A proportional representation electoral system differs from a first-past-the-post system by distributing seats in the legislature based on the percentage of votes received by each party. Under proportional representation, even smaller parties can gain seats proportionate to their support, fostering a more representative political landscape. In contrast, the first-past-the-post system awards victory to candidates with the most votes in single-member districts, often leading to a two-party system and potential underrepresentation of diverse viewpoints, thereby affecting overall electoral fairness.