- Reproduction is a process in which an organism produces young ones (offspring) similar to itself.
- The period from birth to the natural death of an organism is known as its lifespan.
- No individual is immortal, except unicellular organisms. There is no natural death in unicellular organisms.
Organism Lifespan Organism Lifespan Organism Lifespan
Rose 5-7 years Butterfly 1-2 weeks Tortoise 100-150 yrs
Life spans Rice plant 3-7 months Fruit fly 2 weeks Crow 15 yrs
of some Banyan tree 400+ yrs Parrot 140 yrs Cow 22 yrs
organisms Banana tree 2-3 yrs Crocodile 60 yrs Elephant 50-70 yrs
Dog 22 yrs Horse 40-50 yrs
- Based on the number of participants, reproduction is 2 types: Asexual reproduction & Sexual reproduction.
ASEXUAL REPRODUCTION
- It is the production of offspring by a single parent. Examples for vegetative propagules:
- It is seen in unicellular organisms, simple plants & animals. Buds (‘eyes’) of the potato tuber.
- The offspring are identical to one another and to their Rhizomes of banana & ginger.
parent. Such morphologically and genetically similar Buds & Rhizomes arise from the nodes of modified stems.
individuals are known as clone. The nodes come in contact with damp soil or water and
Types of asexual reproduction produce roots and new plants.
Adventitious buds of Bryophyllum. They arise from the
a. Fission: In this, the parent cell divides (cell division) into
notches at margins of leaves.
two or more individuals. E.g. Protists and Monerans.
Bulbil of Agave.
Fission is 2 types:
Offset of water hyacinth.
Binary fission: It is the division of parent cell into two
Runner, sucker, tuber, bulb etc.
individuals. E.g., Amoeba, Paramecium.
Multiple fission: It is the division of parent cell into
many individuals. E.g. Plasmodium, Amoeba.
Under unfavourable condition, Amoeba withdraws its
pseudopodia and secretes a 3-layered hard covering (cyst)
around itself. It is called encystation. Under favourable
conditions, encysted Amoeba undergoes multiple fission
to give many minute amoeba or pseudopodiospores. The
cyst wall bursts out and spores are liberated to grow up
into many amoebae. This is called sporulation.
b. Budding: In this, a bud appears and grows in the parent
body. After maturation, it is detached from parent body to Other asexual reproductive structures: E.g. zoospores
form new individual. E.g. Hydra, Sponge, Yeast etc. (microscopic motile structures in some algae and protists),
conidia (Penicillium) and gemmules (sponge).
c. Fragmentation: In this, the body breaks into distinct
pieces (fragments) and each fragment grows into an adult Asexual reproduction is the common method in simple
capable of producing offspring. E.g. Hydra. organisms like algae and fungi. During adverse conditions,
d. Vegetative propagation: It is the production of offspring they can shift to sexual method.
from vegetative propagules in plants. Higher plants reproduce asexually (vegetative) & sexually.
Vegetative propagules are units of vegetative propagation. But most of the animals show only sexual reproduction.
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- The period from birth to the natural death of an organism is known as its lifespan.
- No individual is immortal, except unicellular organisms. There is no natural death in unicellular organisms.
Organism Lifespan Organism Lifespan Organism Lifespan
Rose 5-7 years Butterfly 1-2 weeks Tortoise 100-150 yrs
Life spans Rice plant 3-7 months Fruit fly 2 weeks Crow 15 yrs
of some Banyan tree 400+ yrs Parrot 140 yrs Cow 22 yrs
organisms Banana tree 2-3 yrs Crocodile 60 yrs Elephant 50-70 yrs
Dog 22 yrs Horse 40-50 yrs
- Based on the number of participants, reproduction is 2 types: Asexual reproduction & Sexual reproduction.
ASEXUAL REPRODUCTION
- It is the production of offspring by a single parent. Examples for vegetative propagules:
- It is seen in unicellular organisms, simple plants & animals. Buds (‘eyes’) of the potato tuber.
- The offspring are identical to one another and to their Rhizomes of banana & ginger.
parent. Such morphologically and genetically similar Buds & Rhizomes arise from the nodes of modified stems.
individuals are known as clone. The nodes come in contact with damp soil or water and
Types of asexual reproduction produce roots and new plants.
Adventitious buds of Bryophyllum. They arise from the
a. Fission: In this, the parent cell divides (cell division) into
notches at margins of leaves.
two or more individuals. E.g. Protists and Monerans.
Bulbil of Agave.
Fission is 2 types:
Offset of water hyacinth.
Binary fission: It is the division of parent cell into two
Runner, sucker, tuber, bulb etc.
individuals. E.g., Amoeba, Paramecium.
Multiple fission: It is the division of parent cell into
many individuals. E.g. Plasmodium, Amoeba.
Under unfavourable condition, Amoeba withdraws its
pseudopodia and secretes a 3-layered hard covering (cyst)
around itself. It is called encystation. Under favourable
conditions, encysted Amoeba undergoes multiple fission
to give many minute amoeba or pseudopodiospores. The
cyst wall bursts out and spores are liberated to grow up
into many amoebae. This is called sporulation.
b. Budding: In this, a bud appears and grows in the parent
body. After maturation, it is detached from parent body to Other asexual reproductive structures: E.g. zoospores
form new individual. E.g. Hydra, Sponge, Yeast etc. (microscopic motile structures in some algae and protists),
conidia (Penicillium) and gemmules (sponge).
c. Fragmentation: In this, the body breaks into distinct
pieces (fragments) and each fragment grows into an adult Asexual reproduction is the common method in simple
capable of producing offspring. E.g. Hydra. organisms like algae and fungi. During adverse conditions,
d. Vegetative propagation: It is the production of offspring they can shift to sexual method.
from vegetative propagules in plants. Higher plants reproduce asexually (vegetative) & sexually.
Vegetative propagules are units of vegetative propagation. But most of the animals show only sexual reproduction.
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