Chapter 5, Problem 2STP

Summary Introduction

Introduction:

The removal or termination of an organism or a group of organisms is termed as extinction. The extinction actually occurs when the last individual of the species die and there is no further chance of reproduction of more organisms of this species.

Answer to Problem 2STP

Correct option is, option (A) background extinction.

Explanation of Solution

Explanation for correct options:

(A) Background extinction. It is the extinction of species due to natural causes, climate change, habitat destruction, and competition between two species for same resources. In this case the number of extinct species remains constant for many years. Therefore, graph labelled “1” depicts background extinction. Hence, option (A) is correct.

Explanation for incorrect options:

(B) Habitat destruction. It is the event when a habitat becomes incapable of supporting the species, leading to their extinction. Habitat destruction is a part of background extinction. Hence, option (B) is incorrect.

(C) Mass extinction. It is the rapid decrease in biodiversity on the earth. This result in sharp extinction of many species from the earth in sometime. During mass extinction, the graph of extinction is steep for years. Hence, option (C) is incorrect

(D) Species overexploitation. This means using or exploiting wildlife species at the rate, at which the nature cannot revive itself. In other words, it means exploiting species at much higher rate than their reproduction rate. This leads to extinction of that sepcies, within a span of time. Hence, option (D) is incorrect