Modern Classification Systems — NEET Biology

Correct answer: D — S1, S2 and S5 only

Let's evaluate each statement based on the NCERT text: S1: "Such systems were artificial; they separated the closely related species since they were based on a few characteristics." This statement is correct. S2: "natural classification systems developed, which were based on natural affinities among the organisms and consider, not only the external features, but also internal features, like ultra-structure, anatomy, embryology and phytochemistry." This statement is correct. S3: "At present phylogenetic classification systems based on evolutionary relationships between the various organisms are acceptable. This assumes that organisms belonging to the same taxa have a common ancestor." The statement says organisms have 'different' ancestors, which is incorrect. They assume a 'common' ancestor. S4: "Numerical Taxonomy... is based on all observable characteristics. Number and codes are assigned to all the characters and the data are then processed. In this way each character is given equal importance and at the same time hundreds of characters can be considered." The statement says it processes data without giving equal importance to each character, which is incorrect. S5: "Cytotaxonomy, that is based on cytological information like chromosome number, structure, behaviour and chemotaxonomy, that uses the chemical constituents of the plant to resolve confusions, are also used by taxonomists these days." This statement is correct. Therefore, statements S1, S2, and S5 are correct. Option D includes S1, S2, and S5, which are all correct statements. Option B incorrectly includes S3 and S4. Option C incorrectly includes S4. Option A incorrectly includes S3. The core concept tested is the understanding of different classification systems and their distinguishing characteristics as described in NCERT.