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Anonymous users2024-02-15Who said evolution is measured in 10,000 years? Modern theories of biological evolution believe that evolution is a constant change in the gene pool, which occurs at any time and has no unit of time. However, it usually takes a long time for the external characteristics of living things to change very drastically.
The external characteristics of organisms are determined by genes, and genes cannot change suddenly and drastically, and large genetic mutations in animals will only cause stillbirth and infertility. There are many genetic diseases in human beings, and events such as stillbirths occur in the early embryonic stage, and even if they successfully pass the early childhood, the impact on the gene pool of the entire population is basically negligible, and the population cannot evolve in the direction of mutant species.
According to the modern theory of biological evolution, the cause of the evolution of organisms is the change of gene frequency in the gene pool of the population, and the heritable variation constitutes the raw material of biological evolution. It's just that if the characteristics of the organism have to change significantly, then there are a lot of genetic mutations that need to be accumulated, and this requires a certain process, usually it takes a relatively long time for the external characteristics of the organism to change significantly.
The evolution of animals on the earth is like this, and the evolution of cattle and sheep by human beings has made cattle and sheep evolve in the direction of human beings, but there is only a relatively large migration of external traits, but cattle and sheep have not formed a complete reproductive isolation with wild ancestors, that is, they are still the same species. Human beings have accelerated the natural process of the evolution of cattle and sheep, deliberately selecting a certain breed of cattle and sheep that meets human requirements, and then allowing individuals with similar traits to mate and reproduce, in order to obtain more stable breeds of cattle and sheep.
For example, height, height is affected by multiple genes, but after all, it is a relatively single trait, generally speaking, it is relatively easy to cultivate, modern ponies and other livestock, is the use of continuous crossbreeding, and finally breed purebred to stabilize the dwarf genes, forming a stable genetic line, the cubs they give birth to also have the characteristics of dwarf, artificial intervention has changed the course of their natural evolution, so that the formation of a special population of ponies in horses. But then again, just like the crosses between different dog breeds, the cattle and sheep obtained in this way can still mate and reproduce with other breeds.
The history of human domestication of livestock has thousands to 10,000 years, during which a variety of methods such as crossbreeding and inbreeding have been used, which generally does not occur in the natural environment.
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Anonymous users2024-02-14Because they have a lot to improve, the rate of evolution will be relatively faster than that of humans.
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Anonymous users2024-02-13Because pigs, horses, cattle and sheep are all tamed animals by humans, their evolution will be slow in the natural environment, but these animals have greatly accelerated the process of evolution because of the intervention of human factors.
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Anonymous users2024-02-12Because of human interference, artificial genetic selection, and elimination of pigs, horses, cattle and sheep that are not conducive to human production, it will evolve so fast.
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