It describes an alternation in forms which occur in plants and some Protists. … The classic example is the mosses, where the green plant is a haploid gametophyte and the reproductive phase is the brown diploid sporophyte. The two forms occur together.
What is alternation of generation with diagram?
Alternation of generations is a term primarily used to describe the life cycle of plants. 2. A multicellular gametophyte, which is haploid with n chromosomes, alternates with a multicellular sporophyte, which is diploid with 2n chromosomes, made up of n pairs.
Why is it called alternation of generations?
The multicellular haploid plant structure is called the gametophyte, which is formed from the spore and give rise to the haploid gametes. The fluctuation between these diploid and haploid stages that occurs in plants is called the alternation of generations.
What is alternation of generation in Class 11?
Hint: Alternation of generation refers to the occurrence of diploid and haploid multicellular organisms, giving rise to new organisms. This process allows for both the dynamic and volatile action of sexual reproduction as well as consistence act of asexual reproduction. It is most commonly found in plants and algae.
What is alternation of generation and its types?
Alternation of generations is a type of life cycle found in terrestrial plants and some algae in which subsequent generations of individuals alternate between haploid and diploid organisms. This can be contrasted to sexual reproduction in animals, in which both haploid and diploid cells are found in every generation.
What is alternation of generation in obelia?
Obelia shows an alternation of generation between asexual and sexual forms. Polyps produce medusae asexually and medusae produce polyps sexually. Further reading: Coelom. NEET Questions Animal Kingdom.
What is alternation of generation draw Haplontic lifecycle?
Plants that undergo sexual reproduction, alternate between the haploid and diploid stages. This is known as alternation of generations. … Haplontic Life Cycle – The dominant stage is the haploid gametophyte. The diploid sporophyte is only represented by the zygote, which is diploid.
What do you mean by alteration of generation?
alternation of generations, also called metagenesis or heterogenesis, in biology, the alternation of a sexual phase and an asexual phase in the life cycle of an organism. The two phases, or generations, are often morphologically, and sometimes chromosomally, distinct.
Why gametophyte is called so?
The gametophyte is the sexual phase in the life cycle of plants and algae. It develops sex organs that produce gametes, haploid sex cells that participate in fertilization to form a diploid zygote which has a double set of chromosomes.
What is the first cell of a sporophyte generation called?
✤ The first cell in a sporophyte generation is the diploid zygote, while the first cell in the gametophyte stage is the haploid spore. ✤ In the sporophyte phase, haploid spores are formed and in the gametophyte phase, diploid male and female gametes are formed.
What is alternation of generation for Class 9?
“Alternation of generations is a type of life cycle in which subsequent generations of plants alternate between diploid and haploid organisms.”
What is alternation of generation in plants Brainly?
The multicellular haploid plant structure is called the gametophyte, which is formed from the spore and give rise to the haploid gametes. The fluctuation between these diploid and haploid stages that occurs in plants is called the alternation of generations.
What is alternation of generation in cnidaria?
Alternation of generations is a type of life cycle that switches between two forms, the asexual polyp and the sexual medusa. … Each reproduction, one form will give rise to the other.
How are generation names determined?
No official commission or group decides what each generation is called and when it starts and ends. … Baby boomers are the most well-defined of the 20th-century generations, named after the post-World War II spike in the birthrate that began in 1946.
What is alternation of generation in bryophytes?
Alternation of generations is a life-cycle involving two phases of life, which regularly alternate with each other. In Bryophytes, the first phase is the gametophytic phase, in which gametes are produced, that contain half the number of chromosomes.
What is alternation of generation in fungi?
Alternation of generations is a reproductive cycle of certain vascular plants, fungi, and protists. … Two gametes (originating from different organisms of the same species or from the same organism) combine to produce a zygote, which develops into a diploid plant of the sporophyte generation.
What are the three types of life cycle?
A life cycle is a period involving one generation of an organism through means of reproduction, whether through asexual reproduction or sexual reproduction. In regard to its ploidy, there are three types of cycles; haplontic life cycle, diplontic life cycle, diplobiontic life cycle.
What are the two phases of life cycle?
Plants have two distinct stages in their lifecycle: the gametophyte stage and the sporophyte stage. The haploid gametophyte produces the male and female gametes by mitosis in distinct multicellular structures. Fusion of the male and females gametes forms the diploid zygote, which develops into the sporophyte.
