Question

In the modern classification system birds are in a separate _______ from reptiles, but fossil evidence shows they have ___________.

Answer 1

Group

the same ancestry.

Common ancestry is identified in the genes. Selection forces are the drives to these physical and composition changes of an organism however, it can be traced back.

Adaptation processes occur to help species survive and thrive in the ecological balance of life. 

Answer 2

Answer:

In the modern classification system birds are in a separate class from reptiles, but fossil evidence shows they have common ancestors.

Birds refer to the group of organisms which are endothermic in nature, have feathers, beaks, four-chambered heart, high metabolic rate, lay hard-shelled eggs and lightweight skeletons.  

In biological classification, they are classified under the class Aves.

Reptiles are four-limbed organisms which come under the class Reptilia.

However, biological and fossil evidence show that birds and reptiles shared common ancestors. It is believed that birds have evolved from the reptiles. Most of the scientists believe that birds are the specialized subgroup of theropod dinosaurs.