Gemmules are internal buds found in sponges and are involved in asexual reproduction. e.g. Spongilla . These are formed during unfavourable conditions and help in perennation and dispersal.
What is a gemmules in sponges?
An asexually produced mass of cells, which are capable of developing into a new organism or into an adult freshwater sponge is termed as a Gemmule. They are small bud-like cells, which are formed by sponges to withstand unfavourable environmental conditions.
What is the purpose of gemmules?
These so-called “gemmules” are expelled from the adult sponge and, in some marine species, serve as a normal reproductive process or, sometimes, as a means to carry the sponges over periods of unfavourable conditions when the adults degenerate; e.g., drought, temperature extremes.
What are gemmules and conidia?
Gemmule – asexual reproductive structure in sponges. Conidia – asexual reproductive structure in Penicillium.
What is a Gemmule in zoology?
gemmule. / (ˈdʒɛmjuːl) / noun. zoology a cell or mass of cells produced asexually by sponges and developing into a new individual; bud.
What is the function of Archaeocytes?
Archaeocytes. Archaeocytes are very important to the functioning of a sponge. These cells are totipotent, which means that they can change into all of the other types of sponge cells. Archaeocytes ingest and digest food caught by the choanocyte collars and transport nutrients to the other cells of the sponge.
How do sponges reproduce by gemmules?
Sponges that reproduce asexually produce buds or, more often, gemmules, which are packets of several cells of various types inside a protective covering. Fresh water sponges of the Spongillidae often produce gemmules prior to winter. These then develop into adult sponges beginning the following spring.
Are gemmules spores?
Gemmules are the specialized asexual spores formed in sponges.
Where are Archaeocytes found?
Archaeocytes (from Greek archaios “beginning” and kytos “hollow vessel”) or amoebocytes are amoeboid cells found in sponges. They are totipotent and have varied functions depending on the species.
What does porifera stand for?
The phylum name Porifera means pore-bearing. Sponges take their name from small holes that cover their bodies.
What do you understand by parthenogenesis?
Parthenogenesis is a form of reproduction in which an egg can develop into an embryo without being fertilized by a sperm. Parthenogenesis is derived from the Greek words for “virgin birth,” and several insect species including aphids, bees, and ants are known to reproduce by parthenogenesis.
Do all sponges have spicules?
Among extant sponges, only the calcareous sponges can produce calcite spicules, whereas other classes’ spicules are siliceous. Some lineages among demosponges and a few calcareans have massive calcium carbonate basal skeletons, the so-called coralline sponges or sclerosponges.
Where is conidia found?
conidium, a type of asexual reproductive spore of fungi (kingdom Fungi) usually produced at the tip or side of hyphae (filaments that make up the body of a typical fungus) or on special spore-producing structures called conidiophores.
What are gemmules and Canadian name one organism each in which these are formed?
Conidia are non-motile spores which are present at the tip of special hyphal branches called conidiophores. They are formed in Penicillium and other ascomycetes. The internal budding seen in some freshwater and few marine sponges is called gemmule formation.
How are gemmules formed?
Gemmule formation occurs in freshwater by several sponges like Spongilia and some water species such as sea sponges, figuline ficus, and various other types of poriferans. The organisms give out gemmules, which further give birth to new sponges.
What is the purpose of the Osculum?
The osculum (plural “oscula”) is an excretory structure in the living sponge, a large opening to the outside through which the current of water exits after passing through the spongocoel. Wastes diffuse into the water and the water is pumped through the osculum carrying away with it the sponge’s wastes.
