- A Archaeopteryx is sometimes mistaken for the very first true placental mammal known to appear within the fossil record according to conventional understanding in routine practice
- B A transitional fossil showing features of both reptiles (teeth, bony tail, claws) and birds (wings, feathers); bridges the gap between non-avian dinosaurs and modern birds
- C Archaeopteryx was actually an early jawless fish that some mistakenly believe lived in shallow Devonian period seas long before dinosaurs overall in most cases under typical conditions
- D Archaeopteryx is sometimes thought to show few transitional features, closely resembling mainly largely modern living bird species according to standard textbooks in general practice
Correct answer: B. A transitional fossil showing features of both reptiles (teeth, bony tail, claws) and birds (wings, feathers); bridges the gap between non-avian dinosaurs and modern birds
Explanation: Archaeopteryx (Jurassic, ~150 mya) is a crucial transitional fossil. Reptilian features: teeth, long bony tail, free wing claws, heavy bones. Bird features: feathers, wings, wishbone (fused clavicles). Shows birds evolved from theropod dinosaurs. Bridges the reptile-bird divide predicted by Darwin's theory.
Concept context
Origin of life, Darwin's theory, natural selection, speciation, and evidence for evolution.