Breathing Under Water
Key Notes :
Introduction to Aquatic Respiration
- Breathing underwater is essential for aquatic animals, and they have specialized respiratory systems to do so.
- Unlike land animals that breathe oxygen from the air, aquatic animals extract oxygen from water.
Gills as Respiratory Organs
- Most aquatic animals, such as fish, breathe through gills.
- Gills are specialized organs that filter dissolved oxygen from water.
- Water passes over the gill membranes, and oxygen is absorbed into the bloodstream while carbon dioxide is expelled.
Oxygen Dissolved in Water
- Water contains dissolved oxygen, though in lower concentrations than air.
- The concentration of dissolved oxygen varies based on factors like water temperature and salinity.
How Gills Work
- Gills have a large surface area and thin membranes, which allow for efficient gas exchange.
- Blood in the gills flows in the opposite direction to water (counter-current exchange), maximizing oxygen absorption.
Breathing Methods in Other Aquatic Animals
- Amphibians (e.g., frogs): They can breathe through their skin when underwater, a process known as cutaneous respiration.
- Marine mammals (e.g., whales, dolphins): They have lungs and must come to the surface to breathe air.
Adaptations for Breathing Under Water
- Many fish species have developed additional features such as air bladders to regulate buoyancy and assist in breathing.
- Some aquatic insects use air bubbles trapped under their wings to breathe underwater.
Human Challenges in Breathing Under Water
- Humans cannot breathe underwater because we lack gills and must use artificial equipment like scuba gear for underwater breathing.
- Scuba gear provides compressed air that humans can inhale while submerged.
Let’s practice!
