Characteristics shared by members of a clade and only by members of that clade are called:

• A. Synapomorphies
• B. Homoplasies
• C. Autapomorphies
• D. Analogies

Answer: (A)

Verified step by step guidance

1. Understand the key terms in the question: A 'clade' is a group of organisms that includes a common ancestor and all its descendants. The question is asking about characteristics shared exclusively by members of a clade.
2. Define the term 'synapomorphies': These are shared derived traits that are present in an ancestor and all its descendants, and they are unique to that clade. This makes them a defining feature of the clade.
3. Differentiate between the other terms: 'Homoplasies' refer to traits that arise independently in different lineages due to convergent evolution, not shared ancestry. 'Autapomorphies' are traits unique to a single species or lineage within a clade, not shared by the entire clade. 'Analogies' are traits that are similar due to function but not due to shared ancestry.
4. Focus on the exclusivity of the trait: The question specifies that the characteristic is shared by members of the clade and only by members of that clade. This exclusivity is a hallmark of synapomorphies.
5. Conclude that the correct answer is 'Synapomorphies' because they are the shared derived traits that define a clade and are unique to its members.