CATDOLL : CATDOLL: Is artificial selective breeding natural selection?

1. Is artificial selection breeding natural selection?

Artificial selection breeding is not natural selection. Natural selection is the result of the interaction between organisms and the environment. Under natural living conditions, some vulnerable groups will be eliminated, thereby evolving better and more environmentally adaptable characteristics, ensuring the inheritance of excellent genes of the species.

Artificial selective breeding is the process of selecting the characteristics that one wishes to see in a species and breeding them in order to achieve more efficient economic value.

2. What is the index selection method in the selection of breeding beef cattle?

The index selection method is to select based on the comprehensive selection index. This index uses the principle of quantitative genetics to give different appropriate weights to the phenotypic values ​​of several traits to be selected according to their heritability, economic importance, and phenotypic correlation and genetic correlation between traits, and formulate a value that allows individuals to be compared with each other, and then select based on this value.

For the sake of comparison, the selection index value of individuals with all traits at the average value of the herd is set at 100, and the other individuals are compared with 100. Those with more than 100 are excellent and are retained, while those with less than 100 need to be eliminated. The effectiveness of the index selection method mainly depends on whether the weighted value is formulated reasonably.

The weighted value of each trait is mainly determined by the relative economic value of the trait, the heritability of each trait, and the genetic correlation between the traits. In addition, there are other advanced methods for selecting beef cattle breeders, such as the best linear uncoded prediction method (BLUP method) and the new animal model method.

3. How to choose the breeding method for Bougainvillea?

Hello, I’m Qinggege. Bougainvillea is a very beautiful and elegant plant. Let me answer this question!

Bougainvillea is often planted on porches, walls or courtyards. During the flowering season, its branches and vines intertwine, like a peacock spreading its tail. It is particularly beautiful and has become a favorite flower for many flower lovers. However, it has poor cold resistance. If no protective measures are taken, it will shed its leaves at 5 degrees Celsius and will be frozen to death at minus 10 degrees. Therefore, many southern friends plant bougainvillea. Aside from the disadvantage of cold resistance, bougainvillea has a very good ability to bloom.

If you want to cultivate bougainvillea, you can use the cutting method. It is relatively simple, but you need to cut a stronger branch from a thicker plant. Don't cut it too long. First find some loose soil and insert it into it. It is better to wait until the roots of bougainvillea grow out and survive before transplanting. Prepare the flower pots in advance. You can put some leaf mold and some garden soil from the park in it. It is best to find some sand and mix them together. These soils are all relatively breathable.

Bougainvillea likes a warm and humid environment and can withstand high temperatures. High temperatures above 35 degrees Celsius in summer have little effect on Bougainvillea. However, the roots of potted Bougainvillea are not very developed. When the temperature is above 35 degrees Celsius, it is better to shade the Bougainvillea appropriately at noon.

After each time the bougainvillea finishes blooming, the branches of the bougainvillea must be pruned. Part of the longer and thicker branches must be cut off. This way, the branches and leaves of the bougainvillea are reduced, and the excess nutrients can be transferred to the flowers, making the flowers more beautiful.

For grafting, you need to choose fat branches as scions, preferably branches about one year old. Such branches can germinate the fastest and have a higher survival rate. When grafting, the rootstock and scion should be tightly attached together, and then the grafting site should be covered with film. The grafted branches will sprout new buds in about 8-10 days.

The selective breeding method is based on natural variation and is divided into seed selection and bud mutation selection. Seed selection is a method of selecting excellent variation types from the seed population formed after sowing the seeds of Bougainvillea produced by natural pollination, and then cultivating new varieties. Because it is difficult to collect Bougainvillea seeds, especially many Bougainvillea varieties do not bear fruit, it is almost impossible to collect a large number of them, so the seed selection method is not commonly used on Bougainvillea, and the bud mutation selection method is more commonly used.

Bud mutation is a type of somatic mutation that occurs in the meristem cells of the plant buds. The branches that grow from the mutated buds and the individuals formed thereby will show different characteristics from the original types. Bud mutation is relatively common in Bougainvillea. For example, some varieties have hairy coats, disappearance of branch thorns, changes in bract color and number, complete and incomplete development of flower tubes, and various color spots on the leaves.

The above is the breeding method of bougainvillea. I hope it can be helpful to everyone! I wish everyone can grow beautiful bougainvillea!

4. Selection is the main work content of crop genetic breeding. How to improve the efficiency of selection?

1. Develop practical breeding technology routes and plans to reduce blindness.

2. Conduct a comprehensive evaluation of the genetic traits of the basic breeding materials to determine the heritability and combining ability of each trait.

3. Take advantage of the suitable light and temperature environment in other places to carry out additional generations and expand propagation to speed up the progress of generations.

4. Use auxiliary means such as molecular markers to improve selection efficiency.

5. Use scientific and advanced selection methods to determine the appropriate planting population, reduce the field population and reduce the workload of selection while ensuring the probability of the target plants appearing.

5. What are the commonly used methods of microbial breeding?

Mutation breeding.

Common methods of microbial breeding include:

Mutagenesis breeding, gene recombination breeding, genetic engineering breeding, metabolic regulation breeding, etc.

