Q.Give an account on the major causes for the extinction of a particular species on earth.

Step 1. Extinction is described as common, and arguably inevitable, whenever a species cannot adapt to large or rapid environmental change — this inability to keep pace with change is the root cause underlying every specific trigger.

Step 2. At the level of a single species, extinction can be caused by a purely environmental event, such as a flood, that eliminates the species' habitat or population directly.

Step 3. It can also be caused by a biological event, such as a disease outbreak, or the loss of half or more of the species' available food resource, undermining its ability to survive and reproduce.

Step 4. At a larger scale, mass and global extinctions can be driven by more catastrophic events — volcanic eruptions eliminating half or more of species across a whole region or ecosystem (mass extinction), or planet-wide events such as a 'Snowball Earth' glaciation or a sharp rise in atmospheric CO2 levels (global extinction). …

Distinguish environmental-event causes from biological-event causes, and connect both back to the chapter's …

• Listing only human-driven causes (which this TN NCERT-era chapter does not emphasise) instead of the natural environmental/biological causes actually given. …