⏳🐦🦴

#archaeopteryx #ancient bird #prehistoric bird #fossil bird #bird ancestor #urvogel #fossil evidence #mesozoic bird

🔑🦴🦖🐦

#synapomorphy #derived trait #homology #fossil evidence #key characteristic #birds are dinosaurs #evolutionary link

🐒👣🦴

#laetoli footprints #hominin tracks #fossil evidence #ape ancestor #bipedal evidence #ancient footprints