What exactly do Neanderthals and us belong to? Anthropologists have been slow to define
1% to 4% of genes in modern people other than Africa are from Neanderthals, are Neanderthals and Homo sapiens a subspecies relationship? Gradual species? Or independent species? Or the sameSpecies? Scientists haven't defined it slowly. I think maybe the words are poor. Let's look at the essence through phenomena and see why scientists are so difficult.
We need to know two things :
1 What is a species
2 Evolution of Homo sapiens and Neanderthals hereinafter referred to as Neders
The direct reason for whether or not individuals can reproduce fertile offspring is not "there is no reproductive isolation", "is it the same species." Species and reproductive isolation are just concepts described by humans.
The inheritance of species depends on the transfer of genes. The direct factor in the evolution of species is also genes. Species diversity is the expression of gene diversity. The sources of gene diversity are genetic mutations, chromosomal mutations, and genetic recombination.
We call all genes contained in the same population as the gene pool of this population. The frequency of genes in the population is called gene frequency.
When species are geographically separated, and the population is separated. Assuming that after 10 billion years, the gene pools of the two populations are not much different, then they are still the same species, and there is no reproductive isolation.
There is not much difference in the gene bank, not simply that the gene has not mutated after 10 billion years. It is divided into two cases :
1 The gene bank is unchanged, what it was and what it is now.
2 Minor changes have been made to the gene bank, such as: black eyes become blue eyes; white skin becomes black skin;
There is another possibility that may not lead to reproductive isolation :
3 Each of them has evolved a new species, and the gene pools are very different, but the evolution direction is close, and there is no absolute reproductive isolation.
If the gene frequency has changed, the species must have evolved, but reproductive isolation may not be formed to form a new species. Reproductive isolation conditions are the accumulation of a large number of gene frequency changes, which promotes very large differences in gene banks. This result willThe formation of new species is a gradual process and requires sufficient time.
The black eyes or blue eyes, white skin, or black skin mentioned above are changes in individual gene frequencies in the gene bank, resulting in changes in traits. Changes in gene frequencies are the result of genetic selection and natural selection of genetic recombination.
This is a little bit round, for example a particle :
An insect population suddenly mutated an individual whose color is close to the color of the tree, and this mutation can also be inherited. Because this color is conducive to protecting itself from being easily discovered, as the population multiplies, the population becomesWith this color. Then the gene that expresses this trait changes the gene frequency from 0 to 100%.
Understanding these things, let's talk about the situation of the Nepalese and Homo sapiens.
Let ’s start with 30 million years ago. At that time, crustal movement and the formation of the Great Rift Valley in East Africa caused the forest on the east side of the Rift Valley to become grasslands. The apes that had originally inhabited the trees had to reduce the number of inhabited trees.Can not live on the ground. Due to the sudden changes in the environment, the apes that have fallen on the ground have gradually evolved from walking on all fours to upright walking in order to adapt to the ground, obtain food, and save energy. After several evolutions such as the southern ancient ape, capable people, and craftsmenLater, 2 million years ago, Homo erectus was born.
The volume of the brain of the upright human in the late period has reached about 1200 ml, and the average height is up to 160 cm, which is very close to modern people. After the accumulation of the ancestors in the front, the upright has already illuminated many skills, such as using fire, making stone tools, and hunting.It doesn't matter what to collect. These skills greatly improve the efficiency of energy harvesting, and also enable the Homo erectus to migrate.
Africa is like a talent market. From generation to generation, people are evolving while sending talents out. There is a steady stream of uprights. There are several routes for erect soldiers to spread out of Africa. Beijingers, Lantians, Yuanmou people in ChinaWait, it's because the Homo erectus migrated.
About 600,000 years ago, a branch of the H. erectus called the Heidelberger. This branch of the Heidelberger also migrated outwards like the predecessors. Some settled in Europe and was called the European Heidelberger. Africa also left a partFurther education, called the African Heidelberg.
250,000 years ago, the early Homo sapiens evolved from Heidelberg in Africa.
230,000 years ago, Neanderthals, descendants of Heidelbergs in Europe, also appeared.
Of course, there were many branches in the same period, but it was a bit inadequate in front of these two. Homo sapiens also wanted to break out of the cage of Africa, but at that time the Ninjas were the rulers of Europe and kept the main point.When the first exit was returned, only a small number of people succeeded. Most of them could only be rebuilt, and they were embarrassed. When Homo sapiens launched the charge for the second time, it was like a firecracker, and it directly dropped all competitors and killed.Eat, eat, assimilate, and in the end, only Homo sapiens are left in the world, which is us.
Modern scientists have found that except for Africa, at least 1 to 4% of the genes of most modern people are from Neanderthals. When Homo sapiens rushed out of Africa, some Homo sapiens remained in Africa, that is,The majority of Africans today do n’t have the Nee gene in their genes. In other words, only Homo sapiens and Nee who broke out of Africa had something unspeakable.
Let ’s go back and look at the relationship between Homo sapiens and Nihons. First of all, they have a common ancestor Heidelberg, but the Heidelbergs who separated the two places have evolved in two different directions under different climates.
I think that the reason why the Nepalese did not have absolute reproductive isolation from Homo sapiens is due in large part to their common ancestors. Heidelbergs are very close to successful people.
The average height of Heidelberg males is 1.72 meters and weight is 62.5 kg. They have a large brain capacity, about 1100 to 1400 milliliters, which is higher than the average value of modern humans at 1,350 milliliters. They already have the ability to make and learn complex thingsAbility, with the language of the basic primitive form.
They can already rely on making foreign objects to resist the environment to screen them, and they have taken a certain initiative in the direction of evolution. This initiative has weakened the changes in the gene bank, as is Homo sapiens. Not so much as they are evolving.They separated the two places from a state of initial understanding of resistance to the environment, and then continued to resist and keep improving under different circumstances. Their main direction of evolution and genetic basis were not much different.
The relationship between the Nepalese and Homo sapiens is the change in the gene bank mentioned above 3. The same ancestor, evolved in different regions, did not produce absolute reproductive isolation. The evolution of nature is intricate and magical, and the definition is onlyIn order to learn and research, it is artificially agreed that only by understanding the essence can we see the answer clearly.
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