(a) We yawn when we feel sleepy. Why?
(b) Rachit is studying respiration in amphibians. His specimen to study is frog. Help Rachit study
the various modes of respiration in frogs.
(c) Whales and dolphins often come up to the water surface. They even release a fountain of
water sometimes while moving upwards. Why do they do so?
Answers
Explanation:
A.One is that when we are bored or tired, we just don't breathe as deeply as we usually do. As this theory goes, our bodies take in less oxygen because our breathing has slowed. Therefore, yawning helps us bring more oxygen into the blood and move more carbon dioxide out of the blood
b.Studies of evening grosbeaks and ring-billed gulls show that their ventilation, in contrast to that of pigeons, increases in proportion to oxygen ...
Missing: Rachit specimen
(a) Often when a person is tired he or she takes a deep breath, which we call yawning. Yawning allows us to quickly increase the amount of oxygen in the blood. Oxygen diffuses through the blood vessels inside the lungs directly into the blood stream. This increase in oxygen may help make us more alert.
(b) Due to amphibious mode of life, frog shows different modes of respiration.
1. Gills : At the larval stage of their development, frogs lack functional lungs but are able to take in oxygen through a set of gills. A newly hatched tadpole's gills are external. These gills take in oxygen when water passes over them. As the tadpole matures, the gills are absorbed by the body and become an internal part of the tadpole's anatomy.
2. Lungs : Frogs rely on their lungs to breathe when they are active and need more oxygen than skin respiration alone can provide. Unlike mammals that draw air continuously into their lungs, frogs only breathe through lungs when necessary.
3. Skin : Though they have functional lungs, much of a frog’s respiration occurs through the skin. A frog’s moist skin is thin and marbled with blood vessels and capillaries close to the surface. The moisture on the skin dissolves oxygen from the air and water surrounding the frog and transmits it into the blood. Glands in the frog’s skin produce mucus that keeps the skin moist and allows for respiration even on dry land.
4. Mouth : Frogs have an additional surface for respiration other than their skin -- the moist lining of the mouth. When the frog's mouth is not submerged completely in water, this respiratory lining is in constant use, bringing oxygen into the bloodstream from the surrounding air and diffusing excess carbon dioxide back into the environment.
(c) Like other mammals, Even dolphins and whales respiratory organs are Lungs. So they have to come to the surface of the water regularly. The nostrils of whales and dolphins are located at the top of their heads called as Blowholes. So they exhale and inhale air through these blowholes. Hence, their exhalation looks like releasing fountain of water.