82. Which one of the following statements is NOT TRUE about homologous characters?
    (1) Similar traits may not be homologous
    (2) Similar traits may be a result of convergent evolution
    (3) A homologous trait that is derived and shared from a common ancestor is called an
    autapomorphy
    (4) Homologous characters may show structural similarity but functional diversity

Homologous characters are fundamental to understanding evolutionary relationships. These are traits shared by different species due to inheritance from a common ancestor, often displaying structural similarity but potentially serving different functions. However, not all statements about homologous characters are accurate. Let’s clarify which statement is NOT true regarding homologous characters and why.

Examining the Statements

1. Similar traits may not be homologous
   This is true. Not all similar traits are homologous; some may be analogous, arising independently due to convergent evolution rather than shared ancestry.

2. Similar traits may be a result of convergent evolution
   This is true. Convergent evolution produces analogous traits—similar in function but not derived from a common ancestor.

3. A homologous trait that is derived and shared from a common ancestor is called an autapomorphy
   This is NOT true. An autapomorphy is a derived trait unique to a single lineage or taxon, not shared among multiple groups. In contrast, a synapomorphy is a derived trait shared by two or more groups and inherited from their most recent common ancestor. Homologous traits shared by multiple taxa are synapomorphies, not autapomorphies.

4. Homologous characters may show structural similarity but functional diversity
   This is true. Homologous structures often have similar anatomy due to common ancestry but can serve different functions in different species (e.g., the forelimbs of humans, whales, and bats).

Why Is Statement 3 Incorrect?

• Autapomorphy refers to a unique, derived trait found only in a single lineage, not a trait shared by multiple taxa due to common ancestry.

• Homologous traits that are shared and derived are called synapomorphies, not autapomorphies.

Conclusion

The statement that is NOT true about homologous characters is:

(3) A homologous trait that is derived and shared from a common ancestor is called an autapomorphy.