What is Parthenogenesis?

Parthenogenesis is also called parthenogenesis, that is, eggs can develop into normal new individuals without fertilization. Parthenogenesis is a reproductive phenomenon common to some primitive animal species.

In the animal kingdom, egg cells produced by some types of female individuals can develop into new individuals without undergoing sperm action. This phenomenon is called parthenogenesis. Such as aphids in insects, spitting birds in birds.

Parthenogenesis can also be promoted artificially. In lower animals, treatment with hypotonic or hypertonic solution, high temperature or low temperature, electrical stimulation or chemical stimulation can make parthenogenesis of sea urchin eggs. Chinese biologist Zhu Xi once used blood cells to puncture unfertilized frog eggs or toad eggs, causing parthenogenesis, and obtained toads without a grandfather. ^[1]

(A) sporadic parthenogenesis: sporadic parthenogenesis refers to the decline of certain insects under normal conditions

(I) Equal cleavage parthenogenesis: namely

1. different from

Liu Kun, a postdoctoral fellow in reproductive biology at the University of Kentucky in the United States, said, "Why sexual reproduction?" She said that single-celled organisms, such as bacteria, multiply by simple divisions, and they know nothing about the existence of "bisexuals." Lower organisms, such as leech, can generate new individuals by "sprouting". How fast and easy this type of asexual reproduction is, it's like a person grows a finger, and then the finger falls off by itself, and grows into a villain, completely eliminating the trouble of "targeting". So, why does sexual reproduction appear in evolution and become the mainstream of evolution?

Liu Yan said that most theories now believe that sexual reproduction can produce more

Females have only half of their mother's genes in their eggs.

Frog eggs can also be parthenogenetic through special physical stimulation.

1: in

Sexual reproduction is obviously very beneficial, but there are also many problems.

First, sexual reproduction consumes a lot of energy. Adding sexual intercourse itself is already more troublesome than split reproduction, not to mention "finding a spouse." If the density of the same species is high, it is okay to say that a creature like a humpback whale that has not seen a few hundred kilometers will be troublesome. So humpback whales have been "singing" in order to know themselves. If it's just consuming energy, this process is dangerous because not only your partner can receive your signal, but also predators. Whether it is a bird song, a frog call, or a cicada noise, the small animals show their throats with their longing for the joy of the clouds and rain, but they often attract wild cats and hunting pheasants.

Finding the opposite sex is troublesome enough, and competing with the same sex consumes more energy. Whether it is the iron head of the antelope or the grouse racing feathers, it is only for the opportunity to continue the offspring. If such courtship competition eventually evolves into cumbersome bodily organs, such as the irritated big horns of the Irish moose or the long tail feathers of a peacock, then such creatures themselves will be threatened by arrest.

For social creatures, sexual reproduction seriously threatens "stability and unity." Needless to say, the constant emotional disputes among human beings, even the worker bees and worker ants who seem to be "safe and secure" may rise to threaten the queen in order to be able to reproduce. One more thing, you may not notice that if a child with sexual reproduction produces another half of her own genes, how can a "clone" look like yourself?

There is a huge "degradation driving force" in the creatures in nature. Simply put, as long as the environment allows, it can be simple and simple, and lazy. If there are no natural enemies on the ground, birds will give up the ability to fly. Similarly, animals in many habitats return to the state of "bearing without mating", that is, "parthenogenesis". For example, if the female aphid has sufficient food, it will seize the time for parthenogenesis, and it can reproduce for several generations. It will not produce female and male individuals until the end of autumn and early winter.