ACT science practice test 38

Directions: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.

You are NOT permitted to use a calculator on this test.


The scientific classification of organisms provides information about the relative level of relatedness between species. Biologists use a hierarchical grouping system to classify organisms into various taxa (groups) based on shared physiological, developmental, and genetic characteristics. Table 5.5 identifies the scientific classification of five common species.

TABLE 5.5 Taxonomic Classification

Biologists use a phylogenetic tree to illustrate the evolutionary history of related species. In a typical tree, currently living species called extant taxa are listed along the right. Moving to the left, the point at which two or more extant taxa meet is called a node. A node indicates an ancestral taxon, or a common ancestor shared by the extant taxa.

Horizontal line length in a phylogenetic tree indicates relative divergence time, an estimation of how long ago the extant taxa are thought to have diverged into separate species. Figure 5.6 shows a phylogenetic tree of the species listed in Table 5.5.

Figure 5.6

1. The phylogenetic tree in Figure 5.6 identifies evolutionary relationships between which type of organisms?

A. Mammals
B. Arthropods
C. Invertebrates
D. Amphibians

2. To which family does Panthera pardus belong?

A. Mustelidae
B. Canidae
C. Felidae
D. Carnivora

3. All organisms in Table 5.5 are members of the same:

A. genus.
B. order.
C. species.
D. family.

4. Canis latrans is the scientific name of which organism?

A. American badger
B. Gray wolf
C. Leopard
D. Coyote

5. According to Figure 5.6, the European otter is most closely related to which species?

A. Panthera pardus
B. Canis lupus
C. Taxidea taxus
D. Canis latrans

6. According to Figure 5.6, how many common ancestors does Panthera pardus share with Taxidea taxus?

A. Three
B. One
C. Two
D. Four

7. According to Figure 5.6, which pair of species have the most recent divergence time?

A. Lutra lutra and Panthera pardus
B. Canis latrans and Lutra lutra
C. Taxidea taxus and Lutra lutra
D. Canis lupus and Canis latrans

8. Based on the information in the passage and Figure 5.6, Taxidea taxus would be considered:

A. an extant taxon.
B. a node.
C. an ancestral taxon.
D. an order.

9. Which of the following inferences can be made about the seven-level classification system used in Table 5.5?

A. Organisms classified in the same kingdom are classified in the same phylum.
B. Organisms within the same class share a common kingdom and phylum.
C. Organisms that share a common order cannot be classified in the same family.
D. Organisms within the same family must share a common genus and species.

10. The scientific classification of the lynx is shown in Table 5.6. With which species would the lynx share the most recent ancestor?

TABLE 5.6 Lynx Classification

A. Lutra lutra
B. Canis latrans
C. Panthera pardus
D. Taxidea taxus

11. How many taxonomic levels does the lynx have in common with the gray wolf ?

A. One
B. None
C. Two
D. Four

12. Based on the information in Table 5.5, it can be predicted that the common ancestor shared by all five species belonged to which taxon?

A. Mustelidae
B. Carnivora
C. Canidae
D. Felidae

13. A clade is the taxonomic term for a grouping composed of all the descendants of a single ancestral taxon. According to Figure 5.6, which of the following groupings would not constitute a clade?

A. Canis latrans and Canis lupus
B. Taxidea taxus and Lutra lutra
C. Canis latrans, Canis lupus, and Lutra lutra
D. Canis latrans, Canis lupus, Taxidea taxus, and Lutra lutra

14. The wolverine (Gulo gulo) belongs to the family Mustelidae. Which of the following assumptions can be made about the wolverine?

A. It is most closely related to the American badger.
B. It shares the most genetic similarity with the European otter.
C. It belongs to the same family as the gray wolf.
D. It belongs to the same order as the coyote.

15. Which of the following statements is best supported by the information in Figure 5.6?

A. The Canidae taxon diverged from the Mustelidae taxon more recently than from the Felidae taxon.
B. Canidae, Mustelidae, and Felidae all diverged into separate taxa at the same time.
C. The Mustelidae taxon diverged from the Felidae taxon more recently than from the Canidae taxon.
D. The Felidae taxon first diverged from the Canidae taxon and then from the Mustelidae taxon.