Activity 6.6 biology class 10
Answers
Here is the solution.
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Q.1. Observe fish in an aquarium. They open and close their mouths and the gill-slits (or the operculum which covers the gill-slits) behind their eyes also open and close. Are the timings of the opening and closing of the mouth and gill-slits coordinated in some manner?
Answer --> Yes, the timings of the opening and closing of the mouth and gill-slits are coordinated. They open and close alternatively.
Q.2. Count the number of times the fish opens and closes its mouth in a minute.
Answer --> This varies from fish to fish, size and state of activities under taken by fish. [Observe yourself]
Q.3. Compare this to the number of times you breathe in and out in a minute.
Answer --> As availability of oxygen is much less in dissolved form in water than in open air, therefor fish breaths at higher rate than us to full fill the demand for respiration
Answer:
Activity 6.6 NCERT class 10 science chapter 6 Life processes
Brief procedure:
Activity 6.6 asks us to look at gills and mouth of fishes and observe how many time they open and close in a minute.
Observation:
The breathing rate of fish is more than us.
Explanation:
Organisms like fishes, animals and humans require oxygen to meet its energy demand. They do this by taking either oxygen dissolved in water as in fish or oxygen present in air by the lungs.
Oxygen is not highly soluble in water. Due to this the amount of oxygen in water is lesser (9mg/ltr). So to meet the demand for oxygen fish opens and closes its mouth and gills more frequently which is around 90 to 100 times a minute.
Atmospheric air contains a significant amount of oxygen (21%). So we need a lesser rate of breathing to fulfil our needs. As a result, human respiratory rate is only 12 to 20 breaths per minute.