What is the alternation of generations quizlet?
A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants.
What is Sporophytic plant body?
sporophyte, in plants and certain algae, the nonsexual phase (or an individual representing the phase) in the alternation of generations—a phenomenon in which two distinct phases occur in the life history of the organism, each phase producing the other. The sexual phase is the gametophyte.
How is alternation of generations an effective way of ensuring that fit individuals survive?
-Alternation of generations is the form of sexual reproduction that algae can go through. It is through this process can the algae develop more genetic diversity which ultimately leads to one algae being “more fit” than the others which ensures the organisms survival when confronted with a threat.
What would the human life cycle be like if we have an alternation of generations assume that the multicellular diploid stage is similar in form to an adult human?
What would the human life cycle be like if we had alternation of generations? Assume that the multicellular diploid stage is similar in form to an adult human. … The multicellular diploid stage of the life cycle would not produce gametes. Instead, both males and females would produce haploid spores by meiosis.
What is Sporophytic and Gametophytic?
Both Gametophyte and Sporophyte are the two Generations of a plant. Gametophyte: Gameto means gametes and phyte means plants. The generation of plants that forms gametes is called gametophyte. Plants produce gametes with the help of their sex organs. … The generation of plants that produce spores is called sporophyte.
What is male gamete?
Gametes are an organism’s reproductive cells. They are also referred to as sex cells. Female gametes are called ova or egg cells, and male gametes are called sperm. … Each sperm cell, or spermatozoon, is small and motile.
What is meant by Gametogenesis?
gametogenesis, in embryology, the process by which gametes, or germ cells, are produced in an organism. The formation of egg cells, or ova, is technically called oogenesis, and the formation of sperm cells, or spermatozoa, is called spermatogenesis.
What is a sporophyte generation?
In plants, the sporophyte generation is that phase in their life cycle that begins with the union of two single-celled haploid gametes. This union of haploid (n) gametes results in the formation of a single-celled diploid (2n) zygote. The zygote germinates and grows by going through a series of mitotic divisions.
What is made by the sporophyte generation?
The sporophyte produces spores (hence the name) by meiosis, a process also known as “reduction division” that reduces the number of chromosomes in each spore mother cell by half. The resulting meiospores develop into a gametophyte. … The mature gametophyte produces male or female gametes (or both) by mitosis.
Which is last cell of sporophyte generation?
This zygote initiated the sporophytic generation i.e. diploid stage. Therefore, the last cells formed in the gametophyte stage are the male and female gametes because the zygote starts the sporophytic generation so it is considered a part of it.
What is alternation of generation in Pteridophytes?
Alternation of generations (also known as metagenesis) is the type of life cycle that occurs in pteridophytes and other plants. They have distinct sexual haploid and asexual diploid stages.
What is Protonema Class 11?
It is a haploid, autonomous, gametophytic stage of the moss life cycle. Complete answer: A protonema is a thread-like chain of cells that forms the gametophyte’s earliest stage of growth in the life cycle of mosses. … Moss spores germinate to form the protonema, an alga-like filamentous structure.
What is alternation of generation Brainly?
Alternation of generations (also known as metagenesis) is the type of life cycle that occurs in those plants and algae in the Archaeplastida and the Heterokontophyta that have distinct sexual haploid and asexual diploid stages. … The haploid spores germinate and grow into a haploid gametophyte.
What is the unique feature of red algae in the alternation of 3 generations?
Red algae have an alternation of generations life cycle that has an extra diploid stage: the carposporophyte. The gametophytes of Polysiphonia are isomorphic (iso- meaning same, morph- meaning form), meaning they have the same basic morphology.
What is alternation of polypoid generation?
This type of true alternation of generation is also called metagenesis. In coelenterates an asexual polypoid generation appears to alternate regularly with a sexual medusae generation. So, the correct answer is ‘Both Assertion and Reason are correct and Reason is the correct explanation for Assertion’.
Which of the following cnidarians exhibit alternation of generation metagenesis?
Those cnidarians which exist in both forms exhibit alternation of generation (metagenesis), i.e., polyps produce medusae asexually and medusae form the polyps sexually.
Is alternation of generation present in Hydra?
Hint: Metagenesis is defined as alternation of generations between the reproductive phases – sexual and asexual. Complete Answer: … Hydra shows only asexual mode of reproduction via budding. As there is no sexual reproduction, metagenesis is not possible in case of Hydra.