2026 FULL SOLUTION QUESTIONS AND
ANSWERS GRADED A+
●● how fossils are dated.
Answer: based on stratigraphy (studying how deeply a fossil is buried in
the rock strata) and radioisotope dating
●● reasons for the lack of bird fossils.
Answer: many eaten
small bones didn't survive
only ones we have are from volcanic stone or sandstone where bird
gently covered by silt or ash until fossilized
most found are aquatic birds (loons, gulls, petrels, cranes, etc)
●● Archaeopteryx.
Answer: first fossil animal with feathers
discovered in Barvaria in 1861
had reptilian teeth
tail heavy
couldn't fly
most basal bird in avian lineage
, ●● the fact that cladistics are not static, relationships change as new
fossils are found.
Answer: they change as fossils of new species are found and their
morphology info is entered into data sets
-individual cladograms can vary, depending on the morphology data
utilized to make them; up to scientists' judgement
●● characteristics of theropod dinosaurs.
Answer: bipedal
carnivorous
many had feathers
laid eggs in nest
●● ornithurines give rise to modern birds arising in the last 5 million
years.
Answer: had superior flight capability than basal avian species because
of several anatomical changes. elongated coracoid bones and
strengthened rib cage to provide skeletal strength for physical stress of
flight and large keeled sternum to support flight muscles
●● anatomical differences between prehistoric birds and the birds of
today.