To apply parsimony to constructing a phylogenetic tree, a. choose the tree that assumes all evolutionary changes are equally probable. b. choose the tree in which the branch points are based on as many shared derived characters as possible. c. choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology. d. choose the tree with the fewest branch points.

Verified step by step guidance

1. Understand the concept of parsimony in phylogenetics, which is a method used to infer relationships among species by finding the simplest explanation for observed data, typically minimizing the number of evolutionary changes.
2. Review each option to determine how it relates to the principle of parsimony: a) assumes all changes are equally probable does not necessarily minimize changes, b) based on shared derived characters focuses on commonality rather than simplicity, c) represents the fewest changes aligns with minimizing evolutionary changes, d) fewest branch points does not directly relate to the number of changes.
3. Identify that option c) choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology, directly addresses the principle of parsimony by minimizing the total number of evolutionary changes.
4. Recognize that minimizing changes (option c) is more aligned with parsimony than simply minimizing branch points (option d), as fewer branch points do not necessarily equate to fewer evolutionary changes.
5. Conclude that the best choice to apply parsimony in constructing a phylogenetic tree is option c) choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology.

Key Concepts

Parsimony in Phylogenetics

Parsimony is a principle used in phylogenetics to select the simplest explanation or tree that requires the least number of evolutionary changes. This approach assumes that the most likely evolutionary pathway is the one that minimizes the total number of changes, whether in DNA sequences or morphological traits. By favoring simpler trees, parsimony helps avoid overfitting the data with unnecessary complexity.

Shared Derived Characters

Shared derived characters, or synapomorphies, are traits that are present in a group of organisms but absent in their distant ancestors. These characters are crucial for constructing phylogenetic trees as they provide evidence of common ancestry and help define evolutionary relationships. The more shared derived characters two species have, the more closely related they are likely to be.

Phylogenetic Tree Construction

Constructing a phylogenetic tree involves organizing species based on their evolutionary relationships, often using data from morphology or genetic sequences. The tree is a visual representation of these relationships, with branch points indicating common ancestors. The goal is to accurately reflect the evolutionary history of the organisms, which can be achieved through methods like parsimony, maximum likelihood, or Bayesian inference.