Prepared By

Mr. Chander Shekhar , JNV Jind

NVS NOIDA

E-CONTENT PREPARATION

CLASS – VII -SCIENCE

CHAPTER – 7

Weather, Climate and Adaptations of Animals to Climate

LEARNING OUTCOMES

By the end of the chapter, students should be able to:

1. Define cellular respiration and breathing

2. Differentiate between aerobic and anaerobic respiration

3. Describe respiratory system in human and process of breathing

4. Know the respiratory system in other organisms and plants.

5. Sketch respiratory system of humans and other animals

WHY DO WE RESPIRE ?

• All the living organisms are made up of small microscopic units called the cells.
• These cells have different functions to perform in these organisms such as digestion, respiration, transportation and excretion.
• The cells can perform this function only if they get the energy to do so.
• Hence, all living organisms need food which gives them the required energy.
• The energy present in the food gets released when the organisms respire or breathe.

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CELLULAR RESPIRATION

TYPES OF RESPIRATION

DIFFERENCE BETWEEN AEROBIC AND ANAEROBIC RESPIRATION

WHY DO MUSCLE CRAMPS ARISE AFTER A HEAVY EXERCISE ?�

• The cramps occur when muscle cells respire anaerobically. The partial breakdown of glucose produces lactic acid. The accumulation of lactic acid in muscles causes muscle cramps.

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HOW DO WE BREATHE ?

• We get oxygen by breathing in air and we remove carbon dioxide from the body by breathing out.

Breathing can be defined as a process in which organisms, , take in the oxygen-rich air present in the surroundings and release out air that contains high amount of carbon dioxide in it.

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INHALATION AND EXHALATION

• Inhalation is the process of taking the air that contains oxygen inside the body.
• Exhalation is a process of releasing out air that contains carbon dioxide out of the body. Inhalation and exhalation take place alternatively in the breathing process.

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ACTIVITY :-

• Take a wide plastic bottle. Remove the bottom. Get a Y-plastic tube. Make a hole in the lid so that the tube may pass through it. To the forked end of the tube fix two deflated balloons. Introduce the tube into the bottle as shown in. Now cap the bottle. Make it airtight. To the open base of the bottle, tie a thin rubber using a large rubber band.
• Pull the rubber sheet from the base downwards and watch the balloons. Next, push the rubber/plastic sheet up and observe the balloons.
• What do the balloons in this model represent? What does the rubber sheet represent?

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BREATHING RATE

• Breathing rate can be defined as the number of times a person breathes in a minute.

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OUR RESPIRATORY SYSTEM�

• Humans breathe in oxygen rich air and breathe out carbon dioxide rich air with the of nose, nasal cavity, larynx, trachea, bronchi and lungs. Lungs are protected by ribcage. Just below the lungs diaphragm is there.

PROCESS OF BREATHING

RESPIRATION IN FISHES

• Breathing underwater
• Animals that live underwater have special respiratory organs called gills.
• They are a comb-like structure present on the skin of these animals.
• Gills allow the exchange of gases between animals and the water easily.

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RESPIRATION IN INSECT

• Breathing in cockroach:
• Many insects like Cockroaches have small openings called spiracles present on the sides of the bodies.
• Also, they have an air tube-like structure called the trachea that allows the exchange of gases in these insects.
• The air enters the body through the spiracles and diffuses in the cells via the trachea.
• Similarly, the air from the cells enters the trachea and moves out of the body through spiracles.

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RESPIRATORY SYSTEM IN EARTHWORM

• Breathing in earthworms:
• Earthworms have a soft, slimming and moist skin.
• Hence the gases can easily pass in and out of the earthworm through its skin.
• Similarly, frogs also have a slippery and moist skin that can help in breathing. However, frogs contain lungs too.

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RESPIRATORY SYSTEM IN PLANTS

• 1.Plants also respire. They take in the carbon dioxide present in the atmosphere and use it in the photosynthesis, they release out oxygen in the environment.
• 2. All the parts of the plants can independently respire that is they can take in the carbon dioxide and release oxygen on their own.
• 3. The leaves of the plants have stomata. The allow gases exchange.
• 4. The woody stems of the plants also respire with the help of Lenticels.
• 5. The roots of the plants have root hairs. Hence they can absorb the air present in the soil.

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SUMMARY OF RESPIRATION IN ORGANISMS

• Respiration is essential for survival of all living organisms. It releases energy.
• The breakdown of glucose occurs in the cell of an organisms and release energy is called cellular respiration. When this happen in the presence of oxygen called aerobic respiration and in the absence of air called anaerobic respiration.
• Breathing (Inhalation + Exhalation ) : Breathing Rate- Numbers of breathing per minute – Normally 15-18 in a healthy person.
• Inhaled air passes through our nostrils into nasal cavity and then into lungs through pharynx, larynx, trachea, bronchus, bronchiole and finally alveoli.
• Earthworm : through their moist and slimy skin
• Insect : Through spiracles and trachea of the entire body.
• Fish : respire through their gills.

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SOME SPECIFIC WEB -LINKS

• geneo.in
• aglasem.com
• cbseacademic.nic.in
• pathshala app
• nistha app
• ncert.nic.in
• meritnation.com
• examfear.com
• e-shiksha
• jagranjosh.com

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THANK YOU