Embedded Files
Teaching time: 3 hours Practical time: 1 hour
Teaching time: 3 hours Practical time: 1 hour
key vocabulary
key vocabulary
Prior learning and retrieval practice
Prior learning and retrieval practice
Review topic 5.3 classification
Review topic 3.1 genes
Cladograms
Cladograms
U1: A clade is a group of organisms that have evolved from a common ancestor.
S1: Analysis of cladograms to deduce evolutionary relationships.
A1: Cladograms including humans and other primates.
Exercise 1: Identify the clades in the diagrams below and mark their common ancestors. Deduce the homologous features that suggest decent from a common ancestor
Deducing relationships in clades
Deducing relationships in clades
Essential idea: The ancestry of groups of species can be deduced by comparing their base or amino acid sequences.
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.
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.
U4: Traits can be analogous or homologous.
U5: Cladograms are tree diagrams that show the most probable sequence of divergence in clades.
Exercise 2: work through the exercises in the google doc
Constructing Cladograms
Constructing Cladograms
Practical
Linking to Topic 3.1: Once DNA sequences have been aligned in clustal X you can create a phylogenetic tree that can be viewed in NJplot. I think that this would make an excellent area for a student to conduct an IA in. They could look at how different genes compare across the same species in determining evolutionary relationships.
Reclassification of organisms based on genetic data
Reclassification of organisms based on genetic data
NoS: Falsification of theories with one theory being superseded by another—plant families have been reclassified as a result of evidence from cladistics. (1.9)
A2: Reclassification of the figwort family using evidence from cladistics.
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.
Download more (free) resources for this topic from my TES shop
Download more (free) resources for this topic from my TES shop
Google Sites
Report abuse