Chapter 1: Reproduction in Organisms
Short Notes
1. Lifespan ⏳
The lifespan is the period from birth to the natural death of an organism.
The lifespan of an organism is not related to its size or complexity.
Examples:
o Insects: Mayfly – 1 day
o Plants: Rice – 3-4 months; Mango – 100 years
o Animals: Crow – 15 years; Dog – 25 years; Elephant – 60-90 years; Tortoise –
100-150 years.
2. Reproduction
Reproduction is the biological process of producing new individuals of the same species.
It is essential for the continuity of species.
Two main types:
o Asexual Reproduction: Involves a single parent and produces genetically
identical offspring called clones. No gametes are involved.
o Sexual Reproduction: Involves two parents (typically) and the fusion of
gametes. The offspring show variation.
3. Asexual Reproduction
Common in: Unicellular and lower organisms.
Offspring: Genetically identical to the parent.
Methods:
o Binary Fission: The parent cell divides into two equal halves. Occurs in
organisms like Amoeba and Paramecium.
o Budding: A small bud forms on the parent, which detaches and grows into a new
individual. Seen in Hydra and Yeast.
o Zoospores: Motile (motility) microscopic spores. Found in organisms like
Chlamydomonas.
o Conidia: Non-motile spores. Found in Penicillium.
o Vegetative Propagation (in plants):
Short Notes
1. Lifespan ⏳
The lifespan is the period from birth to the natural death of an organism.
The lifespan of an organism is not related to its size or complexity.
Examples:
o Insects: Mayfly – 1 day
o Plants: Rice – 3-4 months; Mango – 100 years
o Animals: Crow – 15 years; Dog – 25 years; Elephant – 60-90 years; Tortoise –
100-150 years.
2. Reproduction
Reproduction is the biological process of producing new individuals of the same species.
It is essential for the continuity of species.
Two main types:
o Asexual Reproduction: Involves a single parent and produces genetically
identical offspring called clones. No gametes are involved.
o Sexual Reproduction: Involves two parents (typically) and the fusion of
gametes. The offspring show variation.
3. Asexual Reproduction
Common in: Unicellular and lower organisms.
Offspring: Genetically identical to the parent.
Methods:
o Binary Fission: The parent cell divides into two equal halves. Occurs in
organisms like Amoeba and Paramecium.
o Budding: A small bud forms on the parent, which detaches and grows into a new
individual. Seen in Hydra and Yeast.
o Zoospores: Motile (motility) microscopic spores. Found in organisms like
Chlamydomonas.
o Conidia: Non-motile spores. Found in Penicillium.
o Vegetative Propagation (in plants):
