Which of the following is constructed by nesting clades characterized by shared derived characters?

• A. A linkage map
• B. A karyotype
• C. A cladogram
• D. A Punnett square

Answer: (C)

Verified step by step guidance

1. Understand the key terms in the question: a 'clade' is a group of organisms that includes an ancestor and all its descendants, and 'shared derived characters' are traits that are present in an organism and its descendants but not in more distant ancestors.
2. Recognize that a 'cladogram' is a diagram used in phylogenetics that shows relationships among organisms based on shared derived characters, organizing them into nested clades.
3. Compare the options: a linkage map shows gene positions on chromosomes, a karyotype displays chromosome number and structure, and a Punnett square predicts genetic crosses; none of these organize organisms by shared derived characters.
4. Conclude that the structure constructed by nesting clades characterized by shared derived characters is a cladogram, as it visually represents evolutionary relationships based on these traits.
5. Remember that cladograms help illustrate evolutionary pathways by grouping organisms into clades, which is fundamental in understanding phylogenetic relationships.