The process by which organisms produce new individuals is called reproduction. Let us learn the difference between asexual reproduction, which does not involve males and females, and sexual reproduction, which involves males and females.
Basic Knowledge
Asexual reproduction: A method in which one parent divides or produces a new individual.
① Division: The parent's body divides into two(paramecia and crescent algae).
② Budding: Part of the parent's body swells and becomes a new individual(hydra and yeast).
③ Vegetative reproduction: Plants produce new individuals from roots, stems, or leaves(potatoes, sweet potatoes, strawberry runners, taro, and others).
④ Spore reproduction: New individuals develop from spores(ferns, mosses, molds, and mushrooms).
In asexual reproduction, offspring are genetically identical to the parent(clones).
Sexual reproduction: A method in which males and females produce reproductive cells(sperm and eggs), which unite(fertilization) to produce a new individual.
In animals, an egg andsperm undergo fertilization; in angiosperms, an egg cell andsperm cell undergo fertilization. The fertilized egg repeatedly divides and develops into an individual.
Asexual reproduction(Reproduction in which offspring are produced from one parent without the involvement of males and females)
Sexual reproduction(Reproduction in which male and female reproductive cells unite to produce offspring)
Reproductive cell(A special cell for reproduction. Eggs, sperm, egg cells, and sperm cells)
Fertilization(The union of an egg(egg cell) and sperm(sperm cell))
Fertilized egg(A single cell produced by fertilization. The beginning of a new individual)
Vegetative reproduction(Asexual production of a new individual by a plant from part of its body)
Further Exploration (Background and Significance)
Differences and significance of asexual and sexual reproduction:
・Advantages of asexual reproduction: Offspring can be produced quickly, in large numbers, and reliably(if the same environment is suitable, this is advantageous).
・Disadvantages of asexual reproduction: Because there is no genetic diversity, organisms are vulnerable to environmental changes and diseases. There is a risk that the entire population may become extinct at once.
・Advantages of sexual reproduction: It can produce varied offspring different from the parents. This increases the ability to adapt to environmental changes and diseases and drives evolution.
・Disadvantages of sexual reproduction: A partner is needed and the cost is high.
In animal development, the fertilized egg repeatedly divides(cleavage) and changes through the morula→blastula→gastrula→neural embryo→fetus stages. In plants: fertilized egg→embryo→seed→seedling→individual.
Strawberries and potatoes are examples that use both asexual(vegetative) and sexual reproduction. In agriculture, asexual reproduction is used to mass-produce crops of the same quality as clones, while sexual reproduction is used to develop new varieties.
- Asexual reproduction = offspring from one parent(division, budding, vegetative reproduction, spores)
- Sexual reproduction = fertilization of male and female reproductive cells
- Asexual reproduction = offspring are genetically identical to the parent(clones)
- Sexual reproduction = varied offspring = stronger adaptation to environmental changes
- Animal reproductive cells = eggs and sperm
- Angiosperm reproductive cells = egg cells and sperm cells
- A fertilized egg divides and develops into an individual = development
- Potatoes and sweet potatoes are examples of vegetative reproduction
Points to Note (Often Confused)
① Offspring produced by asexual reproduction are genetically identical to the parent. ② Offspring produced by sexual reproduction are different from the parents(they inherit half of their genes from each parent). ③ Spore reproduction occurs in ferns, mosses, and mushrooms. It is different from seeds in seed plants. ④ Potatoes sprout from “tubers(underground stems),” so this is vegetative reproduction. Although potatoes can also produce seeds, they are usually propagated vegetatively.
Practice
- What type of reproduction produces a new individual from part of the body, as in potatoes?
- State the relationship between the genetic information of offspring produced by asexual reproduction and that of the parent.
- State one advantage of sexual reproduction.