Question

Sibling species can be distinguished on the basis of
A. Morphospecies concept
B. Biospecies concept
C. Evolutionary species concept
D. Keystone species concept

Answer 1

Species are groups of organisms and are the basic unit of biological classification. Species are a group of organisms that can interbreed within themselves and can produce fertile offspring. The characteristics of the species are derived from a common ancestry. The definition of a species which involves a set of questions is called species concept.

Complete answer:
Species is a group of closely related organisms which are able to produce fertile offspring after mating and reproduction. The species are formed from a common ancestral population but due to several evolutionary processes are divided into many species forming a species complex. A species complex is a group of closely related organisms that are similar in appearance and the differentiation between them are often unclear. These types of species may be known as sibling species.

A sibling species is defined as the group of organisms that can be differentiated only after genetic analysis. The sibling species appears similar in appearance but they cannot interbreed with each other. The sibling species are reproductively isolated. The sibling species further evolve into morphologically and taxonomically different species as they do not mate with one another. As a result of which two types of species are formed. The sibling species can be only distinguished on the basis of the genetics that is evolved.

Option B: The biological species concept was proposed by Mayr and he defined species as a group of organisms that are potentially interbreeding populations which are reproductively isolated from other such species. Biospecies are groups of organisms that do not interbreed with each other even when sharing the common environment and can be separated through genetic differences.

Option A: The morphospecies concept is one of the oldest species concepts proposed by Linnaeus. According to this concept the differences in the morphological characteristics that are used to distinguish the species. However, this does not take into account variation as a potential condition for speciation.

Option C: Evolutionary species concept explains the formation of a species as in a single lineage ancestor descendent organism which are maintained as separate species from other such species. In this concept, each species has a chance to evolve separately. This concept was proposed by Wiley and developed by Simpson.

Option D: Keystone species concept was developed by R.T. Paine and it defines a keystone species as a species that has a large effect on its natural environment on the basis of its abundance. These species act as important and critical species that help to maintain the ecological community.

Hence, the correct answer is option (B).

Note: Sibling species are related groups of organisms that are morphologically similar but they cannot interbreed with other such species. The sibling species are reproductively isolated and evolve as separate groups of species. The Biospecies concept explains species as potentially interbreeding organisms but they are not able to reproduce. Thus, the Biospecies concept helps to distinguish the sibling species.