Without the combination of germ cells, the mother directly produces a new individual reproductive model.

1, fission propagation

There is an organism that splits directly into two new individuals. The two new individuals are basically the same in size and shape. )

For example: single-celled organisms such as bacteria, paramecium and amoeba.

2. Germination and propagation-Hydra and yeast

3. Spore propagation-Examples: Rhizopus, Aspergillus

The mother produces spores, which are small cells specially used for reproduction through cell division. Spores germinate and grow into offspring and new individuals.

4. Nutritional reproduction

After the vegetative organs of the mother leave the mother, they form new offspring through "regeneration". Strawberries, potatoes, sugar cane ...

(2) Sexual reproduction

Sexual germ cells (also called gametes) produced by parents become fertilized eggs (such as fertilized eggs) through the combination of germ cells (such as eggs and sperm), and then the fertilized eggs develop into new individual reproductive methods.

2.？ 1.？ 1 conjugation refers to some fine

When bacteria, green algae and protozoa have sexual reproduction, these two kinds of cells are interdependent.

Zygote is formed by protoplast fusion and zygote.

The reproductive mode in which fertilized eggs develop into new individuals. The joining of bacteria is

Two kinds of bacteria transmit genetic information in one direction through a temporary protoplasmic bridge.

Rest is the most primitive zygotic reproduction. The algae plant Spirogyra is jointed.

In the process of reproduction, protoplasts in cells can contract to form gametes, and male gametes can form gametes with female gametes.

Amoeba-like movement and female gamete fusion form zygote, which is suitable in the environment.

In due course, it will sprout into a new plant. Protozoa ciliates are zygotes.

Colonization was achieved through nuclear fusion.

2.？ 1.？ Gametogenesis is the advanced development of sexual reproduction.

Stage refers to the formation of new gametes through fertilization of bisexual gametes.

Individual reproductive model.

According to the degree of difference between male and female gametes, gamete reproduction can be divided into: ①

Homogamy: the shape, size, structure and transport of bisexual gametes.

Primitive reproductive types with the same mobility. Like Chlamydomonas. ② Intermarriage

Androgyny reproduction: The shape and structure of hermaphroditic gametes are the same, but their sizes are different.

Same. Haematococcus truthfully. (3) Egg matching: the hermaphroditic gamete is large.

There are obvious differences in size, shape, structure and athletic ability. Female mating

Children are called eggs, and male gametes are called sperm.

According to the different fertilization and development modes, gamete reproduction can be divided into:? ①

Oviposition ability: refers to the female of most animals after ovulation, whether it is

In-vivo fertilization or in-vitro fertilization, embryo development is in the external environment.

A complete reproductive model. ② viviparous: refers to some animals.

Most of the process of embryo development has been completed in the mother, and it is young after ovulation.

A reproductive model in which the body is produced very quickly from the eggshell. Such as invertebrate circles

White-spotted horned shark (horned shark? Acanthias) and so on. ③ Fetus

Viviparous: In some animals, the embryonic development is completely in the mother's body.

A reproductive mode that occurs when an embryo develops into a larva. read more

In higher mammals. But there are similar phenomena in plants, such as a kind of

After the seeds of mangrove plants mature, they neither leave the mother nor go through dormancy period.

Sleep, but directly germinate in the maternal fruit, by absorbing maternal nutrients,

Only when they grow into embryos can they live independently from their mothers.

2.？ Parthenogenesis refers to the continued existence of biological individuals without need.

The genetic material or sperm to be fertilized participates in fertilization, but it is not transmitted continuously.

Reproduction methods of offspring.

2.？ 2.？ 1 eggs produced by parthenogenetic females can be fertilized without fertilization.

The reproductive mode of developing into offspring is called parthenogenesis (parthenogenesis 2

According to the frequency of appearance, it can be divided into two types:? ① Parthenogenesis

(Parthenogenesis): refers to some animals (such as silkworms) in.

Under normal circumstances, bisexual reproduction occurs, but occasionally unfertilized eggs develop into

The phenomenon of new individuals. ② Parthenogenesis (Parthenogenesis 2

Esis): refers to some insects in the whole life history or in a certain generation, because there is no

There are males or only a few infertile males, and all the eggs are gone.

The phenomenon of fertilization and normal development into new individuals. Can also be divided into permanent.

Parthenogenesis, periodic parthenogenesis, larval reproduction, geographical parthenogenesis

Four types of colonization.

