Surface Area to volume ratio
The smaller an object or organism the larger the surface area to volume ratio. The more folds in the surface, the larger the surface area to volume ratio.
the above diagram shows this, the solid block has a smaller surface area to volume ratio than a pile of boxes making up a shape the same size.
Why is this important? If a biological process of benefit to us takes place at the surface of something, then the more surface the more opportunity for the process to take place.
Links:
Exams Tutor
Modelling Activity
Summary Site
Maths revision
Extension:
National Geographic - Different Size Dinosaurs