. According to the information, the first experiment used female chimpanzee and human sperm. It is said that the sperm was provided by the father and son. Xiaobian thinks it is possible because the conditions and equipment of the experimental base are not generally poor. Just as Ivanov was preparing to carry out the second experiment, due to the exhaustion of funds, the plan for the second experiment had to stop, and then they returned to China.
2. Ivanov’s second experiment
The Soviet Academy thought that Ivanov was very dissatisfied after the deadlock between Africa and the local people, and cancelled the financial assistance. After several twists and turns, Ivanov got the support of several famous domestic scientists and was able to continue his second experiment.
The plan is to hybridize male chimpanzees with human females. According to the news, five volunteer females wrote letters to ask to participate in Ivanov’s hybridizing experiment. They saw that all this went well, but it didn’t last long. The chimpanzees to be experimented didn’t adapt to the climate of the gaojiasuo region, and the experiment began to go wrong from 1928 to 1929 Only one gorilla met the experimental requirements, but died of cerebral hemorrhage.
In 1930, the gorilla from Africa arrived immediately, but the emergency ended his experiment: Ivanov and the scientists who were also doing primate reproduction research lost their jobs due to political turmoil, Ivanov was also politically accused and finally exiled to Almaty. Although Ivanov was released early in 1932, he died of illness.
It’s a pity that the experiment stopped. But there are rumors that later generations have done similar experiments and have also given birth to chimpanzees. However, rumors are rumors after all, and it is impossible to confirm whether humans and animals can really hybridize.
Ivanov is said to have done similar experiments in China
Why is there reproductive isolation?
Before we can understand reproductive isolation, we need to define: what is species?
The evolution of nature is magical and complex, and those definitions are artificially agreed by us in order to understand the convenience of nature. The definition of species used in our textbook: species is the basic unit of biological classification. Species are developed from common ancestors and are the basis of continuous evolution. Different species have different ecological characteristics. This definition emphasizes the concept of “reproductive isolation”. In this system, when a species evolves to “reproductive isolation”, we say that a new species is born.
So from another perspective, it is not because of reproductive isolation that there are all kinds of different species, but because there are all kinds of different species, there is reproductive isolation.
There are two necessary conditions for the birth of a new species: firstly, it must be a new species; secondly, it must be able to survive; finally, it can reproduce new offspring on its own.
Therefore, when crossbreeding between organisms, the following situations will generally occur:
There are too many species to fertilize
Here is a simple example. The sperm of a fly is 6cm long, while the egg of a human is less than 2mm long. Do you think the sperm of a fly can fertilize the egg of a human?
In fact, sperm and egg cells are like a key and a lock. The egg cell has a ligand receptor on its surface. Only the corresponding sperm can open the “lock” and produce a fertilized egg, just like kangaroo and bullfrog. Even if they mate, they cannot be fertilized.
The picture shows the sperm of a fly
The chromosome structure is too different
Suppose that the bullfrog’s sperm successfully broke through the line of defense of kangaroo eggs and was ready to give birth to a new life. However, due to the far difference between the two chromosome structures and the different gene sequences responsible for development and metabolism, the bullfrog’s sperm expressed their own strange proteins, and the egg cells were likely to be disorganized, metabolized and unable to survive.
Unable to breed
It’s like a liger. Liger is the offspring of a female tiger and a male lion. They are fertilized successfully and their genes can be expressed correctly. However, because of the odd number of chromosomes, liger can not produce offspring and can not be regarded as an independent species. In the same way, there are mules, the offspring of donkey and horse.
The picture shows the lion and tiger
In fact, we can assume that if from the moment of birth of life on earth, all species can freely mate and produce offspring, then the world will be all kinds of “monsters”. From a certain point of view, it can be understood that there is only one species. It is precisely because of a variety of different environments, resulting in a variety of evolutionary directions between different species, so that the fitness of different species has been improved. In other words, it is the reproductive isolation caused by different species that makes the evolution of species more directional and stronger.
Can humans and chimpanzees have offspring?
Back to the point, if Ivanov’s experiment is not terminated, can humans and orangutans have offspring?
After gene sequencing, scientists have found that the genetic similarity between human and chimpanzee is as high as 96%, which is enough to prove that human and chimpanzee are close relatives. But that 4% is determined by the difference in intelligence between humans and chimpanzees, known as the smart gene.
But even so, both humans and chimpanzees belong to the hominid category, just like tigers and lions belong to the feline family. So many people speculate that they can produce infertile offspring. But is this really the case? Many mainstream scientists believe that humans and chimpanzees can not produce offspring, but this involves ethical issues. We would rather acquiesce that humans and chimpanzees can not produce offspring than do such ethical and immoral experiments. This is also an important reason for the failure of Ivanov’s experiment.
Do humans and all living things have reproductive isolation?
As we all know, reproductive isolation is generally divided into three types: gene mutation, chromosome variation and gene recombination.
Gene mutation is the change of gene structure caused by the addition, deletion or replacement of base pairs in DNA molecules. Chromosomal variation naturally refers to the change of the number of chromosomes, so gene recombination is a little more complicated. Gene recombination refers to the recombination of genes controlling different traits in the process of sexual reproduction. Gene recombination did not produce new genes, so it could not produce new traits, but could produce new genotypes.
There are three stages in reproductive isolation
First, there are some gene changes among species, and then those genes need to adapt to the new natural environment, and then be preserved by the natural environment. It’s a very important part of geographic isolation. If you don’t have this last step, the first two steps will be futile. After all, you can’t do things without end. It’s because geographic isolation separates different organisms. After thousands of years of change, different groups of organisms have no gene exchange, and they are moving forward on their own evolutionary path Gradually there was reproductive isolation.
In the process of evolution, human beings are a highly intelligent group. They have been on the way of their own evolution and have no communication with other creatures. So gradually, with the passage of time, we also have reproductive isolation from other species. Although it is mentioned in the theory of evolution that the ancestors of human beings are apes, after thousands of years of evolution, all kinds of primates and human beings have long been two worlds. Due to various reasons: time, place, events and so on, we have become human beings, full of wisdom.
Of course, if you want to ask me why there is no reproductive isolation between Europeans and Asians, I can answer you like this: there is no reproductive isolation among people all over the world, because the genes of my foreign friends and I are mostly the same. With the development of science and technology, airplanes and ships have brought people all over the world closer to each other, so it is almost impossible to say that the reproductive isolation between human beings is real Now.