When viewed from the Z axis (above or below), why are aircraft wings often pointed as they get towards the wingtips instead of maintaining the same surface area for their entire length?

This seems to be a design change in the last 50-60 years, as earlier designs typically featured more rectangular wings.

Extra points if you can explain why some wings feature rounded tips, with the maximum protrusion halfway between fore and aft. This design was very common for biplanes.

When viewed from the Z axis (above or below), why are modern aircraft wings often pointed as they get towards the wingtips instead of maintaining the same surface area for their entire length?

This seems to be a design change in the last 50-60 years, as earlier designs typically featured more rectangular wings.

Extra points if you can explain why some rectangular wings feature rounded tips, with the maximum protrusion halfway between fore and aft of the wing. This design was very common for biplanes.

When viewed from the Z axis (above or below), why are aircraft wings often pointed as they get towards the wingtips instead of maintaining the same surface area for their entire length?

This seems to be a design change in the last 50-60 years, as previously designs featured more rectangular wings.

When viewed from the Z axis (above or below), why are aircraft wings often pointed as they get towards the wingtips instead of maintaining the same surface area for their entire length?

This seems to be a design change in the last 50-60 years, as earlier designs typically featured more rectangular wings.

Extra points if you can explain why some wings feature rounded tips, with the maximum protrusion halfway between fore and aft. This design was very common for biplanes.