Question

Speciation of sympatric species is due to
A) Geographic isolation
B) Reproductive isolation
C) Isolation/ separation
D) Both A and C

Answer 1

Hint:It is a collection of behaviours, evolutionary mechanisms and physiological processes critical for speciation. It prevents members of two different species to mate from producing offspring.

Complete answer:
Speciation is formation of distinct and new species in the course of evolution. It involves the splitting of single evolutionary lineage into 2 or more than 2 genetically independent lineages. Sympatric speciation is an alternative to allopatric speciation in which reproductive isolation takes place without geographic isolation within a single population.
Reproductive isolation is a collection of behaviours, physiological processes and evolutionary mechanisms critical for speciation. It prevents members from mating and producing offspring. Generally, when the population is physically separated, reproductive isolation occurs.
Examples of sympatric speciation are parasitic insects that lay eggs in the fruit of wild hawthorns, apple maggot flies, bacteria, cichlids. Sympatric speciation is observed in Bacillus species because bacteria can exchange genes with the other individuals.

Additional information: There are three modes of speciation: sympatric speciation, allopatric speciation, parapatric speciation. Allopatric species occur due to geographic isolation of population species. Parapatric speciation refers to evolution of geographically adjacent populations into different species.

Thus, the correct answer is option B. i.e., Reproductive isolation.

Note:Speciation of sympatric species caused due to the reproductive isolation without any geographic isolation. There are three modes of speciation i.e. sympatric, parapatric, allopatric. Sympatric speciation is a plausible process in the multicellular eukaryotes.