Chapter 7: How Do Organisms Reproduce?

When a single cell divides into two equal halves, it is known as binary fission. Bacteria and amoeba are examples of binary fission.

When a single cell divides into multiple daughter cells at the same time, it is known as multiple fission. Algae and sporozoans are examples of multiple fission.

Following are the ways through which an organism will be benefited if it reproduces through spores:

• Number of spores produced in one sporangium would be large.
• In order to avoid competition at one place, spores can be distributed to faraway places with the help of air.
• In order to prevent dehydration under unfavorable conditions, the spores are covered by thick walls.

Organisms at higher complex levels cannot give rise to new individuals through regeneration because they have organization of their organs system at different levels. All these organ systems are interconnected and work in full coordination. They can regenerate a few of their lost body parts like skin, blood, muscles, etc. but can’t give rise to new individuals.

Following are the advantages of practising vegetative propagation for growing some types of plants:

• Crops like orange, banana, pineapple do not have viable seeds, so vegetative propagation can be used.
• It is a rapid, cheap and easier method to grow crops.
• It can be used in places where seed germination fails.
• A good quality of variety can be preserved.

DNA copying is an essential part of the process of reproduction because it carries the genetic information from the parents to offspring. A copy of DNA is produced through some chemical reactions resulting in two copies of DNA. Along with the additional cellular structure, DNA copying also takes place, which is then followed by cell division into two cells.