动物实验 z-bo 2020-09-28 379

　　According to foreign media reports, a recent study conducted by Adam Hart, a scientist at the University of Gloucestershire in the United Kingdom, found that humans have unintentionally affected the evolution of other species. A growing body of evidence shows that human activities such as commercial fishing, hunting, and the use of pesticides and antibiotics have brought about many great changes in species evolution. When you sit at the table and prepare to enjoy delicious grilled chicken, you may not even think of the evolution of this species. However, if you look closely, you will find something strange. Their thick and crisp carrots, tender and delicious chicken, and red and shiny tomatoes are clearly different from their natural ancestors. These artificially raised livestock and planted crops are usually artificially selected under the influence of humans, such as taste and size, and the gene frequency varies between the descendants and ancestors of animals and plants. This genetic change is evolution, and the above-mentioned evolution is produced by the process of "artificial selection".

　　In fact, natural selection is basically the same process. The difference between the two is that artificial selection is deliberate selection by humans to feed and nurture individuals, but the pressure of natural selection comes from the strong food of the weak and the most suitable survival. It means to come. For example, women never want to mate with inferior men. Individuals reproduce high-quality offspring, while other inferior individuals rarely have the opportunity to reproduce offspring. If this trait that allows parents to increase fertility follows certain genetic guidelines, their offspring will inherit the trait and change the genetic frequency of this group.

　　Of course, not all manual pressure selection is intentional. Scientists’ latest research has found that many human activities have unintentionally had a major impact on species evolution. This "unnatural selection" also promotes species evolution. It can be said that the most famous and important example of "unconscious evolution" caused by human activities is antibiotic resistance. Antibiotics have brought great evolutionary pressure on bacteria. Bacteria that can withstand the pressure of antibiotics have great advantages. The same is true for pesticide resistance.

　　Famous examples of unnatural selection and evolution include commercial fishing. Generally, larger fish are easy to catch on land, but smaller fish can survive. However, this impact is not just a statistical change. Eric Parcovacos, a scientist at the University of California, Santa Cruz, explained: “Eliminate large fish that directly affect the individual size of a particular fish group. Other fish groups can feel it. This is because the remaining small fish donated more genes. In other words, the "small" genes were passed and the "big" genes were selectively excluded for commercial fishing.

　　Commercial fisheries not only affect the development of individual fish schools, but also affect the sexual maturity of individual fish schools, leading to the premature maturity of individual fish schools. Individuals with slow maturation genes landed before reproducing offspring, so this part of slow maturation genes in fish schools was also excluded. This selective pressure and evolution caused by commercial fishing have more serious impacts on the ecosystem. For example, Atlantic cod used to be several meters long, but now it is only about one meter long. Parkovac explained: “In the ecosystem, certain creatures may be the most important predators, but now they are prey to other creatures.”

　　In addition, hunting has a great influence on the evolution of species. .. Rocky Mountain bighorn sheep are distributed in Alberta and other places and have always been the target of hunters. Hunters like to hunt the largest and most impressive male bighorn sheep. These big men have strong horns and are more likely to win when fighting with other men, so they are more likely to defeat small horned sheep and increase their chances of mating with women. The research team of Professor David Coltman, a scientist at the University of Alberta in Canada, has been studying Rocky Mountain bighorn sheep for 40 years. They found that Rocky Mountain bighorn sheep grow quickly when they are young, but successful rams must live long enough to gain social benefits. If it succeeds, there can be many offspring. Hunters exerted strong evolutionary pressure on these big horns. Their huge advantages quickly turn into disadvantages, because they are ideal prey for hunters. This pressure gave the bighorn sheep an opportunity. As the big guy was hunted and the little guy grew up, their genes were inherited. Just like fishing, hunting also leads to evolutionary changes. As a result, the Rocky Mountain bighorn sheep have become smaller and smaller, shrinking by 25%.

　　When fishing and hunting, we behave differently from natural enemies. We are ruthless "super predators", choosing only the biggest and best targets. Likewise, in a constantly changing environment, our approach is great. The urbanization process is still continuing. If certain species want to survive, they must endure the environment we create. On a global scale, our activities have caused climate change and put greater pressure on species evolution. Everything we do seems to have a corresponding evolutionary result.

　　Men's competition can promote the formation of new species

　　According to foreign media reports, can sexual selection lead to the formation of new species? This question has always been controversial among evolutionary biologists. Most previous studies focused on natural selection. Some studies considered sexual selection, but mainly focused on the relationship between mating women’s selection and evolution. Yes, a recent study by a biologist at Michigan State University found that fierce competition between men plays an important role in the formation of new species.

　　Michigan State University biologists track and study the back. The results of the study indicate that fierce competition among men plays an important role in the formation of new species. Moreover, this competition can even eliminate the boundaries between different species. Janet Bowman, a biologist at Michigan State University and one of the leaders of the research project, said: "This is the first time that fierce competition between humans has divided the population. This is why our paper has received special attention. . That’s why integration plays a very important role.”

