18.1 Finding Order in Diversity

Understand Key Concepts

1. The science of naming and grouping organisms is called

   1. anatomy.

   2. systematics.

   3. botany.

   4. paleontology.

2. Solely from its name, you know that Rhizopus nigricans must be

   1. a plant.

   2. an animal.

   3. in the genus Nigricans.

   4. in the genus Rhizopus.

3. A usefol classification system does NOT

   1. show relationships.

   2. reveal evolutionary trends.

   3. use different scientific names for the same organism.

   4. change the taxon of an organism based on new data.

4. In Linnaeus's system of classifying organisms, orders are grouped together into

   1. classes.

   2. species.

   3. families.

   4. genera.

5. The largest and most inclusive of the Linnaean taxonomic ranks is the

   1. kingdom.

   2. order.

   3. phylum.

   4. domain.

6. Why do biologists assign each organism a universally accepted name?

7. Why is species the only Linnaean rank defined “naturally”?

8. What features of binomial nomenclature make it usefol for scientists of all nations?

9. What is a taxon?

Think Critically

10. Apply Concepts What is a major problem with traditional classification? Give an example that demonstrates this problem.

11. Use Analogies Why is it important for a supermarket to have a classification scheme for displaying the foods that it sells?

12. Classify Venn diagrams can be used to make models of hierarchical classification schemes. A Venn diagram is shown below. Four groups are represented by circular regions—A, B, C, and D. Each region represents a collection of organisms or members of a taxonomic level. Regions that overlap, or intersect, share common members. Regions that do not overlap do not have members in common. Use the following terms to label the regions shown in the diagram: kingdom Animalia, phylum Chordata, class Insecta, and class Mammalia.

18.2 Modern Evolutionary Classification

Understand Key Concepts

13. A group that is limited to a common ancestor and all of its descendants is called a

    1. taxon.

    2. phylogeny.

    3. tree of life.

    4. monophyletic group.

14. A specific trait that is used to construct a cladogram is called a

    1. taxon.

    2. structural feature.

    3. clade.

    4. derived character.

15. A branch of a cladogram that consists of a single common ancestor and all the descendants of that ancestor is called

    1. cladistics.

    2. a kingdom.

    3. a clade.

    4. a class.

16. What does each individual node in a cladogram represent?

17. Why can differences in mitochondrial DNA be used as derived characters?

18. What is phylogeny?

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