Chapter 20, Problem 1MCQ

Summary Introduction

Introduction:

Biodiversity describes the variety and richness of life on earth. Variability can be observed among living organisms in terrestrial, marine, and other aquatic ecosystems. The three levels of biodiversity are genetic, species, and ecosystem.

Answer to Problem 1MCQ

Correct answer:

Natural disasters, such as earthquakes are not the main cause of today’s biodiversity crisis. Hence, the correct answer is option a.

Explanation of Solution

Reason for correct answer:

Option a. is given as “Natural disasters, such as earthquakes.”

The main causes of biodiversity loss are habitat destruction and degradation, invasive species, human population size, overexploitation, and pollution. Earthquakes may not be considered as the main cause for the loss of biodiversity. However, they may hamper the biodiversity present in the ground water.

Reason for incorrect answer:

Option b. is given as, “Habitat destruction and degradation.”

The prairies, wetlands, and forests are replaced with farms and cities. Deforestation destroys the habitat of several species of plants and animals. The freshwater habitats are destroyed due to the construction of dams and levees. The destruction of habitat is the primary threat to diversity. Hence, option b. is incorrect.

Option c. is given as, “Overexploitation.”

Overexploitation occurs when the harvesting of species from the wild occurs at faster rates than they can recover. It occurs due to overhunting of terrestrial animals. Overexploitation results in the extinction of species. Hence, option c. is incorrect.

Option d. is given as, “Introduction of nonnative species.”

An introduced species is a species that is introduced by humans either intentionally or accidently. A nonnative species that become invasive causes immense destruction. The invasive species may harm the environment, economy, or human health. They may change the composition of a community and may spread diseases to native species. Hence, option d. is incorrect.

Hence, the options b., c., and d. are incorrect.

Conclusion

Thus, the biodiversity crisis in the present scenario is not caused by natural disasters such as earthquakes. The correct option is a.