CATDOLL : CATDOLL: The reason why grouper changes sex

1. The reason for the sex change of grouper

According to a recent British survey report, male animals have a serious tendency to become feminized due to the influence of "environmental hormones". 60% of groupers living in rivers discharged from factories have undergone sex change, and many male groupers can even ovulate, and hermaphroditic fish have appeared.

The so-called "environmental hormones" refer to a class of harmful substances released into the environment due to human activities. They play a role similar to estrogen in the bodies of animals and humans, causing endocrine disorders and reproductive dysfunction in these animals.

"Dioxin" is a typical type of environmental hormone. In fact, dioxin is a general term for a class of chlorine-containing compounds, of which there are about 200 kinds. Among them, "2,3,7,8-tetrachlorodibenzo-isodioxin" (TCDD) is the most toxic. Its median lethal dose is 1 microgram/kilogram (1 microgram...

2. A little girl asked me why groupers change sex. How can I answer her in a simple and understandable way?

You just say: Groupers will decide whether to be a mother or a father after they reach adulthood, depending on their mood.

3. Which kind of fish will change gender when it reaches a certain age?

Blue Grouper and Eel

IV. Sex Reversal in Animals

Under certain conditions, the phenomenon of male and female individuals of animals transforming into each other is called sex reversal. As early as more than 2,000 years ago, there was a record of hens crowing at dawn in the "Book of Han". Sex reversal in fish is relatively common. For example, the gonads of yellow eels are ovaries from embryo to sexual maturity, which can only produce eggs. After laying eggs, the ovaries slowly transform into testes, which only produce sperm. Therefore, every yellow eel goes through two stages of male and female in its life. Mature female swordtail fish will unexpectedly become male fish, and old female eels sometimes turn into male fish. A large number of studies have shown that exogenous hormones can play a role in sex reversal. Using steroid hormones to treat young and juvenile fish during the critical period of gonadal sexual differentiation can obtain single-sex or primary single-sex populations. From the perspective of animal species, adult fish and frogs can change their sex under the influence of hormones or other factors. Chickens also have the phenomenon of "hens crowing at dawn", and hormones can be used to change the sex of undifferentiated chicken embryos. Adult mammals, including humans, cannot change sex, but if sex hormones are given to embryos before they have sexually differentiated, the embryos can become hermaphrodites. The reason for this is partly due to evolutionary differences, but more importantly, fish and frogs, as well as female chickens and chicken embryos, all have the material conditions for sex change - there are undifferentiated parts of the reproductive glands, so they can change sex when conditions are right, while roosters and adult mammals do not have this structure. Whether it is possible for mammal embryos to change before the sexes have differentiated needs further research.

5. Do groupers have phototaxis?

Phototropism is a habit of organisms moving closer to or away from light. In the plant kingdom, this habit is often found in chloroplasts of wandering plants, such as various algae, wandering green algae, flagellates, and dinoflagellates. In the animal kingdom, the moth flying into the fire is a typical example. Phototropism is a type of biological stress response and is the result of long-term natural selection.

Moth midges are phototactic.

6. Why do fish have hermaphroditism?

Haha, it depends on what kind of fish it is. Most fish are not hermaphroditic. Herring, cod, yellow porgy, flounder and other fish all have hermaphroditism. In the Perciformes genus, there are several fish that are permanent hermaphrodites. The only fish that can self-fertilize is sea bass. It is said that there is a small hermaphroditic grouper in the Percidae family in the Gulf of Mexico, which also self-fertilizes. Among vertebrates, this rare phenomenon is only found in fish. In addition to the self-fertilizing sea bass, the mating method of hermaphroditic fish is like that of earthworms, and fertilization requires two individuals to complete. Yellow eel is also a fish, and the gender of yellow eel often makes people question it. The body of a small yellow eel is full of eggs, while the body of a large yellow eel is full of milt. The gonads of almost all yellow eels are ovaries from the embryonic stage to maturity, that is, when the yellow eel is young, it is female. After spawning, the ovary changes and slowly becomes a testis. In other words, the eel changes from female to male, and remains male until death, and its gender no longer changes. In biology, this special physiological phenomenon of the eel changing from female to male is called sex reversal. The sex reversal of the eel is not a mutation that occurs in a certain individual, but a developmental law of the entire species. The young eels hatched from eggs will lay eggs in the first year, and then turn into male eels in the second year, mating and laying eggs with the next generation of female eels. In this way, there is a batch of sex-changed male eels every year, and a batch of newly grown female eels every year, so the marriages of the eels are all "old man and young wife." Agree 9| Comment