The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed 3-chambered hearts. Birds and mammals, however, are alike in having 4-chambered hearts. The 4 chambered hearts of birds and mammals are best described as homoplasies.
<h3>What about homoplasies?</h3>
It is more frequently a modified version of an inherited characteristic.
For instance, the scales that were already present in its reptilian parent led to the evolution of feathers in birds.
Similar to reptiles, mammals developed fur from their predecessors' scales.
The same set of data can typically yield more than one potential cladogram.
Different species of legged lizards developed into snakes and lizards with limbless bodies.
Natural selection does not affect a sizable number of mutations.
They came to the conclusion that reptiles, birds, and mammals all descended from the same ancient reptilian progenitor.
