Content
- What does the alternation of generations consist of?
- Advantages of generational alternation reproduction
- Examples of alternating generations in animals
- Reproduction of bees and ants
- Crustaceans with generational alternation reproduction
- Jellyfish reproduction
- Breeding insects by alternating generations
THE generational alternation reproduction, also known as heterogony, is an uncommon strategy in animals and consists of alternating a cycle with sexual reproduction followed by another asexual cycle. There are animals that have sexual reproduction but, at a certain point in their life, manage to reproduce asexually, although this does not mean that they alternate one type of reproduction with another.
Alternation of generations is more common in plants, but some animals also practice it. Therefore, in this article by PeritoAnimal, we will delve into this type of reproduction and give some reproduction examples per alternation of generations in animals who practice it.
What does the alternation of generations consist of?
Reproduction by generational alternation or heterogony is a type of very common breeding in simple flowerless plants. These plants are bryophytes and ferns. In this reproductive strategy, sexual reproduction and asexual reproduction are alternated. In the case of plants, this means that they will have a sporophyte phase and another phase called gametophyte.
During the sporophyte stage, the plant will produce spores that will give rise to adult plants genetically identical to the original. At gametophyte phase, the plant produces male and female gametes that, when they join other gametes from other plants, will give rise to new individuals with different genetic load.
Advantages of generational alternation reproduction
Reproduction by alternation of generations accumulates the advantages of sexual and asexual reproduction. When a living being reproduces through a sexual strategy, it gets its offspring to have a very rich genetic diversity, which favors the adaptation and survival of the species. On the other hand, when a living being reproduces asexually, the number of new individuals that appear is infinitely greater in a short period of time.
Thus, a plant or animal that reproduces by alternating generations will achieve a genetically rich generation and a highly numerical one, together increasing your chances of survival.
Examples of alternating generations in animals
Generational alternation breeding in invertebrate animals such as insects is perhaps the most common and abundant example, but jellyfish breeding can also follow this strategy.
Next, we'll show the types of animals with generational alternation reproduction:
Reproduction of bees and ants
The reproduction of bees or ants occurs by alternating generations. These animals, depending on the vital moment where they find themselves, they will reproduce through a sexual or asexual strategy. both live in a eusociety or real society, structured in castes, each of which plays a unique and fundamental role. Both ants and bees have a queen that copulates once in their lifetime, just before a new hive or anthill forms, storing the sperm inside her body in an organ called a spermtheca. All of her daughters will be the result of the union of the queen's eggs and stored sperm, but at a certain point, when society is mature (approximately one year in the case of bees and four years in the case of ants), the queen will lay unfertilized eggs. (asexual reproduction by parthenogenesis) that will give rise to males. In fact, there are known species of ants in which there are no males, and reproduction is 100% asexual.
Crustaceans with generational alternation reproduction
You genus crustaceans Daphnia have alternation reproduction. During spring and summer, when environmental conditions are favorable, daphnia reproduce sexually, giving rise only to females that develop inside their bodies following an ovoviviparous strategy. When winter begins or when there is an unexpected drought, females produce males by parthenogenesis (a type of asexual reproduction). The number of males in a population of daphnia will never be greater than that of females. In many species, the male morphology is unknown as it has never been observed.
Jellyfish reproduction
The reproduction of jellyfish, depending on the species and the phase where they find themselves, it will also occur by alternation of generations. When they are in the polyp stage, they will form a large colony that will reproduce asexually, producing more polyps. At a certain point, the polyps will produce small free-living jellyfish that, when they reach adulthood, will produce female and male gametes, carrying out sexual reproduction.
Breeding insects by alternating generations
Finally, the aphid Phylloxera vitifoliae, reproduces sexually in winter, producing eggs that will give rise to females in spring. These females will reproduce by parthenogenesis until temperatures drop again.
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