History of Biological Classification

Which mnemonic represents the correct order of Linnaean taxonomic ranks?
A. "King Philip Came Over For Good Soup"
B. "Dear King Philip Cooked Our Favorite Meal"
C. "Keep Pond Clean Or Frogs Get Sick"
D. "Big Cats Often Fear Giant Snakes"

Answer: A (Key: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.)

What was the primary basis of Linnaeus’s original two-kingdom system?
A. DNA sequencing
B. Cellular structure (prokaryotic vs. eukaryotic)
C. Morphological similarities (plants vs. animals)
D. Reproductive strategies

Answer: C (Key: Linnaeus classified organisms as plants (photosynthetic) or animals (mobile, heterotrophic).)

Why was the Kingdom Protista added in the three-kingdom system?
A. To include prokaryotic bacteria
B. To accommodate unicellular eukaryotes (e.g., algae, protozoans)
C. To separate fungi from plants
D. To classify viruses

Answer: B (Key: Protista grouped eukaryotes that didn’t fit as plants or animals.)

Which kingdom was introduced to classify bacteria and blue-green algae?
A. Fungi
B. Monera
C. Archaea
D. Protista

Answer: B (Key: Monera included prokaryotes like bacteria.)

What distinguishes homology from analogy in phylogenetics?
A. Homology results from convergent evolution; analogy reflects shared ancestry.
B. Homology reflects shared ancestry; analogy results from convergent evolution.
C. Both terms describe DNA sequence similarities.
D. Homology applies only to plants; analogy applies to animals.

Answer: B (Key: Homology = common ancestry; analogy = similar functions but different origins, like bird vs. bat wings.)

Which taxonomic rank is most specific?
A. Class
B. Order
C. Genus
D. Species

Answer: D (Key: Species is the narrowest rank, e.g., Homo sapiens.)

What does a "rooted" phylogenetic tree show?
A. The exact time of species divergence
B. The common ancestor of all depicted taxa
C. Only extinct species
D. Environmental influences on evolution

Answer: B (Key: The root represents the last common ancestor.)

Which pair of organisms would share the most derived characters?
A. Two species in the same family
B. Two species in different domains
C. Two species in the same order but different classes
D. Two species in the same genus

Answer: D (Key: Closely related species (same genus) share more recent adaptations.)

Why did the five-kingdom system separate fungi from plants?
A. Fungi are prokaryotic.
B. Fungi are heterotrophic (non-photosynthetic).
C. Fungi lack cell walls.
D. Fungi are unicellular.

Answer: B (Key: Fungi absorb nutrients, unlike photosynthetic plants.)

What is the purpose of molecular systematics?
A. To classify organisms by color
B. To infer evolutionary relationships using DNA
C. To study extinct species only
D. To replace Linnaean taxonomy

Answer: B (Key: Molecular data (e.g., DNA) reveal deeper evolutionary links.)