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Multiple Choice
Based on cladistics, which eukaryotic kingdom is considered polyphyletic and, therefore, unacceptable in modern classification systems?
A
Plantae
B
Animalia
C
Protista
D
Fungi
Verified step by step guidance
1
Understand the concept of cladistics: Cladistics is a method of classification based on common ancestry and evolutionary relationships. It groups organisms into clades, which include an ancestor and all its descendants.
Define the term 'polyphyletic': A polyphyletic group is one that includes organisms from different evolutionary lineages, meaning they do not share a recent common ancestor. Such groups are not considered valid in modern classification systems.
Analyze the eukaryotic kingdoms: Plantae, Animalia, and Fungi are monophyletic groups, meaning they include all descendants of a common ancestor. Protista, however, is a polyphyletic group because it includes a diverse range of organisms (e.g., algae, protozoa) that do not share a single common ancestor.
Understand why Protista is considered unacceptable: Modern classification systems aim to reflect evolutionary relationships. Since Protista is polyphyletic, it does not accurately represent a single evolutionary lineage and is therefore not used in cladistics-based classification.
Conclude that Protista is the correct answer: Based on the principles of cladistics and the definition of polyphyletic groups, Protista is the eukaryotic kingdom considered polyphyletic and unacceptable in modern classification systems.