Tables relating to reproduction and development
Comparison table between asexual reproduction and sexual reproduction
Asexual reproduction Sexual reproduction
There is no there is no formation of sexual reproductive cells The formation of sexual reproductive cells
Goes through meiosis without going through meiosis
Goes through fertilization without going through fertilization
Appeared early in evolutionary history, lower Etc., primitive mode of reproduction. Common among lower organisms and plants. It appears late in evolutionary history. The higher mode of reproduction of higher plants and animals.
Without genetic recombination. in the absence of genes In the event of a mutation, the genetic material of the offspring is exactly the same. With genetic recombination, the genetic material of the offspring is largely changed and the variation is large.
Methods includedennent: reproduction by fission, reproduction by budding, sporulation and vegetative reproduction (grafting, cuttings, layering), etc. Higher plants use double fertilization and higher animals use ordinary fertilization
Application: Quick. propagation of excellent varieties of fruit trees by grafting and other methods, plant tissue culture, etc. Application: crossing < /p>
Commonalities: Both increase the number of offspring, and both have inheritance and variation
.[1] Types of reproduction:
Ⅰ. Asexual Reproduction:
1. Concept: A method of reproduction that produces new individuals directly from the mother without a combination of germ cells.
Note: Asexual reproduction can produce germ cells, but new individuals should not be formed without the combination of male and female reproductive cellss.
2. Category:
p> Concept Example: Schizophrenia is a method of reproduction in which a mother body divides into two daughter bodies, such as amoebae and bacteria , which reproduce by spores (a type of asexual reproductive cell). form new individuals of Rhizopus and Penicillium without the combination of the two. Buds are produced by the mother body at a certain place. The buds fall from the mother body as they grow, new individuals are formed, such as yeast and. polyps. Vegetative reproduction produces new individuals from the vegetative organs (roots, leaves, stems) of the plant. Methods of breeding new individuals include strawberry runners, thistle roots, begonia leaves and potato tubers.
3. Several special reproduction methods
(1) In vitro fertilization
In vitro fertilization, after the eggsIf fertilized have developed outside the body for some time, the embryos are transplanted into the uterus to continue development.
Essence: It belongs to normal human reproduction, it mainly changes the place of fertilization.
Move the somatic cell nucleus into the enucleated egg cell, transplant the combined egg cell into the uterus, and gradually develop into a new individual
Essence: Cultivation and reproduction of. somatic cells, asexual reproduction
(3) Group.Tissue culture
①Somatic cell tissue culture
When plant somatic cells are isolated from the body, they form gradually a new plant by cell division and cell differentiation on tissue culture medium
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Essence: It belongs to asexual reproduction. Its principle is the totipotency of plant somatic cells
②In vitro anther cultureo
Mature pollen is obtained directly. grown in tissues without fertilization. It is a haploid plant
Essence: Sexual reproductive cells are grown into new individuals in vitro, which belong to sexual reproduction. viruses
The mode of reproduction of viruses is replication, which should be classified as asexual reproduction
Ⅱ Sexual reproduction:
1. Concept: refers to . combination of two sex cells to form a zygote, which then forms a new individual.
2. Category:
Examples of Reproductive Species Names Name Concepts Sexual Reproduction Asogametic Reproduction Two gametes that combine to form a zygote, lower animals of the same shape and size same size. Plants, such as algae and fungi, combine to form a zygote through anisogametic reproduction. The two gametes are of different shapes and sizes, one is slightlynt bigger and the other. smaller. Green algae and protozoa are formed by the combination of eggs and ovules. ** * Parthenogenesis in higher animals and higher plants. In animals that undergo sexual reproduction, eggs develop independently into offspring without fertilization. , aphids, water fleas, dandelions,
3. The process of sexual reproduction of angiosperms:
① The formation of pollen grains and cysts:
< p> Note: 2 of the same reproductive cells are formed ***, whose genetic composition is exactly the same② The formation of the embryo sac, egg cell and polar nucleus:
③ Double fertilization. process (a phenomenon unique to angiosperms)
4. Comparison of sexual reproduction and asexual reproduction
Asexual reproduction project Differences in sexual reproduction Germ cells can produce cells germinals (such as spores), but germ cells are not produced by the combination of germ cells. Generally, germ cells are produced by the combination of hermaphrodite germ cells, and the offspring will essentially retain the mother's traits, with little else added. variation.This is a breeding method that maintains the excellent traits of the parents.The offspring will have the heritability of both parents, and the variability is strong, which is not conducive to maintaining the adaptability of the offspring with the traits of the parents. Similarities between weak and strong