Question

How is a clade differentiated from another clade? a. a clade includes only the class and phylum for a group of organisms. b. a clade represents a significant divergence in evolutionary history and covers all organisms involved in that divergence. c. a clade is a biphyletic group in which there are two branching points for each group of organisms. d. a clade is a monophyletic grouping in which all the organisms stem from the same branching point.

Answer 1

A clade is a monophyletic group that includes an ancestor and all of its descendants, all stemming from the same branching point on a phylogenetic tree. It is identified using cladistics and cladograms that illustrate these evolutionary relationships.

Step-by-step explanation:

A clade is differentiated from another clade by being a monophyletic grouping. This means that a clade consists of an ancestor and all of its descendants, all stemming from a single point on a phylogenetic tree. Considering the options provided, the correct answer is (d): a clade is a monophyletic grouping in which all the organisms stem from the same branching point. This branching point is critical to the identification of a clade, as it represents a significant divergence in evolutionary history and signifies the point where one lineage splits into distinct new ones, a concept central to cladistics.

Clades can be identified using a cladogram, which visually represents evolutionary relationships and may contain multiple groups, as long as they all originated from the same ancestral lineage. When building phylogenetic trees, which use molecular and morphological data to map these relationships, we see that each clade originates from a singular branch point, while non-clade groups do not.

Answer 2

The correct answer is D: a clade is a monophyletic grouping in which all the organisms stem from the same branching point.

In biological classification, a clade represents a group of organisms that includes an ancestral species and all its descendants. This is a key concept in phylogenetics, the study of the evolutionary history and relationships among species.

Clades are identified by shared characteristics that are presumed to have been present in their common ancestor. This monophyletic nature distinguishes a clade from other groupings, such as paraphyletic or polyphyletic groups, which do not include all descendants of a common ancestor.