Essential Idea:  The ancestry of groups of species can be deduced by comparing their base or amino acid sequences.

• Outline answer to each objective statement for topic 5.4 (coming soon)
• Quizlet study set for this topic

At SHS, Topic 5.4 is taught in the following class unit(s):​​​​​​

• Adaptations to Niches through Time
• Cladistics 

5.4.U1  A clade is a group of organisms that have evolved from a common ancestor.

• Define clade and cladistics.

5.4.U2  Evidence for which species are part of a clade can be obtained from the base sequences of a gene or the corresponding amino acid sequence of a protein.

• Outline the relationship between time, evolutionary relationships and biological sequences (nitrogenous base or amino acid).

5.4.U3  Sequence differences accumulate gradually so there is a positive correlation between the number of differences between two species and the time since they diverged from a common ancestor.​

• Outline the use of a “molecular clock” to determine time since divergence between two species.
• State the source of differences between biological sequences (nitrogenous base or amino acid).

5.4.U4  Traits can be analogous or homologous.​

• Contrast analogous and homologous traits.
• State an example of analogous and homologous traits.

5.4.U5  Cladograms are tree diagrams that show the most probable sequence of divergence in clades.​

• Define cladogram and node.
• Outline how computer programs analyze biological sequence data to create cladograms.
• Identify members of clades given a cladogram.

5.4.U6  Evidence from cladistics has shown that classifications of some groups based on structure did not correspond with the evolutionary origins of a group or species.​

• Outline the role of technological advancements in the development of cladistics.
• Explain why the development of cladistics lead to the reclassification of some species.

5.4.A1  Cladograms including human and other primates.

• Interpret a cladogram depicting primate species. ​

5.4.A2  Reclassification of the figwort family using evidence from cladistics.

• Outline the reason and evidence for the reclassification of the figwort family.

5.4.S1  Analysis of cladograms to deduce evolutionary relationships.​

• Analyze a cladogram to explain the evolutionary relationship between species.
• Discuss the use of cladograms as hypotheses of evolutionary relationships.

5.4.NOS  Falsification of theories with one theory being superseded by another- plant families have been reclassified as a result of evidence from cladistics.

• Outline the reason why biological theories may change with time.