Paper 2 style question on topic 5.4 Cladistics
Use the buttons to review the topic, try a paper 2 style question and check your answer.Summary list for topic 5.4 Cladistics
- A clade is a group of organisms that have evolved from a common ancestor.
- Evidence for species of a clade can be
- the base sequences of a gene or
- the amino acid sequence of a protein.
- There is a gradual accumulation of differences and a positive correlation between the number of differences between two species and the time since they diverged from a common ancestor.
- Cladograms are tree diagrams that show the most probable sequence of divergence in clades.
- 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.
- Traits can be analogous (due to convergent evolution) or homologous (inherited from a common ancestor).
Skills (can you ....)
- Interpret and deduce relationships from cladograms including humans and other primates.
- Appreciate that in the light of new evidence some cladograms are changed.
- For example the reclassification of the figwort family using evidence from cladistics.