What is the function of Gemmae cups?
What is the function of Gemmae cups?
The main function of the Gemma cup is vegetative reproduction. The Gemma is a small cup-shaped cell found on the thalli of bryophytes such as mosses and liverworts. The Gemma cells separated from the parent and develop into a new individual.
Where would you find a Gemmae Cup?
A small receptacle or cup on upper surface of bryophytes in which gemmae are produced from which they are splashed out of and dispersed by rain drops.
Do mosses have Gemmae cups?
These cups are located at the apex of the leafy moss and function in reproduction. The moss makes little discs of plant tissue inside the cups called gemmae. These gemmae are moved away from the parental plant via a splash-cup dispersal mechanism.
What organism produces Gemmae cups?
It is often associated with human activity. This is the only native genus of thalloid liverworts that produces gemmae cups.
Can bryophytes reproduce asexually?
Asexual reproduction s. l. and the formation of asexual diaspores therefore is a remarkable feature and widespread in bryophytes. In nearly no other plant group asexual reproduction is so important than in bryophytes. A great number of bryophyte species, especially dioicous ones, reproduce exclusively asexually.
What is the meaning of Gemmae?
A gemma (plural gemmae) is a single cell, or a mass of cells, or a modified bud of tissue, that detaches from the parent and develops into a new individual. This type of asexual reproduction is referred to as fragmentation. It is a means of asexual propagation in plants.
What are the two main classes of bryophytes?
hornwort , livewort and mosses are the tree main classes of bryophytes.
Is Gemma a word?
Gemma is a name of Latin origin, meaning “gem” or “gemstone”. Its popularity peaked in the United Kingdom during the 1980s. It was the third most popular female name in 1984 in the UK.
What is meant by Metagenesis?
: alternation of generations in animals especially : regular alternation of a sexual and an asexual generation.
What is Metagenesis give an example?
The definition of metagenesis is the reproduction cycle of an organism that alternates between sexual and asexual generations. An example of metagenesis is the reproduction cycle of a cnidarian. (biology) The production of sexual and asexual organisms in alternate generations.
Where is Metagenesis found?
Metagenesis can be seen in physalia. Metagenesis is a process which takes place in algae and primitive plants. Here the plant is able to perform both sexual and asexual reproduction.
What is Metagenesis explain with reference to the example you have studied?
Metagenesis is referred to the phenomenon of alternation of generation shown by cnidarians which exhibit both forms- polyps and medusae . Polyps produce medusae asexually and medusae form the polyps sexually (e.g., Obelia). Answer verified by Toppr. 1715 Views.
What is Metagenesis in cnidaria?
Some cnidarians exist in polyp and medusa forms. Such cnidarians show metagenesis. It is the phenomenon of alternation of generations in which polyps produce medusae asexually and medusae produce polyps sexually. Metagenesis is observed in Obelia.
What is Metagenesis in zoology?
metagenesis The occurrence, during the life cycle of an organism, of two types of individual, both diploid, both of which reproduce, one sexually and the other asexually. The term is sometimes used loosely (but incorrectly) as a synonym for the alternation of generations. A Dictionary of Zoology MICHAEL ALLABY.
What is Metagenesis in obelia?
METAGENESIS The life cycle of Obelia represents a remarkable example of alternation of generation where the asexual and sessile phase of Obelia reproduces asexually by budding and gives rise to sexual and free-swimming medusa. This phenomenon of alternation between two diploid phases is termed as metagenesis.
What is polymorphism in cnidaria?
Polymorphism refers to the occurrence of structurally and functionally more than two different types of individuals within the same organism. It is a characteristic feature of Cnidarians, particularly the polyp and medusa forms, or of zooids within colonial organisms like those in Hydrozoa.
What is polymorphism in obelia?
The phenomenon of occurrence of an individual in two or more distinct morphological and functional forms. It occurs in the same species of an individual. Each individual member of Coelenterates is known as Zooid and they often units to form a colony which acts as a single unit (individual). …
What is Metagenesis Class 11?
Answer: Metagenesis is the phenomenon in which one generation of certain plants and animals reproduce asexually, followed by the sexually reproducing generation. Coelenterates exhibits metagenesis (e.g., Obelia) where polyp form alternates with medusa in its life cycle.
What are the two stages of Metagenesis?
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.
What is the role of feathers Class 11?
The foremost and the most important function of a feather is that they help in insulation. It means that they prevent the loss of heat from the body. Therefore, feathers help in thermoregulation or control the temperature of the organism’s body.
What is alternation of generation in plants Class 11?
Plants alternate between the diploid sporophyte and haploid gametophyte, and between asexual and sexual reproduction. Therefore, the life cycle of plants is known as alternation of generations. The plants’ life cycle in one of the two generations is dominant over the other.
What is Haplodiplontic life cycle?
The plant life cycle alternates between haploid and diploid generations. Fertilization gives rise to a multicellular diploid sporophyte, which produces haploid spores via meiosis. This type of life cycle is called a haplodiplontic life cycle (Figure 20.1).
Is 2n a Sporophyte?
The sporophyte is a diploid (2n) spore-producing plant. When reproducing, the sporophyte produces specialized leaves called sporophylls.
Why does Fern reproduction require two generations?
The fern life cycle requires two generations of plants to complete itself. This is called alternation of generations. One generation is diploid, meaning it carries two identical sets of chromosomes in each cell or the full genetic complement (like a human cell). A fern’s spores don’t grow into leafy sporophyte.
How do you tell if a fern is male or female?
Scientists previously knew that the factor that determines which sex a specific fern will end up as is a hormone called gibberellin. If the hormone is present in large enough quantities as the plant develops, the fern usually becomes a male, and if it isn’t, it becomes a female.
Do Ferns reproduce asexually?
Most ferns reproduce through the alternation of generations, alternating successive generations of sexual and asexual forms. The second form of asexual reproduction occurs by spores. These form on the undersides of the leaves in clusters of spore cases called sporangia, or sori (singular, sorus).
How do ferns reproduce sexually?
Most ferns reproduce sexually, and that involves meiosis and fertilisation. If the sperm do manage to get to an egg, fertilisation occurs, and that is where the two, the sperm and egg come together. It doubles the number of chromosomes, and that gives rise to a whole new typical fern plant again, and the cycle repeats.
Do Boston ferns have spores?
Although humidity does help, the Boston fern’s potting soil should be well-drained. It does not produce viable spores, so the Boston fern must be propagated vegetatively by divisions of the crown or by rooting runners (underground stolons).
How do Mosses reproduce sexually?
Moss sexually reproduces by transmitting sperm (in the presence of water) from the male plant to the female. The zygote forms a stalk (called seta) which hold spores in a small pod at its top.