The Following Questions Refer to the Evolutionary Tree in Figure

question 39

Multiple Choice

The following questions refer to the evolutionary tree in Figure 22.2.
The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V-Z) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.

Figure 22.2
-Which of the five common ancestors, labeled V-Z, has been least successful in terms of the percent of its derived species that are extant?

• A) V
• B) W
• C) X
• D) Y
• E) Z

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Definitions:

Organelles

Specialized structures within a cell that perform distinct processes, like the nucleus, mitochondria, and chloroplasts.

Eukaryotic Organelle

Structurally defined intracellular compartments in eukaryotic cells, each with specialized functions, like the nucleus or mitochondria.

Nucleus

A membrane-bound organelle found in eukaryotic cells that contains most of the cell's genetic material and regulates gene expression and cell division.

Chloroplast

The organelle found in plant cells and some algae that is responsible for photosynthesis.