Question

Which one of the following is a characteristic of a biological community?
A. Natality
B. Mortality
C. Sex ratio
D. Stratification

Answer 1

Hint: In biology, the biological community refers to the community that involves an interacting group of various species in a common location. One of the examples of a biological community is the forest of trees and the plants that are inhabited by animals and soil containing bacteria and fungi.

Complete answer: One of the characteristic features of a biological community is stratification. The phenomenon of having one or more than one stratum formed by different plants or organisms in the same place is called stratification. It can occur both vertical and horizontal. It occurs due to succession as a result of which species become adapted to their habitat. The vertical stratification can be seen in forests that result from the varying degrees of light that the different strata receive.
a) The overall structure of the biological community is determined by the number of species within it, the interactions among the species, the number of each species found within it, and the ability of the community to return to normal after a disruptive influence such as drought or fire. The scientific term for birth rate in population ecology is natality. It refers to the crude birth rate in a period which is defined as the total number of live births per thousand population divided by the length of the period in years. Natality is not a characteristic of the biological community.
b) Mortality rate is also called the death rate. It can be defined as the measure of the number of deaths which occur in a particular area which is scaled to the size of that area by per unit time. The unit of mortality rate is expressed as deaths per 1,000 individuals per year. It is not a characteristic of the biological community.
c) Sex ratio can be defined as a ratio of males to females in a population.
Therefore, option D is the correct answer.

Note: As stratification can accommodate a large number of organisms of different types. The animals that occupy such ecological niches although geographically separated are called ecological equivalents.