6. How do fish adapt to temperature changes?

1. Physiological regulation.

The sensitive organs of fish are the microvessels in the skin and gill blood vessels. The nerve center that controls the body temperature regulation is in the hypothalamus. However, fish cannot lower or increase the temperature by adding or removing clothes or turning on the air conditioner like humans do, so as to protect themselves from the adverse effects of the external environment temperature. The way fish regulate is through body fluid regulation. Body fluids include blood, tissue fluid, lymph fluid, water, etc. in the body. Through the physiological coordination of body fluids, the body temperature is kept as close as possible to the surrounding water temperature.

2. Dynamic adjustment.

Because the temperature of water is different from that of the atmosphere, and because the density of water is greater than that of air, the heat transfer and heat release of water are slower than those of the atmosphere. In addition, water has three layers: upper, middle, and lower, and the temperatures of these three water layers are also different. The deeper the water, the greater the difference. According to measurements by scientific and technological workers in a certain reservoir, when the temperature of the upper layer (surface) of water is 21.2℃, the water temperature at a depth of 1 meter is 18.3℃, and the water temperature at a depth of 2 meters is 17℃. In winter, when the surface temperature of water is 4.3℃, the temperature at a depth of 1 meter is 4.5℃, and the temperature at a depth of 2 meters is 4.9℃. When the temperature of a certain layer of water is not suitable for a certain fish to live in, it will look for a water layer suitable for its own life.

7. What is the commonly used method of polyploidy breeding?

Haploid breeding: 1. (Heterozygous) Anthers are cultured in vitro to obtain haploid seedlings. 2. Then the seedlings are treated with colchicine or low temperature is used to induce chromosome doubling to obtain diploid plants. Purpose: To obtain homozygous plants

Polyploid breeding: Polyploid plants are obtained by treating germinated seeds or seedlings with colchicine or low temperature induction.

Purpose: To obtain new biological species

8. How to adopt appropriate selection methods based on the plant’s reproduction method and breeding tasks?

Hello, different plant propagation methods and breeding tasks require different selection methods. Here are some common selection methods:

1. Sexual reproduction: For plants that reproduce sexually, genetic breeding methods can be used to select individuals with good traits for mating in order to produce better offspring. Common selection methods include parent selection, single plant selection, family selection, etc.

2. Asexual reproduction: For plants that reproduce asexually, asexual reproduction methods can be used for breeding. Common selection methods include selecting excellent mother plants for cuttings or grafting in order to obtain more excellent offspring.

3. Hybrid breeding: For plants that require hybrid breeding, hybrid breeding methods can be used for selection. Common selection methods include parent selection, hybrid combination selection, and offspring selection.

4. Gene editing: For plants that need gene editing, gene editing methods can be used for selection. Common selection methods include CRISPR/Cas9 technology.

5. Genetic improvement: For plants that need to be genetically improved, genetic improvement methods can be used for selection. Common selection methods include marker-assisted selection, genomic selection, etc.

In short, choosing an appropriate selection method requires evaluation and analysis based on the plant's propagation method and breeding tasks, and selection based on actual conditions.

9. What is the main method of seawater desalination at present?

Distillation

Although distillation is an ancient method, it still dominates today due to the continuous improvement and development of technology. The essence of the distillation and desalination process is the formation of water vapor. Its principle is just like seawater evaporates to form clouds when heated, and clouds form rain when cooled under certain conditions, and rain does not have a salty taste. According to equipment distillation, steam compression distillation, multi-stage flash distillation, etc.

Reverse Osmosis

It is also commonly known as ultrafiltration, which is a membrane separation desalination method that was only adopted in 1953. This method uses a semipermeable membrane that only allows solvents to pass through but not solutes to pass through to separate seawater from freshwater. Under normal circumstances, freshwater diffuses through the semipermeable membrane to the seawater side, so that the liquid level on the seawater side gradually rises until it stops at a certain height. This process is called osmosis. At this time, the static pressure of the water column on the seawater side is called osmotic pressure. If an external pressure greater than the osmotic pressure of seawater is applied to the seawater side, the pure water in the seawater will reverse osmosis into freshwater. The biggest advantage of reverse osmosis is energy saving. Its energy consumption is only 1/2 of that of electrodialysis and 1/40 of that of distillation. Reverse osmosis seawater desalination technology has developed rapidly, and the project cost and operating cost have continued to decrease. The main development trends are to reduce the operating pressure of reverse osmosis membranes, improve the recovery rate of reverse osmosis systems, cheap and efficient pretreatment technology, and enhance the system's anti-pollution ability.

Solar Energy Law

In the early days, humans used solar energy to desalinate seawater, mainly using solar energy for distillation, so early solar desalination devices were generally called solar stills. An example of a passive solar distillation system is the disc solar still, which has been used for nearly 150 years. Due to its simple structure and convenient material acquisition, it is still widely used. At present, research on disc solar stills mainly focuses on the selection of materials, the improvement of various thermal properties, and its use in conjunction with various solar collectors. Compared with traditional power sources and heat sources, solar energy has the advantages of safety and environmental protection. Combining the two systems of solar energy collection and desalination process is a sustainable desalination technology. Solar desalination technology has gradually attracted people's attention due to its advantages of not consuming conventional energy, no pollution, and high purity of fresh water.

10. Which fish is the best to grill? Which five common fish are the best choices?

Generally, saltwater fish are more suitable for grilling, such as small yellow croaker, oil button, and salmon. Of course, the most suitable fish for grilling is cod (called Pollack by the Koreans)!