IB Biology HL A3.2.3 Hl Advantages of Evolutionary Classification Topic Practice

a. classification needed because of immense diversity of species/further study is facilitated/helps in identification of species;

b. (ideal) classification follows/is based on evolutionary relationships (between species that have a common ancestor);

c. (classification based on evolutionary relationships) allows characteristics of organisms within a group to be predicted because they are shared;

d. relationships can be inferred using different kinds of evidence such as morphology/development/molecular markers/presence/absence of genes/DNA/RNA/protein/amino acid sequences;

e. organisms that share similar structures/genetic sequences/DNA/RNA tend to be more closely related;

f. differences in (DNA/amino acid) sequence are due to mutation;

g. cladograms are branching diagrams/trees connected to a common ancestor

OR

the branches (in a cladogram) represent the evolutionary path of a group of organisms from a common ancestor;

h. cladograms are based on phylogeny/evolutionary relationships

OR

cladograms are built from multiple sequence alignments/ base sequences of genes / base sequences of amino acids in proteins;

Marking points for 9c continued on next page....

g. can be awarded
through a labelled
diagram.

8 max

.}

9.

c

i. a clade is a group of organisms that have evolved from a common ancestor

OR

a clade includes a single common ancestor and all of its descendants/all species evolved from it;

j. the root is the base of the cladogram / the hypothetical common ancestor of all the clades;

k. the node of the branch shows the most recent common ancestor between two species of a clade

OR

the node represents a (hypothetical) common ancestor

OR

the node is a branching point indicating that a group of organisms are related;

I. the terminal branches are ends that represent individual clades / species / group of closely related species;

j, k. and l. can be awarded in a
clearly annotated
diagram.