Why Humans Don't Have Gills?

The "Why Humans Don’t Have Gills" activity demonstrates how gill-like structures work in water but not in air. By attaching cloth strips to pencils and dipping them in water, students observe the increased surface area as strips separate. When removed from the water, the strips collapse, showing why gills, which need water to stay open and functional, are impractical for land animals. 

Learning Objective:

To explore how respiratory structures like gills are adapted to aquatic environments, and why land animals require different respiratory systems. 

Keywords:

Respiration, Gills, Surface area, Adaptation, Aquatic vs. terrestrial animals, Gas exchange, Evolution