Summarize the text about the "timeline of life" assignment.

This is an assignment about the evolution of arthropods, from marine worms to butterflies. The task is to create a colorful "timeline of life" (horizontal or vertical) with drawings and captions. The student needs to take a sheet of A4 paper, draw a "timeline" (an arrow pointing from left to right) in the center or across the entire sheet. On this timeline, they must mark 6 key stages of arthropod evolution:

• Ancestral group: ancient polychaete annelid worms (schematic drawing of a worm with parapodia).
• First arthropods: trilobites (drawing of a trilobite with body segments).
• Transition to land: appearance of tracheal respiration and a chitinous exoskeleton (draw an ancient spider or scorpion).