Increase in the number of individuals of their species -the most important task of any organism. That is why, along with sexual reproduction, asexual appeared. Plants, in their own way, adapted to effective spreading, using the organs of their body for this. What is the biological significance of asexual reproduction? What are the advantages and disadvantages of this method?
What is asexual reproduction?
One of the goals of the existence of a living organism -reproduction of their own kind. To solve this problem, plants, animals, bacteria and other representatives of the biological world have found their ways to increase the number. Knowingly multiplication is attributed to one of the parameters of all living things, along with growth, energy exchange, constancy of the internal environment, and so on.
Sexless reproduction is the way in whichparticipation of germ cells is not required. Gametes play an exceptional role in the formation of a new genetic material of the embryo, however, it is not always possible to switch to the sexual mode of reproduction. What is the biological significance of asexual reproduction?
For some organisms, for example, bacteria -this is the only way to increase the population size. For the rest of the representatives of the animal and plant world asexual and sexual reproduction are needed equally. If the former is used for a quantitative increase in the number, then the second is for a qualitative (that is, a change in the genetic material).
Types of Asexual Reproduction
Playing your own like with great speed- this is the biological significance of asexual reproduction of organisms. This type of reproduction is more ancient, and therefore the peak of its dominance falls on low-developed organisms. Below are the species of asexual reproduction that can occur in different taxonomic groups.
- Binary division.This type of reproduction is characteristic of most prokaryotes and protozoa. The cell forms a transverse septum that divides it in half, thereby forming two daughter cells.
- Shizogony.This method can be considered an improved version of binary division, when several children develop from one cell at once. First, the nucleus is divided, and then the cell itself. This type of reproduction can be observed in the life cycle of sporovikov (for example, malarial plasmodium), as well as some algae.
- Pocification.Despite the simplicity of binary division and schizogony, not for all organisms, these methods of reproduction can be effective. For such primitive multicellular animals as the intestines, budding is characteristic - the formation of a new organism in the form of an outgrowth, which is first connected to the parental individual, and then detached. If such a "kidney" does not detach, colonies from several organisms are formed. Soil is also characteristic of yeast.
- Fragmentation.This type of reproduction is based on the body's ability to regenerate. It is characteristic for planarians, nemertines, sponges, some filamentous algae. With mechanical damage, the parent can be divided into several parts, each of which gives rise to a new organism.
- Sporulation, or sporulation.The most progressive type of asexual reproduction, because during the formation of a dispute, genetic information is exchanged. As a result, the genotype of offspring differs somewhat from that of the parent. Spore formation can be observed in fungi, algae, horsetails, ferns, mosses, and mosses.
What is the biological significance of asexual reproduction of plants?
The kingdom of the plant is conditionally divided into spore andseminal. The first include mosses, horsetails, plains, ferns, and to the second - gymnosperms and angiosperms. Asexual reproduction of spore plants is mainly in the formation of spores. In gymnosperms and angiosperms, spore formation remained as an intermediate stage in the appearance of gametes (microspores and megasores). Reproduction with the help of the organs of the body is the biological significance of asexual reproduction in plants.
Vegetative reproduction is characteristic only forhighly developed representatives of the flora, and it is also the only type of asexual reproduction. In spore, this method is extremely rare. Here, in fact, is one more aspect, what is the biological significance of asexual reproduction in plants.
How is the reproduction of individuals vegetatively?
- Modifications of the stem.This includes bulbs, corms, rhizomes, stolons, tubers, mustaches. On such organs of the plant, rudimentary buds are formed, from which new shoots grow. This method of reproduction can be found in tulips, narcissus, onions, blackberries, iris, strawberries, potatoes, etc.
- Root tubers (root crops). These organs are subordinate roots in which nutrients are stored. Kneaker breeds violet, Jerusalem artichoke, dahlia.
- Cuttings.A stalk is any part of the stem that contains at least one node with subordinate buds. Sometimes just a sheet without a stem is enough for reproduction. Examples of plants: begonia, fuchsia, dracaena, etc.
The biological role of asexual reproduction of plants
The process of gamete formation depends on the set offactors. Often asexual reproduction can be more effective, because it can be done without gametes. For spore plants, this is the main component of the life cycle. For seed, this is vegetative reproduction, in which the number of individuals can be easily increased.
What is the biological significanceasexual reproduction? This is not only speed, but also ease in the process. If optimal conditions of the environment are necessary for sexual reproduction, the maturity of the plant itself, the asexual can be observed almost at any time of the life of the individual.
However, vegetative reproduction has its ownshortcomings. For example, with this type of reproduction there is no exchange of genetic information. This means that the plant does not adapt in a number of generations to new environmental conditions, and this can lead to a loss of the population of the clones obtained.
Application of asexual reproduction of plants by humans
The reproductive process is actively used ineconomic activity. Vegetative reproduction of plants allows sowing large tracts of land with potatoes, onions, beets, carrots, strawberries, strawberries, etc.
Also vegetative propagation allows to increase the amount of forage, vegetable, ornamental crops, enhance resistance of plants to adverse environmental conditions via inoculation.
