Question

Which one of the following is a characteristic feature of the cropland ecosystem?

• A. Ecological succession
• B. Absence of soil organisms
• C. Least genetic diversity
• D. Absence of weeds

Answer 1

The correct option is C Least genetic diversity

Introduction to cropland ecosystem
A cropland ecosystem refers to an artificial ecosystem created by man, in which crops like wheat, maize, etc. are grown.

Absence of weeds
Croplands are usually infested with unwanted weeds which compete with the crops for resources. Thus option A is incorrect.

Ecological succession
Ecological succession is a steady and gradual change in the composition and structure of biotic communities in an area with a changing environment. It is predictable, sequential, and in accordance with the changing physical environment.
In man-made ecosystems like the cropland, ecological succession is not observed as specific crops are grown for a season and then harvested, after which new crops are sown again. Thus, there is no gradual change seen in the composition or structure of the communities in the cropland.
Thus, option B is incorrect.

Absence of soil organisms
Soil organisms are integral parts of cropland ecosystems as they contribute to increasing soil fertility. Thus, option C is incorrect.

Least genetic diversity
1) Genetic diversity refers to the total of genetic variations found in a species.
2) A characteristic feature of cropland ecosystems is the minimum or least genetic diversity.
3) This is because the same type of crop is grown in this ecosystem and hence exhibits minimum diversity.
Thus, option D is correct.

Final answer
(D) Least genetic diversity