A3.2 Classification and Cladistics (HL Only)

Multiple Choice

Which of the following best describes the theme of 'Unity and Diversity' in the study of organisms?

• It focuses only on the similarities among organisms.

• It highlights both the similarities and differences among organisms.

• It studies only the differences among organisms.

• It ignores the evolutionary relationships among organisms.

Open Ended

Why is it important to classify organisms and study their evolutionary relationships?

Open Ended

How do cladistic methods differ from traditional taxonomic methods?

Open Ended

What tools are used to classify organisms into taxonomic groups?

Multiple Choice

Which of the following is an advantage of classification corresponding to evolutionary relationships?

• It groups organisms based on physical appearance only.

• It allows for the identification of evolutionary lineages.

• It ignores genetic differences between organisms.

• It classifies organisms randomly.

Multiple Select

Select all that are key terms related to classification and cladistics.

• Cladogram

• Molecular Clock

• Photosynthesis

• Node

Fill in the Blank

Classification is needed because of the immense diversity of ___ .

Multiple Choice

What is the main purpose of taxonomy in biology?

• To classify organisms into groups based on observable traits

• To name all living organisms

• To study the behavior of animals

• To create new species

Open Ended

Why is classification important for studying the diversity of species on Earth?

Multiple Select

Which of the following are reasons why the traditional hierarchy of taxa can be problematic?

• It does not always reflect evolutionary divergence

• It is based on observable physical traits only

• It uses a fixed ranking system

• It always matches evolutionary relationships

Fill in the Blank

The most specific taxon in the traditional hierarchy is ___.

Multiple Choice

Which sequence correctly represents the hierarchy of taxa from broadest to most specific?

• Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

• Kingdom, Domain, Phylum, Class, Order, Family, Genus, Species

• Domain, Kingdom, Class, Phylum, Order, Family, Genus, Species

• Domain, Phylum, Kingdom, Class, Order, Family, Genus, Species

Open Ended

Explain why reptiles do not exist as a valid group according to cladistics.

Fill in the Blank

Fill in the blank: Cladistics groups organisms into clades, where all members share a common ___.

Multiple Choice

Which of the following best describes a paradigm shift in the context of biological classification?

• A minor adjustment in classification criteria

• A fundamental change from classifying organisms by arbitrary taxa to grouping them by common ancestry

• A shift from using genetic data to using physical traits

• A change from grouping plants and animals together

Open Ended

How does Darwin’s sketch of the tree of life illustrate the relationship between classification and evolution?

Open Ended

Explain why classifying organisms based on evolutionary relationships is considered advantageous. Use information from the slides to support your answer.

Multiple Select

Which of the following statements about clades is/are correct?

• All members of a clade have evolved from a common ancestor.

• Cladograms show probable divergence between species.

• Clades can only include living organisms.

• Cladistics is based solely on observable traits.

Multiple Choice

Which of the following best describes a clade?

• A group of organisms with similar habitats

• A group of organisms with a common ancestry and shared traits

• A group of organisms with the same physical appearance

• A group of organisms that live in the same region

Multiple Choice

What is the most objective evidence for placing organisms in the same clade?

• Morphological traits

• Base sequences of genes or amino acid sequences of proteins

• Geographical distribution

• Behavioral similarities

Fill in the Blank

Fill in the blank: Mutations accumulate gradually over long periods of time at a constant rate, so they can be used as ________ clocks.

Open Ended

Explain how the molecular clock is used to estimate when clades diverged from a common ancestor.

Multiple Select

Select all the limitations of molecular clocks mentioned in the slides.

• Generation time

• Population size

• Selective pressure

• Geographical isolation

Multiple Choice

Which of the following factors can affect the accuracy of molecular clocks?

• Generation time

• Population size

• Selective pressure

• All of the above

Open Ended

How do you think the concept of cladistics helps us understand the unity and diversity of organisms?

Open Ended

What is one key idea you learned about classification and cladistics in this lesson?