What kind of ability is "self-replication"?

Everyone knows that in order to survive, organisms will use genetic mutations to adapt to the environment, and the "marbled crayfish" is an organism with the "self-replication" ability produced by genetic mutation. As early as 2018, there were reports that the descendants of marbled crayfish had invaded freshwater ecosystems throughout Europe in the past 25 years, which shows how strong its "self-replication" ability is.

Many netizens are wondering what the "self-replication" ability is. Is it like the unlimited clones of the shadow clone? Today, let's talk about what "self-replication" is. What are the dangers of marbled crayfish? What are the weaknesses of asexual reproduction?

01. What is “self-replication”?

In fact, the so-called "self-replication" is actually a very common asexual reproduction mode in nature.

We know that humans need a man and a woman, and animals need a male and a female to produce offspring. But in fact, this way of reproduction, that is, sexual reproduction mode, is a very late phenomenon.

In the early days of the Earth, there was no concept of gender, and most organisms reproduced asexually. Moreover, this mode is still one of the mainstream reproductive modes today (don’t be confused by animals and plants, compared to microorganisms, animals and plants don’t even have fur).

For example, the fungi that everyone is familiar with reproduce asexually.

Of course, you may say that bacteria are too microscopic, so let’s talk about something macroscopic.

A familiar food: potatoes. We love all kinds of potato foods, mashed potatoes, French fries, potato chips, etc., and of course, shredded potato stir-fry.

But have you ever seen potato seeds? I guess few people have. Most people know that potato propagation is to cut the potato and then bury it.

This is typical asexual reproduction.

02. What are the dangers of marbled crayfish?

A concept that everyone is familiar with is biological invasion. The so-called biological invasion refers to the process in which organisms invade another new environment from their original habitat through natural or artificial means, causing economic losses or ecological disasters to the biodiversity, agricultural, forestry, animal husbandry and fishery production, and human health in the invaded area. Therefore, the biggest harm of marbled crayfish is the impact of its rapid reproduction on the ecology. An important reason for this phenomenon is the lack of natural enemies.

For example, the famous water hyacinth, in order to control Dianchi Lake, the country introduced a large number of water hyacinths from Japan. As a result, this plant had no natural enemies in Dianchi Lake and reproduced wildly, and finally even deteriorated the water quality of Dianchi Lake. As a result, the country had to spend a lot of money to control Dianchi Lake.

The same goes for crayfish.

This creature is also very adaptable to the environment. It can adapt to a wide range of temperatures, salinity, and pH. It can jump around in warm waters above 30°C and can live comfortably in water currents under the ice. It can make its home in lakes, rice fields, or swamps, and eats both vegetarian and meaty food. Algae, rotten leaves, snails, fish eggs, small insects, and small fish are all within its hunting range. If it is really hungry, it will even eat wood, as it can digest cellulose.

This is the harm of crayfish. They lack natural enemies and reproduce wildly, which leads to disaster.

03. What are the weaknesses of asexual reproduction?

The biggest risk of asexual reproduction is the lack of resistance. Sexual reproduction will have a lot of recombination, so there is enough ability to fight diseases, which is also the source of the world's diversity.

However, asexual reproduction is essentially the cloning that everyone is familiar with. One of the biggest problems with cloning is the lack of recombination mutation, so if one virus is harmful, the others will suffer as well.

This is not impossible. The potato, which is familiar to everyone, once suffered a particularly great disaster. Potatoes were once the only crop that the Irish relied on for survival. However, between 1845 and 1850, a pathogen infected potatoes. Since potatoes reproduce asexually, the virus spread everywhere, causing a serious famine in Ireland at the time. In just five years, a quarter of the Irish population starved to death. It is still a famous famine event in human history.

Therefore, the advantage of asexual reproduction is fast reproduction, and the disadvantage is its single nature.

The result of lack of diversity is that once encountering natural enemies, it is really a threat of extinction. Clones also have a similar lack of diversity problem.

Finally, let me explain that there are some conceptual disputes about parthenogenesis and asexual reproduction. For example, some people believe that asexual reproduction includes parthenogenesis, that is, the reproductive process that does not go through the union of male and female gametes is called asexual reproduction; others believe that parthenogenesis is different from the division and proliferation of bacteria.

The former view is adopted here. After all, the entire reproduction process does not involve the fusion of male and female gametes, which is itself an asexual manifestation.