Concept and uses of classification systems：練習題

Which group of arthropods does the organism shown in the diagram belong to?

Two different organisms are classified within the same genus. What does this indicate about their DNA base sequences and evolutionary relationship compared to organisms in different genera?

The DNA base sequences of a specific gene were compared between Species X and three other species. The percentage of similarity is shown in the data below:

Species X and Species A: 97% similarity
Species X and Species B: 82% similarity
Species X and Species C: 65% similarity

Which species shared a common ancestor with Species X most recently?

Which of the following describes the binomial system for naming a species?

A mule is the sterile offspring of a male donkey and a female horse. Based on the biological definition of a species, what can be concluded about horses and donkeys?

State the biological term for a group of organisms that can reproduce to produce fertile offspring.

Describe the structure of a dichotomous key in terms of how it uses choices to identify an organism.

Explain why DNA base sequences are considered a more reliable tool for classification than morphological features in cases of convergent evolution.

A researcher is comparing three different species of plants. Species X and Y have very similar leaf shapes, while Species Y and Z have very similar DNA base sequences.

(a) Identify which two species are more closely related according to modern classification systems.
(b) Explain the relationship between the similarity of DNA base sequences and the time since two species shared a common ancestor.
(c) State the two parts of the binomial system used to name these species.

Classification systems have evolved from being based purely on morphology to incorporating molecular data to reflect evolutionary relationships.

(a) Explain the difference between the genus and the species in the binomial system, and state one internationally agreed rule for how these names must be written.
(b) Explain the relationship between the number of differences in DNA base sequences and the time elapsed since two species shared a common ancestor.
(c) Identify two features of cells that would allow a scientist to classify an organism into the prokaryote kingdom rather than the protoctist kingdom.