Class 10 | Science 2 | Chapter 3 | Easy notes Life Processes in Living Organisms Part - 2

Class 10 | Easy notes on chapter 3 Life Processes in Living Organisms Part - 2

Asexual reproduction of unicellular organisms :

There are five methods of asexual reproduction in multicellular organisms.

1. Fragmentation 

2. Regeneration 

3. Budding 

4. Vegetative propagation 

5. Spore formation

1. Fragmentation :

• This type of reproduction occurs in algae like Spirogyra, and sponges like Sycon.

• Whenever there is plenty of water and nutrients are

available to Spirogyra, its filaments grow up very fast and

break up into many small fragments.

• Each fragment starts to live independently.

• If the body of Sycon breaks up accidentally into many fragments, each fragment develops into new Sycon.

2. Regeneration :

• limited regeneration :

eg. Wall lizard

The wall lizard breaks up and discards some part of its tail in emergency. Discarded part is regenerated after a period.

• Complete regeneration :

eg. Planaria

Planaria breaks up its body into two parts and thereafter each part regenerates remaining part of the body and thus two new Planaria are formed. 

3. Budding :

• Budding occurs in Hydra .

• Under favorable conditions,

at specific part of its body, an outgrowth (bud) is formed

by repeated divisions of regenerative cells of body wall.

• Bud grows up progressively and finally forms a small hydra. 

• Parent hydra supplies nutrition to the budding hydra.

• Budding hydra separates from

parent hydra and starts to lead an independent life when it grows up and becomes able to lead an independent life.

4. Vegetative Propagation : 

Reproduction in plants with the help of vegetative parts like root, stem, leaf & bud is called as vegetative reproduction.

examples, 

1. potatoes - Propagation in potatoes is preformed with the help of ‘eyes’ present on tuber.

2. Bryophyllum - it is performed with the help of buds present on leaf margin.

3. sugarcane & grasses-vegetative propagation occurs with the help of buds present on nodes.

4. carrot and radish perform vegetative propagation with the help of roots.

5. Spore formation :

• Fungi like Mucor have filamantous body.

• They have sporangia. Spores are formed in this sporangia. 

• Once the spores are formed,

sporangia burst and spores are released.

• Spores germinate in moist and warm place and new

fungal colony is formed.