Question

name a taxonomic or phylogenetic group that has lost a defining trait of the groups basal lineage and describe what the character is that has been lost. Describe one reason why losing a trait or a character does not "disqualify: a taxonomic group from belonging to a group that continues to exhibit a trait

Answer 1

The loss of one defining trait of the taxon or groups basal lineage comes under the study of homoplasy. Under homoplasy there is two types:

1.Parallel Homoplasy which is the presence of same traits in two species or groups due to convergent evolution and

2. Reverse Homoplasy which is the loss of a trait in a group and then reappearance of the trait in their descendants.

Because the lost trait is again reappearing in the descendants, the loss of character does not disqualify a taxonomic group from belonging to a group that continues to exhibit a trait.

An example of reverse homoplasy can be seen in limbless lizards. The limbless lizards are formed due to loss of the trait that encodes the development of the limbs in the lizard but in future generation this trait again gets activated in them and hence limbs appear.

If you have any query kindly comment before giving thumbs up. Thank you.