1, fission propagation

In single-celled organisms, this mode of reproduction is more common. For example, paramecium, amoeba, euglena and bacteria all divide and reproduce.

2. Bud grafting propagation

Yeast and hydra (when the environment is bad, hydra also has sexual reproduction. ) often bud and reproduce.

3. Spore reproduction

Generally speaking, lower plants and fungi reproduce in this way. Such as Adiantum, Penicillium and Aspergillus.

4. Nutritional reproduction

Potato tubers, thistle roots, strawberry creeping branches and begonia leaves can all germinate, and these buds can form new individuals.

5. Tissue culture

Plant cells are omnipotent. According to this theory, plant propagation can be completed by using plant tissue culture technology.

6. Cloning

A group of cells or individuals with the same genetic structure formed by asexual reproduction of precursors. For gene cloning, it refers to multiple copies of a gene after repeated amplification.

sexual reproduction

1, zygotic reproduction

The sexual reproduction of single-celled organisms is carried out directly by individuals, which is called zygotic reproduction; Groups of multicellular organisms and unicellular organisms undergo fusion or parthenogenesis from specialized haploid cells, namely gametes.

2. Gametogenesis

Gametes are germ cells produced by individual plants, and they need to cooperate with each other to continue their life history. If they don't find the right gamete within a certain period of time, they will die.

3. Parthenogenesis

Parthenogenesis: Some animals do not need males to participate in reproduction, but females lay eggs.

4. Larval reproduction

Paedogenesis: The reproductive organs of animals can produce sperm or eggs for sexual reproduction after the larvae grow into adults.

5. Polyembryo reproduction

Polyembryo phenomenon: an egg can produce two or more embryos and develop into multiple individuals, which is called polyembryony phenomenon.

Extended data

Advantages of asexual reproduction

1, shortening the plant growth cycle;

2. Keep the excellent characters of crops and add some new advantages;

3. Increase crop yield.

disadvantaged

Many people have sexual reproduction and are prone to death due to bacterial invasion.

sexual reproduction

The wide variation of gene combination in sexual reproduction can increase the ability of offspring to adapt to natural selection. Sexual reproduction can promote the spread of favorable mutations in the population. Sexual reproductive species have diploid stages in their life cycle. Diploid species have two copies of each gene, and one copy is in functional standby state. Based on the above reasons, sexual reproduction has accelerated the process of evolution.

Baidu encyclopedia-sexual reproduction

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