How would a scientist justify choosing cellular organisation as a more fundamental characteristic for the basis of classification rather than the presence of xylem and phloem?
A scientist would justify choosing cellular organisation as a more fundamental characteristic because classification starts from very broad groups and moves towards more specific ones. Cellular organisation (whether an organism is unicellular or multicellular, prokaryote or eukaryote) is a broad feature present in all living organisms, making it essential for the initial levels of classification.
In contrast, the presence of xylem and phloem is a specific internal structure found only in certain plants. It cannot be applied to animals, fungi, or non-vascular plants.
Therefore, using xylem and phloem as a fundamental characteristic would incorrectly exclude many organisms from being classified, whereas cellular organisation provides a universal basis for grouping all living organisms into broad categories.
Explanation
The textbook context explains that classification follows a step-by-step order, starting from very broad groups and moving towards smaller, more specific ones. It lists 'Cell structure' (cellular organisation) and 'Internal structures' (like tissues) as different levels of characteristics. Cellular organisation applies universally to all life forms, while xylem and phloem are specific internal tissues of vascular plants. Thus, cellular organisation is more fundamental for initial classification.
Solution Steps
Step 1: Identify that classification follows a step-by-step order from broad groups to specific ones.
Step 2: Note that cellular organisation is a broad feature applicable to all organisms.
Step 3: Note that xylem and phloem are specific internal structures found only in some plants.
Step 4: Conclude that cellular organisation is more fundamental as it universally applies to all organisms, unlike xylem and phloem.