Give reason – ‘Archaeopteryx is called connecting link between reptiles and birds’.
Organisms showing characters of two groups (kingdoms, phyla, classes, etc.) are called connecting links between the two groups.
Archaeopteryx shows characters of birds as well as of reptiles.
Avian characters of Archaeopteryx:
a. It has skull bones completely fused: cranium rounded with large orbits and a single condyle.
b. Jaws modified into beak.
c. Forelimbs modified into wings.
d. Limb bones have their first toe opposable.
e. Foot with clawed digits.
f. Feathery exoskeleton
Reptilian characters of Archaeopteryx:
a. Jaw with homodont teeth.
b. Ribs with single head.
c. Abdominal ribs somewhat like those seen in crocodiles.
d. Forelimbs modified into wings and three digits ending in distinct claws.
e. The hind limb had four digits ending with claws.
f. Long tail.
Thus, Archaeopteryx is called connecting link between reptiles and birds.