Cladistics Worksheet
A Grade 12 science worksheet covering the principles of cladistics, including cladogram interpretation, synapomorphies, and phylogenetic relationships.
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Standards
Topics
Cladistics: Understanding Evolutionary Relationships
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Read each question carefully and provide your best answer. Some questions may refer to the cladogram provided.
Observe the cladogram below and answer the following questions.
1. Which organisms are most closely related according to this cladogram?
2. What is the shared derived character (synapomorphy) that distinguishes the group containing organisms X and Y from organism Z?
3. Which of the following best describes a synapomorphy?
A shared ancestral character
A unique character found only in one species
A shared derived character
A character that has evolved multiple times independently
4. In cladistics, a monophyletic group includes:
An ancestor and some, but not all, of its descendants
An ancestor and all of its descendants
Two or more ancestors and their descendants
A group of organisms that share no common ancestor
5. A is a diagram that shows evolutionary relationships among organisms.
6. The principle of suggests that the simplest explanation for phylogenetic relationships is usually the best.
7. An outgroup is a species or group of species that is closely related to the ingroup but has diverged before the ingroup.
True
False
8. Homoplasy refers to a shared character state that has not been inherited from a common ancestor.
True
False
9. Briefly explain the difference between homology and analogy in the context of cladistics.
10. Why is it important to distinguish between shared ancestral characters (plesiomorphies) and shared derived characters (synapomorphies) when constructing a cladogram?