Phylogenetic Grouping Concepts

This video tutorial explains the different types of relationships on a phylogenetic tree, including monophyly, paraphyly, and polyphyly. Monophyly involves groups sharing a common ancestor and all its descendants. Paraphyly includes a common ancestor but not all descendants. Polyphyly groups unrelated species based on shared features rather than evolutionary origin. Examples for each type are provided using a theoretical phylogenetic tree.

What is the primary purpose of a phylogenetic tree?

• To categorize species by their habitat

• To list all known species

• To show the evolutionary relationships between taxa

• To display the physical features of species

Which of the following best describes a monophyletic group?

• A group with a common ancestor and some of its descendants

• A group with a common ancestor and all its descendants

• A group with no common ancestor

• A group based on shared physical features

In a phylogenetic tree, which taxa form a monophyletic group?

• A and B

• C and D

• G and H

• E and F

What defines a paraphyletic group?

• A group with a common ancestor and some of its descendants

• A group with a common ancestor and all its descendants

• A group with no common ancestor

• A group based on shared physical features

Which of the following is an example of a paraphyletic group?

• A, B, C, and D

• D, E, F, G, and H

• A, B, and C

• E, F, G, and H

What characterizes a polyphyletic group?

• A group with a common ancestor and all its descendants

• A group with a common ancestor and some of its descendants

• A group of unrelated species with no common ancestor

• A group based on genetic similarities

Why might species be grouped into a polyphyletic group?

• Due to shared evolutionary origins

• Because they share similar physical features

• Because they inhabit the same environment

• Due to genetic similarities

Which taxa could form a polyphyletic group?

• D and H

• A and B

• E and G

• C and F

What is the main difference between monophyletic and paraphyletic groups?

• Monophyletic groups are based on physical features, while paraphyletic groups are not

• Paraphyletic groups are based on physical features, while monophyletic groups are not

• Monophyletic groups include all descendants of a common ancestor, while paraphyletic groups do not

• Paraphyletic groups include all descendants of a common ancestor, while monophyletic groups do not

Which of the following statements is true about phylogenetic relationships?

• Monophyly, paraphyly, and polyphyly all refer to unrelated species

• Paraphyly includes all descendants of a common ancestor

• Polyphyly groups species based on shared physical features

• Monophyly excludes some descendants of a common ancestor