Reproduction
Reproduction is the phenomenon which involves the production of an offspring by particular individual or individuals to propagate their species. Reproduction is done during reproductive phase.
Reproduction based on the number
Unicellular organisms are single celled forms whereas multicellular organisms are made up of many cells. Depending upon the complexity of the body, reproduction in unicellular organisms is different from that of multicellular organisms.
Types of reproduction
Reproduction can be of two different types, namely, asexual reproduction and sexual reproduction.
Types of asexual reproduction
Different asexual modes of reproduction by which offspring can be produced are binary fission, budding, fragmentation, regeneration, vegetative propagation, spore formation etc.
1) Binary fission: It involves the longitudinal or transverse splitting of an organism into two equal halves which develop into two separate individuals.
3) Budding: This is a form of asexual reproduction which involves development of small mass of cells as protuberances on the parental body to give rise to new structures called as buds.
4) Fragmentation: It involves breaking of parent organism into two or many fragments. Each fragment develops into an individual organism. Fragmentation is seen in sea stars which accidentally break their body into fragments. Fragmentation is also observed in annelids, turbellarians and some of poriferans. Spirogyra reproduces through fragmentation during which each fragment grows into a new individual.
5) Regeneration: If the organism is cut up, its pieces can grow into separate individuals. It occurs in some fully differentiated organisms. Regeneration is also called morphallaxis. e.g. Hydra, Planaria. Regeneration is referred to tissue repair to normal state. It is restoration of normal structure and function of the organ. It is actually replacement of damaged tissue with same type of cells. Some organisms like lizards have the power of regenerating their tail.
6) Spore formation: Spore formation is one form of asexual reproduction. Spore formation is the method of developing new individuals by forming reproductive structures called spores.
7) Vegetative propagation: Vegetative propagation is one mode of asexual reproduction in plants.
Advantages of vegetative propagation
Artificial methods of vegetative propagation
Many artificial methods are developed to propagate plants vegetatively. Layering and grafting are some artificial methods of vegetative propagation.
a) Layering: This involves bending of a young stem towards the ground and burying it under the soil for development of roots . After a period of time, as the roots develop, the bent stem is cut off from the parent plant. This acts as a new plant. e.g. Jasmine.
b) Cutting: It involves planting a young cutting of the stem with buds into moist soil. This develops roots which absorb nutrition from the soil and help in the growth of new plant. e.g. Bougainvellia.
c) Grafting: It involves fusion of tissues of one plant with those of another plant. Grafting is a vegetative method of propagation for apples and roses.
8)Tissue culture: Plant tissue culture is a method used to propagate exact copies of plants under hygienic conditions. Tissue culture is the process of culturing single line cells under sterile, controlled conditions, in vitro by exposing them to nutrients, hormones and specific amount of sunlight. There are different steps involved in the tissue culture process.
Reproduction
Reproduction is the phenomenon which involves the production of an offspring by particular individual or individuals to propagate their species. Reproduction is done during reproductive phase.
Reproduction based on the number
Unicellular organisms are single celled forms whereas multicellular organisms are made up of many cells. Depending upon the complexity of the body, reproduction in unicellular organisms is different from that of multicellular organisms.
Types of reproduction
Reproduction can be of two different types, namely, asexual reproduction and sexual reproduction.
Types of asexual reproduction
Different asexual modes of reproduction by which offspring can be produced are binary fission, budding, fragmentation, regeneration, vegetative propagation, spore formation etc.
1) Binary fission: It involves the longitudinal or transverse splitting of an organism into two equal halves which develop into two separate individuals.
3) Budding: This is a form of asexual reproduction which involves development of small mass of cells as protuberances on the parental body to give rise to new structures called as buds.
4) Fragmentation: It involves breaking of parent organism into two or many fragments. Each fragment develops into an individual organism. Fragmentation is seen in sea stars which accidentally break their body into fragments. Fragmentation is also observed in annelids, turbellarians and some of poriferans. Spirogyra reproduces through fragmentation during which each fragment grows into a new individual.
5) Regeneration: If the organism is cut up, its pieces can grow into separate individuals. It occurs in some fully differentiated organisms. Regeneration is also called morphallaxis. e.g. Hydra, Planaria. Regeneration is referred to tissue repair to normal state. It is restoration of normal structure and function of the organ. It is actually replacement of damaged tissue with same type of cells. Some organisms like lizards have the power of regenerating their tail.
6) Spore formation: Spore formation is one form of asexual reproduction. Spore formation is the method of developing new individuals by forming reproductive structures called spores.
7) Vegetative propagation: Vegetative propagation is one mode of asexual reproduction in plants.
Advantages of vegetative propagation
Artificial methods of vegetative propagation
Many artificial methods are developed to propagate plants vegetatively. Layering and grafting are some artificial methods of vegetative propagation.
a) Layering: This involves bending of a young stem towards the ground and burying it under the soil for development of roots . After a period of time, as the roots develop, the bent stem is cut off from the parent plant. This acts as a new plant. e.g. Jasmine.
b) Cutting: It involves planting a young cutting of the stem with buds into moist soil. This develops roots which absorb nutrition from the soil and help in the growth of new plant. e.g. Bougainvellia.
c) Grafting: It involves fusion of tissues of one plant with those of another plant. Grafting is a vegetative method of propagation for apples and roses.
8)Tissue culture: Plant tissue culture is a method used to propagate exact copies of plants under hygienic conditions. Tissue culture is the process of culturing single line cells under sterile, controlled conditions, in vitro by exposing them to nutrients, hormones and specific amount of sunlight. There are different steps involved in the tissue culture process.