Summary
Gills, tracheae, book lungs and lungs exchange gases in aquatic and terrestrial animals.
In depth
Gills (countercurrent flow in fish extracts up to 80 to 90 percent of oxygen), tracheae (insects, air tubes to tissues), book lungs (spiders) and lungs with large surface area. Birds' air sacs give one-way flow.
Gas exchange surfaces need to be thin, moist and large. Countercurrent flow improves oxygen extraction in gills. Insects use spiracles.
Example: birds' lungs are more efficient than mammals'.
Oxygen uptake faces the problem that diffusion is slow, so animals use large, thin, moist surfaces and ventilation. Gills in water: fish pump water over gills in a direction opposite to blood flow (countercurrent), keeping a gradient across the whole lamella. Water holds little oxygen (about 3 percent of air) and is dense, so fish spend more energy on ventilating. Air-breathers use lungs: mammalian alveoli (about 300 million, 70 square metres of surface), bird parabronchi, and amphibian simple lungs and skin.
Insects use tracheae and spiracles, and large ones pump their abdomens for ventilation. Respiratory pigments such as haemoglobin, haemocyanin (copper-based, blue, in molluscs and arthropods) increase transport. Diving mammals store oxygen in myoglobin and blood; Weddell seals can stay under for 80 minutes.
Remember: countercurrent exchange is highly efficient and also used for heat and salt exchange.
Frequently asked questions
What is Animal Respiration?
Gills, tracheae, book lungs and lungs exchange gases in aquatic and terrestrial animals.
Which area of biology covers Animal Respiration, and how advanced is it?
Animal Respiration is one of the 53 topics in Zoology & Animal Diversity. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Vertebrates and Invertebrates, Animal Excretion, Ruminants.
Can you give an example of Animal Respiration?
Amphibians can absorb oxygen through skin.
What should I learn before Animal Respiration?
Work through the Beginner topics in Zoology & Animal Diversity first, such as Animal Kingdom, Vertebrates and Invertebrates, Sponges, then return to Animal Respiration. Intermediate topics assume the Beginner vocabulary.
What topics are related to Animal Respiration?
The closest topics to Animal Respiration are Vertebrates and Invertebrates, Animal Excretion, Ruminants, Amphibians. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Animal Respiration?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Animal Respiration. To practise the whole of Zoology & Animal Diversity, use the Zoology & Animal Diversity quiz.
How is Animal Respiration different from Vertebrates and Invertebrates?
Animal Respiration: Gills, tracheae, book lungs and lungs exchange gases in aquatic and terrestrial animals. Vertebrates and Invertebrates: Vertebrates have a backbone; invertebrates, which are over 95 percent of animals, do not. Read both side by side and note what each one explains.
How should I study Animal Respiration step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Vertebrates and Invertebrates and explain the difference aloud. Finally, take the Zoology & Animal Diversity quiz and come back to this page for any question you miss.