Explanation:

The First-Past-the-Post (FPTP) system is a voting system used in many countries, including the United Kingdom, Canada, and India. Under this system, voters cast their vote for a single candidate, and the candidate with the most votes wins the seat. This system has some advantages, such as simplicity and familiarity, but it also has some drawbacks.

Bonus Seats:
One of the drawbacks of the FPTP system is that it often leads to a disproportionate allocation of seats in parliament. The system tends to favor larger parties or coalitions and can give them more seats than their share of the popular vote would warrant. This is known as the "bonus seats" effect.

The FPTP system is based on a winner-takes-all principle, meaning that the candidate with the most votes in a constituency wins the seat, regardless of the margin of victory. This can lead to situations where a party or coalition that receives a significant share of the vote but falls short of a majority can still win a majority of the seats in parliament.

Reasons for Bonus Seats:
There are several reasons why the FPTP system can result in bonus seats for the largest party or coalition:

1. Concentration of Support: The FPTP system tends to favor parties or coalitions that have concentrated support in specific regions or constituencies. Even if a party or coalition does not win the majority of votes nationally, they can win a majority of seats by winning a higher number of closely contested races.

2. Wasted Votes: In the FPTP system, votes cast for losing candidates are essentially wasted, as they do not contribute to the election of a representative. This can result in a significant number of wasted votes for smaller parties, while larger parties can accumulate votes more efficiently and win more seats.

3. Tactical Voting: The FPTP system can also lead to tactical voting, where voters strategically vote for a candidate they perceive to have a better chance of winning, rather than their preferred candidate. This can further amplify the advantage of larger parties or coalitions.

Impact:
The effect of bonus seats in the FPTP system is that the largest party or coalition often ends up with a greater number of seats than their share of the popular vote would suggest. This can lead to a distortion of representation in parliament, as smaller parties may be underrepresented or even excluded from the legislature altogether.

This disproportionality can impact the ability of smaller parties to influence policy-making and can result in a lack of diversity and pluralism in the political system. It can also lead to a perception of unfairness and a loss of confidence in the electoral process.

Conclusion:
In conclusion, the FPTP system often gives the largest party or coalition more seats than their share of the popular vote would allow, resulting in bonus seats. This can have implications for representation, diversity, and the overall fairness of the electoral system.