IB Biology HL A4.1.2 Evidence From Sequences Questions

Use DNA, RNA and protein sequence evidence to infer common ancestry, phylogeny and divergence.

Exam points

Use DNA, RNA, amino-acid or protein sequences to infer common ancestry and evolutionary relatedness.
Interpret sequence identity and differences as molecular evidence for phylogeny, divergence or an evolutionary clock.

[Maximum number: 4]

Proteins play essential roles in all forms of life.

Describe how a protein that is common to many organisms can be used in evolutionary studies.

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a	amino acid sequence of the protein from each organism is compared;
b	changes in (base/amino acid) sequence accumulate over time;
c	due to mutation;
d	positive correlation between number of (base/amino acid) differences between (two) species and time they diverged from a common ancestor OR fewer the (base/amino acid) differences, the less time since diverged from a common ancestor / more closely related;
e	cladograms illustrate probable sequence of divergence/evolutionary origins;
f	accumulation of mutations can be used as a molecular clock/allows time since evolutionary divergence to be estimated;