Question

What is true regarding background extinction?

• A. Calculated from widespread events that wipes out the majority of living plants and animals.
• B. The extinction of individual species due to natural environmental or ecological factors.
• C. Calculated from rate of extinction that occurred before homo sapiens appeared on Earth.
• D. Species going extinct once every thousand years.

Answer 1

Answer: (B), (C)

Calculated from rate of extinction that occurred before homo sapiens appeared on Earth.

Background extinction refers to the standard rate of extinction in Earth's geological and biological history before humans became a primary contributor to extinctions. Background extinctions happen due to natural and ecological factors. On the other hand, mass extinction is a widespread event that wipes out the majority of living plants and animals. A mass extinction is a relatively sudden (like glaciation) process, leading to global decrease in the diversity of life forms. Five mass extinctions have occurred before humans evolved and they were due to natural disasters. Species went extinct even before humans evolved on Earth. However, human activity has amplified the background extinction rate tremendously.