Fish Gills and Oxygen Uptake

Fish live in water, where oxygen levels are much lower than in air. To survive, they have specialized internal structures called gills, which extract dissolved oxygen from water as it passes over thin membranes.

Inside each gill are thousands of tiny filaments rich in capillaries - small blood vessels that absorb oxygen and release carbon dioxide. This structure gives gills a very large surface area, which is essential for efficient gas exchange.

Researchers from the Marine Life Physiology Institute measured how gill surface area affects oxygen uptake and fish activity levels in several species.

Fish with larger gill surface areas can extract more oxygen, supporting longer and more active swimming periods. This internal structure allows them to survive, find food, escape predators, and reproduce in aquatic environments.

This example shows how internal structures, such as gills, have specific functions that support survival and behavior. Fish depend on the design of their gills to live successfully underwater - a perfect model of structure supporting function.

Table 1.

Graph of Information - Figure 1.

Graph of Information - Figure 2.