 advantages and disadvantages of sexual reproduction, first the contents advantages of sexual reproduction, number one genetic variability, number two foundation for evolution and number three elimination of deltidious traits or deltidious mutations. Then the disadvantages of sexual reproduction number one asexual animal cannot survive if there is only sexual reproduction, number two adaptive gene combination will dismantle and number three there is a wastage of energy. So students, first of all if we talk about sexual reproduction, as much as it is natural, as many things are found in it, everything has some positives, some negatives, that is, everything has some benefits, some of them are drawbacks. Usually what we have more benefits, we say this is more useful, this is useful, the drawbacks of which we will say is harmful. For example, we take the eatables that we eat, the food that we eat, where we are taking it in a limit, it is useful, but if we take this food as an over eating, or it is not properly managed, if it is a little spoiled, then what happens? It is harmful. So the same is the thing, in every phenomenon, in nature, all the phenomena have some advantages and some disadvantages. The advantages of sexual reproduction are a little more than that, in case of a problem, where the disadvantages are a little more than that, the overall sexual reproduction is a good thing for animals, it is more prosperous for animals, it is more beneficial for them. Genetic variability, first of all, because of sexual reproduction, there are more variations in animals. Genetic variability also means that there is a new genetic recombination, new gene combinations arise. In sexual reproduction, there are two important events that become the bias of genetic variability. Number one is the meiosis during gamete formation. The meiosis that occurs during gamete formation is that when the recombination of DNA is done, genetic recombination is done. Second one, when fertilization occurs, then one set of chromosome from an animal and another set of chromosome from another animal. Two different set of chromosomes are combined, so there is a new combination of genes. So what will be the benefit of this? The more genetic variability there will be, the more animals can handle the changing environment better. The environment can be more successful, especially the changing environment. As for the environment where the resources are changing, the environmental conditions are changing, the genetic variability there is more beneficial, compared to those species where there is no genetic variability. The second important advantage is that due to sexual reproduction, evolution is becoming a material-available evolution. If we talk about life, it is said that if there are four billion years of life total, then the first two billion years, not the first two Arab years, then the animals have been reproduced asexually. That is why the first two billion years of life has not evolved much. Whereas the two billion years later, the second year after two billion years, the animals will basically go to sexual reproduction, because of which the process of evolution has increased and there is a lot of diversity on the earth. So it means more genetic variability, more variations and more evolutionary processes, more evolutionary processes. Third advantage is that is the elimination of deltidious mutations. You know that mutations are a constant phenomenon. They are different factors in our genome. Sometimes due to chemicals, sometimes due to radiations, sometimes due to internal DNA replication errors. Most of the mutations are dangerous, they are harmful. Very few mutations are beneficial. So the benefit of sexual reproduction is that in sexual reproduction, because there is a genetic recombination, which is reshuffling, the misfit traits that are usually mis-fitted during the reshuffling that is, the deltidious mutations are eliminated and they cannot reach the next generation. Okay, now we have disadvantages. Disadvantages are the first one, that such animals who only do asexually production, those animals who do not have a sexual reproduction method, if they are only sexual reproduction, then they cannot survive. So the same is the case of such animals in which there is a single sex. There are six species of lizards in lizards in which they are only female, they are not male. When you are not male, it means that the population should be extinct. So why are they only surviving due to asexually production? So for this, the animals of asexually production cannot take the option of sexual reproduction, because they will either have the same sex, or they will not have the adaptation, they will not have the structure to reproduce sexually. Second disadvantage is that good combinations. If we have a genetic cloning or genetic engineering, animals have a sheep or a mice who are producing growth hormones. If those animals are producing growth hormones, they are simply using their milk, urine, hormones or protein in medical treatment. If that animal produces sexual reproduction through its offspring, then the maximum chances are that after sexual reproduction, they will not have that quality in their offspring. That means they will not get that protein from their offspring, because during sexual reproduction, when there is genetic recombination, when there is gene reshuffling, the gene that produces protein in milk is eliminated. Same is the case. If there is a stable environment, then the animals that are usually in a stable environment, then their gene combination is very optimum. If there is sexual reproduction there, then the chances are that the good combination of genes is very dismental. And third one is the wastage of energy. Usually, in sexual reproduction, if we take Parthenogenesis for example, if an animal produces 50 eggs or 100 eggs, then 50 and 100 are converted into new animals. What is sexual reproduction? In sexual reproduction, if 50 eggs are produced, if there is 10 fertilization, then all the 40 are useless. They will be wasted. Other than this, the animals that have to do sexual reproduction, they have to come close to each other. They will come close to each other, they will show courtship behavior, they will do mating, and through all these things, there will be a wastage of energy. Sexual reproduction requires more energy, and there is more.