Question

Archaeopteryx is a connecting link between reptiles and birds. Justify the statement by giving two characteristics of each group.

Answer 1

Hint: Despite the presence of numerous avian features, Archaeopteryx had many non-avian tetrapod dinosaur characteristics. So, it is a connecting link between reptiles and birds.

Complete answer:
Reptilian characters of archaeopteryx: -
- The body axis is more or less lizard-like
- A long tail is present.
- The bone is pneumatic(hollow)
- The jaws of archaeopteryx have similar teeth as that of reptiles
- They have weak sternum like that of reptiles
- Presence of free caudal vertebrae as found in lizards
- The hand bears a typical reptilian plan and each finger terminates in a claw.

Bird characters of archaeopteryx: -
- Presence of feathers on the body
- The two limbs are modified into a beak
- The forelimbs are modified into wings
- The hind-limbs are built on the typical avian plan.
- An intimate fusion of skull bones as seen in the birds.

Note: Archaeopteryx (Arche- primitive, apteryx – wing).
Archaeopteryx was found in rocks of the cretaceous period. Archaeopteryx lithography was discovered in 1861 by Andreas Wagner from the lithographic quarry at splendored Bavaria, in Germany. This fossil is placed in the British Museum, London. It displays characters of both reptiles and birds.
The fossil organisms which show characters of two different groups are called Missing links. The most common example being Archaeopteryx.