　　Researchers say that this kind of competition between people is a bit similar to a basketball game. A certain freshwater spinyfish, its color is mainly blue, its movement is very flexible and fast like a guard. Another type of spinyback is a deep-sea fish, which is completely black and has a large body, just like the front center. Of course, this type of game is not played on the basketball court, but in a hidden place. The female spines are only willing to mate with men who have nests. The male deep sea spinyback dog stands firmly in the penalty area to prevent the enemy from shooting and protect the nest. The soft male freshwater barfish flies over the opponent's defense line and directly destroys it while protecting the opponent's nest. Both methods are effective. Therefore, men's ottomans can be "beautiful" in return.

　　Janet Boffman’s research team also includes biologists such as Jason Kigi and Liliana Littleri. Buffman said: "We have found that sexual selection can lead to the formation of new species in unexpected ways. This tells us which men's back sticks will eventually enter the mating zone when male-dominated competition competes with each other." The findings indicate that male competition is the main driving force for the formation of new species. This factor is five times more important than other factors, which are traditional factors. This is the basis of natural selection theory.

　　Thousands of hours of observation time were spent, such as observing behavior, such as protecting the nest and mating. During the observation process, the food source, environment and predatory behavior of stick did not change. Natural selection considers all these factors. Biologists believe that the abnormal results were found because the spinyfish has long been regarded as a faithful performer of natural selection.

　　Of course, environmental changes and species loss are not limited to slime fish. In Africa, due to the influence of agriculture, other fish such as cycloidal needles are gradually disappearing. In other regions, such as the Great Lakes and Switzerland, pollution has also changed the types of white fish. Due to strict pollution control over the past 15 years, white fish in Switzerland have recovered, but the fate of white fish in the Great Lakes is still unknown.

　　Humans will evolve into a new species in 2050

　　According to the acquisition report, can technology "evolve" into a new species? Experts believe that the so-called "human Optimus Prime" superman can talk to machines and achieve "digital immortality."

　　If you are under 40, you have a good chance of achieving "digital immortality". This is the concept of uploading and storing all thoughts and experiences online for future generations to use. This idea originated from the futuristic Ian Pearson. Pearson believes that technology is not only expected to achieve human-machine integration, but will also create a new species "homoptimus." This new species has high sensory organs, is a mixture of humans and computers, and may be realized in 2050.

　　What are the consequences of species evolution and genetic mutation?

　　Biology tells us that DNA has copied genetic information from generation to generation. The fidelity of DNA replication is the main factor in maintaining the relative stability of species. However, this fidelity is relative. Under certain conditions, DNA molecules may be destroyed or mutated. There are two types of this result, one causing replication or transcription failure, and the other causing genetic mutations after replication, making permanent changes to the DNA sequence.

　　Generally, we tend to mistake mutations for life threatening. Indeed, certain genetic mutations can lead to genetic and neoplastic diseases. However, DNA mutation has both disadvantages and advantages. From the long-term history of biological evolution, the fundamental cause of species evolution is the continuous development of genetic mutations. Without such genetic mutations, the current biological world cannot exist.

　　Only mutations with a genotype change form DNA polymorphisms. This phenomenon is very common, and some mutations have no obvious morphological changes. In the medical field, you can design a variety of techniques to identify individual differences and differences between species and strains, such as personal identification in forensic medicine, paternity testing, organ transplant matching, and sensitivity analysis of individuals to specific diseases. DNA polymorphism analysis technology. However, certain gene mutations that are essential in life can cause cell and individual death. People often use these properties to eliminate harmful pathogens.

　　People usually think that mutations are harmful. It mainly refers to specific mutations that cause a variety of diseases, such as genetic diseases, tumors and diseases with genetic susceptibility. Some people already know where the genetic defect is. For example, hemophilia is a mutation in the clotting factor gene and a mutation in the hemoglobin gene in hemoglobinemia. Diseases with genetic susceptibility, such as high blood pressure, diabetes and tumors, are of course related to the living environment, but there is also evidence that certain genes have mutations. However, many genes are involved, but this is the result of many genes and living environment factors.

　　Geneticists believe that there can be no genetics without mutations. Mutations are also considered to be the "driving force" of species evolution. In the process of natural selection, insufficient mutations are eliminated and mutations beneficial to the species are accumulated.

　　Then what is the relationship between genetic mutation and genetic modification and hybridization? Gene mutation, hybridization and genetic modification are all different methods of biological mutation. Gene mutation and hybridization are natural selection, but genetic modification is artificial. Gene mutation is the addition, deletion or modification of gene bases that produce new genes. The introduced genes belong to genetic recombination, and no new genes will be produced. Hybridization is the result of humans learning from nature through various combinations. Environmental variables increase the possibility that mutations will change the genes of offspring.