2.？ 2.？ 2 gynogenesis gynogenesis refers to the dependence on eggs.

From one's own nucleus to individual reproductive behavior. Sperm only stings.

Stimulate the development of eggs, produce complete offspring without providing genetic material.

The female part only has the characteristics of the female mother. For example, vertebrate crucian carp (Car2

Assis? auratus？ The gynogenesis of allogynogenetic crucian carp.

2.？ 2.？ 3 hybrid reproduction (hybridization) refers to the non-.

A breeding method for crossbreeding intraspecific or interspecific individuals with the same ploidy to produce offspring,

The offspring are all females, but they have paternal traits, and the genetic material of sperm is only ginseng.

With the development of the first generation, it will not be passed on to future generations. Only natural hybridization

In fish, such as CYPRINIDAE? Proteoid complex

Body.

Contrast angle asexual reproduction and sexual reproduction

Whether there are gender differences in germ cells.

The union of hermaphroditic germ cells is usually

Is it beneficial to keep parental traits?

The living ability of future generations is strong and weak.

Can't promote the evolution and development of the whole species.

Long-term impact on racial decline and prosperity

Breeding speed is fast and slow.

The emergence of new individuals? Direct maternal production, zygote development production.

Three special reproductive types

3.？ 1 proliferation of acellular organisms/proliferation of acellular biological viruses

This is called viral proliferation, which is viral genome replication.

And the result of expression. Viruses are infected by living cells, in their own nucleic acids.

Under the guidance of, using host cells to provide a variety of proliferation-related

Self-replicating factor, its replication process can generally be divided into adsorption,

Invasion and shelling, macromolecular synthesis, assembly and release.

3.？ Apomixis plants do not experience the fusion of male and female gametes.

The combination of embryo and seed is called apomixis.

Although there are similar phenomena in animals, due to the fertilization mode of plants,

Because of its particularity, apomixis of plants is considered as a special type.

Elaboration of reproductive model. Can be divided into two types:? ① Haploid apomixis

Reproduction: embryo sac is formed by normal meiosis of embryo sac mother cells.

Yes, but the egg cells develop directly into embryos without fertilization, such as corn.

Apomixis; Or directly develop into embryos from helper cells and antipodal cells, for example.

Apomixis in rice. ② Diploid apomixis refers to some plants.

The embryo sac of plants is composed of sporozoites and embryo sac mother cells without meiosis.

Or sperm cells in nucellar cells, egg cells and embryo sacs.

Cells and antipodal cells are diploid. Apomixis is like onion.

3.？ 3 animal polyembryonic finger 1.

An egg can produce two or more embryos and develop into a normal new individual.

The way of reproduction. It is more common in some parasitic bees of Hymenoptera. Insect polyembryony

When the fertilized egg matures and divides, the polar body does not disappear, but concentrates on the egg.

One end continues to divide, gradually forming a layer of nourishing membrane wrapped around the embryo, and the embryo is connected.

Hypertrophic membranes absorb needed nutrients from the host. Not just insects,

In polyembryony, there are similar phenomena in vertebrates, such as some high

Identical twins or multiple births in other animals.

Polyembryo reproduction is a special type of reproduction. On the one hand, it is universal.

Reproduction through germ cells belongs to sexual reproduction; But on the other hand,

Polyembryo reproduction is that an early embryo produces two embryos through asexual reproduction.

Or more embryos, but also contains asexual reproductive factors.

3.？ Quasi-sexual reproduction of fungi, some filaments do not produce sexual spores.

Fungi, such as Aspergillus nidulans? nidulans)？ , can't be reduced.

Number division, nuclear fusion and chromosome exchange in mycelium cells.

Then the reproductive process of producing offspring is called quasi-sexual reproduction (pa2

Straight? Reproduction). Quasi-sexual reproduction is a special reproductive prescription.

Type A, with nuclear fusion, chromosomes and genes similar to sexual reproduction.

Exchange, separation and recombination, and can form recombinant; But its genetic recombination

Not by meiosis of germ cells, but by mitosis of somatic cells.

In the process of division, it is achieved through the irregular exchange and reduction of chromosomes. but

However, quasi-sexual recombinant cells and general vegetative cells have no shape.

The difference is that it is not produced in special capsules, which is produced by quasi-sexual reproduction.

The fundamental difference between sexual reproduction.