Modes of Reproduction
NCERT Class 10 • Science • Chapter "How do Organisms Reproduce" | NCERT Class 7 • Science • Chapter "Reproduction in Plants"
Modes of Reproduction
Reproduction is the process by which an organism produces new individuals of its own kind. It is the only life process not needed to keep an individual alive, yet without it a species ends, which is why every organism invests so heavily in it.
Asexual Reproduction
- Asexual reproduction involves a single parent and the offspring are genetically identical to it.
- Binary fission splits one cell into two, as in amoeba and bacteria; multiple fission gives many cells at once, as in plasmodium.
- Budding produces an outgrowth that detaches and grows, as in yeast and hydra.
- Fragmentation breaks the body into pieces that each grow into a new individual, as in spirogyra.
- Regeneration rebuilds a whole organism from a body part, as in planaria.
- Spore formation in fungi such as rhizopus produces many spores that spread easily and survive harsh conditions.
- Vegetative propagation uses a root, stem or leaf, as in the potato tuber, ginger rhizome, sugarcane stem and bryophyllum leaf.
- Tissue culture grows many identical plants from a few cells in the laboratory.
Sexual Reproduction in Flowering Plants
- Sexual reproduction involves two parents and produces variation, because the offspring gets genes from both.
- The stamen is the male part, consisting of anther and filament; the pistil is the female part, with stigma, style and ovary.
- A flower with both stamen and pistil is bisexual; one with only one of them is unisexual.
- Pollination is the transfer of pollen from anther to stigma, and it is self pollination within the same flower or cross pollination between flowers.
- Wind, water, insects and birds act as agents of cross pollination.
- Fertilisation is the fusion of the male gamete from the pollen tube with the egg in the ovary.
- After fertilisation the ovary becomes the fruit and the ovule becomes the seed.
| Mode | Example Organism | Parent Number |
|---|---|---|
| Binary fission | Amoeba, bacteria | One |
| Budding | Yeast, hydra | One |
| Vegetative propagation | Potato, ginger, sugarcane | One |
| Sexual reproduction | Flowering plants, animals | Two |
Pollination — the transfer of pollen grains from the anther of a flower to the stigma of the same or another flower.
Hindi me samjhein
अलैंगिक जनन में एक ही जनक होता है और संतति उसके समान होती है। लैंगिक जनन में दो जनक होते हैं, इसलिए संतति में विविधता आती है, जो विकास का आधार बनती है।
Exam me kaise aata hai
- Reproduction in amoeba occurs by — binary fission
- Reproduction in yeast occurs by — budding
- After fertilisation the ovary becomes the — fruit
- Transfer of pollen from anther to stigma is — pollination
UPSC/State PSC ke liye
- Asexual reproduction is fast and reliable but produces no variation, which makes the whole population vulnerable to one disease or change.
- Vegetative propagation is used commercially because it keeps the exact qualities of the parent plant and gives fruit far sooner than a seed grown plant.
Yahan confuse hote hain
✗ Pollination and fertilisation are the same | Pollination is transfer of pollen; fertilisation is fusion of gametes | ✓
✗ The ovule becomes the fruit | The ovule becomes the seed; the ovary becomes the fruit | ✓
✗ Asexual reproduction produces variation | It produces identical offspring | ✓
Ek nazar me
- Asexual reproduction has one parent and identical offspring.
- Fission, budding, fragmentation, regeneration, spores and vegetative propagation are its modes.
- Sexual reproduction has two parents and creates variation.
- Pollination transfers pollen; fertilisation fuses gametes; ovary becomes fruit and ovule becomes seed.