Which of the following statements about classification is not true?
I. Members of a family are less similar than members of an included genus II. An order has more members than the number of members in an included genus Ill. Families have more members than phyla IV. Members of a family share a common ancestor in the more distant past than members of an included genus V. The number of species in a taxon depends on their relative degree of similarity:

Options

A. Only III
B. Only IV
C. Only V
D. None

Answer

To determine which statement about classification is not true, we will analyze each statement one by one based on our understanding of taxonomic hierarchy.

1. **Statement I**: "Members of a family are less similar than members of an included genus."
- In taxonomic classification, a genus is a more specific category than a family. Therefore, members of a genus are indeed more similar to each other than members of a family. This statement is **true**.

2. **Statement II**: "An order has more members than the number of members in an included genus."
- An order is a broader classification than a genus, which means it can include multiple genera. Thus, it is correct to say that an order has more members than an included genus. This statement is **true**.

3. **Statement III**: "Families have more members than phyla."
- This statement is incorrect. A phylum is a higher taxonomic rank than a family, meaning that a phylum encompasses multiple families. Therefore, phyla have more members than families. This statement is **not true**.

4. **Statement IV**: "Members of a family share a common ancestor in the more distant past than members of an included genus."
- Since a genus is a subset of a family, members of a family do share a common ancestor that is more distant than that of members of a genus. This statement is **true**.

5. **Statement V**: "The number of species in a taxon depends on their relative degree of similarity."
- The classification of species into taxa is based on their similarities and differences. Therefore, this statement is also **true**.

Based on this analysis, the statement that is not true is **Statement III**: "Families have more members than phyla."