Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Insects, such as cockroaches, do not have lungs. They possess small openings on the sides of their body called spiracles, which connect to a network of air tubes called tracheae. Air enters through spiracles and travels through the tracheae to reach all body tissues.
Earthworms breathe through their skin. The skin of an earthworm is moist and slimy, allowing gases like and to pass through it easily via the process of diffusion.
Fishes live in water and use specialized organs called gills for breathing. Gills are projections of the skin that are richly supplied with blood vessels. They help in utilizing the oxygen dissolved in water.
Frogs are amphibians and possess a dual respiratory system. On land, they breathe through their lungs like humans, but in water, they can breathe through their moist and slippery skin.
The basic process of releasing energy from food is called cellular respiration, which is common to all living organisms. The chemical reaction can be represented as: .
Whales and Dolphins are mammals that live in water. They do not have gills; they breathe through lungs. They come to the surface of the water regularly to breathe in air through blowholes (nostrils) located on the upper parts of their heads.
📐Formulae
💡Examples
Problem 1:
Why do fishes die when they are taken out of water?
Solution:
Fishes use gills to breathe oxygen dissolved in water. Gills cannot absorb directly from the air.
Explanation:
When a fish is taken out of water, the gill filaments collapse, and the surface area for gas exchange is drastically reduced. Since gills are not designed to take in gaseous oxygen from the atmosphere, the fish dies due to lack of .
Problem 2:
A cockroach is placed in a container filled with water such that its head is outside but its body is submerged. Will it survive?
Solution:
No, the cockroach will eventually die of suffocation.
Explanation:
Insects like cockroaches breathe through spiracles located on the sides of their abdomen and thorax, not through their mouth or head. Since the body (and thus the spiracles) is submerged in water, the entry of air into the tracheal system is blocked.