What is Asexual reproduction? Asexual reproduction is the formation of offspring from a single parent.
The offspring are identical to the parent.
Types of asexual reproduction.
- Binary fission in amoeba.
- Spore formation in Rhizopus.
- Budding in yeast.
- This involves the division of the parent organism into two daughter cells.
- The nucleus first divides into two and then the cytoplasm separates into two portions
- Binary fission also occurs in bacteria, Paramecium, Trypanosoma and Euglena.
Spore formation in Rhizopus
- Rhizopus is a saprophytic fungus which grows on various substrate such as bread, rotting fruits or other decaying organic matter.
- The vegetative body is called mycelium which has many branched threads called hyphae.
- Horizontal hyphae are called stolons.
- Vertical hyphae are called sporangiophore.
- The tips of sporangiophore become swollen to form sporangia, the spore bearing structure.
- Each sporangium contains many spores.
- As it matures and ripens, it turns black in colour.
- When fully mature the sporangium wall burst and release spores which are dispersed by wind or insects.
- When spores land on moist substratum, they germinate and grow into a new Rhizopus and start another generation.
Spore formation in ferns
- The fern plant is called a sporophyte.
- On the lower side of the mature leaves are sari (Singular: sorus) which bear spores.
Budding in Yeast
- Budding involves the formation of a protrusion called a bud from the body of the organism.
- The bud separates from the parent cell, in yeast budding goes on so fast and the first bud starts to form another bud before the separation.
- A short chain or mass of cells is formed.
REPRODUCTION IN PLANTS AND ANIMALS
HUMAN DISEASES (PARASITIC DISEASES)
HUMAN DISEASES – BACTERIAL DISEASES