Class 7 : Science – ( English ) : Lesson 9. Life Processes in Animals

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On December 11, 2025

EXPLANATION AND ANALYSIS

🧭 All living animals carry out certain basic activities to stay alive.
These activities are called life processes.
They include nutrition 🍽️, respiration 🌬️, circulation ❤️‍🩹, and excretion 🚽.
🧠 Life processes keep the body functioning properly.
Without them, growth, repair, and survival would not be possible.
🔍 Understanding life processes helps us know how animals obtain energy, use it, and remove waste.

🧪 Nutrition is the process by which animals take in food and use it for energy, growth, and repair.
Animals cannot make their own food like plants 🌿.
They depend on plants or other animals for nutrition.
🧠 Animals are classified based on their food habits.
Herbivores 🐄 eat plants.
Carnivores 🦁 eat other animals.
Omnivores 🐻 eat both plants and animals.

🍽️ The process of nutrition in animals involves several steps.
Ingestion — taking in food
Digestion — breaking down food
Absorption — nutrients enter blood
Assimilation — nutrients are used
Egestion — removal of undigested food
🧠 Each step is important for proper nourishment.

🫀 Digestion breaks complex food into simpler substances.
This allows nutrients to be absorbed easily.
🧠 In humans, digestion begins in the mouth 👄.
Teeth chew food.
Saliva starts chemical digestion 🧪.

🧠 Food then moves to the stomach 🫃.
Here, digestive juices act on food.
Proteins are broken down.
🧠 Digested food passes to the intestine, where absorption occurs.

🧬 Respiration is the process of releasing energy from food.
Animals need energy for movement, growth, and repair ⚡.
🧠 Oxygen is required for respiration.
Animals breathe in oxygen and breathe out carbon dioxide 🌬️.

🐟 Different animals breathe in different ways.
Fish use gills 🐟.
Insects use spiracles 🐜.
Mammals use lungs 🫁.
🧠 This adaptation helps animals survive in their environment.

❤️ Circulation is the transport of food, oxygen, and wastes inside the body.
Blood 🩸 plays a key role in circulation.
🧠 The heart ❤️ pumps blood throughout the body.
Blood vessels carry materials to and from cells.

🧠 Blood contains red cells, white cells, and platelets.
Each has a specific function.
Together they keep the body healthy.

🚽 Excretion is the removal of waste materials from the body.
Waste products are harmful if allowed to accumulate ⚠️.
🧠 Kidneys 🫀 remove waste from blood.
Urine carries wastes out of the body.

🧭 Different animals remove waste in different ways.
Aquatic animals 🐠 release waste into water.
Land animals use special organs.
🧠 Excretion keeps the internal environment clean and balanced.

🧠 Life processes are interconnected.
Digestion provides nutrients.
Respiration releases energy.
Circulation distributes materials.
Excretion removes waste.
🧠 All processes work together for survival.

🌍 Life processes vary among animals.
Adaptations depend on habitat 🌊🌳.
Structure and function are linked.
🧠 These variations show the diversity of animal life.

🧭 Studying life processes builds scientific understanding.
It explains body functions.
It improves health awareness 🩺.
It encourages respect for living beings.

📜 Life processes continue throughout an animal’s life.
They maintain balance and ensure survival.
🚀 Understanding them forms the foundation of biology.

📝 Summary of the Lesson
Life processes are essential activities that keep animals alive. These include nutrition, respiration, circulation, and excretion. Animals depend on plants or other animals for food. Digestion breaks food into simpler substances that can be absorbed and used by the body. Respiration releases energy from food using oxygen. Circulation transports nutrients, gases, and wastes throughout the body, while excretion removes harmful waste products. Different animals show different adaptations for these processes based on their habitat. All life processes work together to maintain balance and support survival. Understanding these processes helps us appreciate how animal bodies function.

⚡ Quick Recap
⭐ Life processes support survival
⭐ Animals depend on food for energy
⭐ Digestion breaks down food
⭐ Respiration releases energy
⭐ Circulation transports materials
⭐ Excretion removes waste
⭐ All processes work together

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TEXTBOOK QUESTIONS

🔒 ❓ Question 1
Complete the journey of food through the alimentary canal by filling up the boxes with appropriate parts.
Food → Mouth → _ → Stomach → → ___ → Anus
📌 Answer:
Food → Mouth → Oesophagus → Stomach → Small intestine → Large intestine → Anus
🔹 Food is chewed in the mouth.
🔹 It passes through the oesophagus to the stomach.
🔹 Digestion and absorption mainly occur in the small intestine.
🔹 Waste is collected in the large intestine and removed through the anus.

🔒 ❓ Question 2
Sahil placed pieces of chapati in test tube A. Neha placed chewed chapati in test tube B. Santushti placed boiled and mashed potato in test tube C. All added iodine solution. What were their observations? Give reasons.
📌 Answer:
🔹 Test tube A (pieces of chapati):
The solution turns blue-black.
➡️ Chapati contains starch, which reacts with iodine.
🔹 Test tube B (chewed chapati):
The blue-black colour is lighter or may not appear strongly.
➡️ Saliva contains amylase, which begins breaking starch into sugar.
🔹 Test tube C (boiled and mashed potato):
The solution turns deep blue-black.
➡️ Potato is rich in starch, and boiling does not remove starch.

🔒 ❓ Question 3
What is the role of the diaphragm in breathing?
(i) To filter air
(ii) To produce sound
(iii) To help in inhalation and exhalation
(iv) To absorb oxygen
📌 Answer:
✔️ Correct option: (iii) To help in inhalation and exhalation
🔹 The diaphragm contracts and moves downward during inhalation, increasing chest space.
🔹 It relaxes and moves upward during exhalation, reducing chest space.
🔹 This movement helps air enter and leave the lungs.

🔒 ❓ Question 4
Match the following.
Name of the part Function
(i) Nostrils (a) Fresh air from outside enters
(ii) Nasal passages (d) Tiny hair and mucus trap dust
(iii) Windpipe (e) Air reaches lungs through this part
(iv) Alveoli (b) Exchange of gases occurs
(v) Ribcage (c) Protects lungs
📌 Answer:
(i) Nostrils → (a)
(ii) Nasal passages → (d)
(iii) Windpipe → (e)
(iv) Alveoli → (b)
(v) Ribcage → (c)

🔒 ❓ Question 5
Anil claims that respiration and breathing are the same. What questions can Sanvi ask to show he is incorrect?
📌 Answer:
Sanvi can ask:
🔹 Does breathing release energy?
🔹 Can respiration occur without breathing in cells?
🔹 Is oxygen always directly inhaled during respiration?
➡️ Breathing is the physical process of inhaling and exhaling air.
➡️ Respiration is a chemical process where food is broken down to release energy.

🔒 ❓ Question 6
Which statement is correct and why?
Anu: We inhale air.
Shanu: We inhale oxygen.
Tanu: We inhale air rich in oxygen.
📌 Answer:
✔️ Tanu’s statement is correct.
🔹 We inhale air, which contains many gases.
🔹 Oxygen forms only about 21% of air.
🔹 The body uses oxygen from this air for respiration.

🔒 ❓ Question 7
We often sneeze when we inhale a lot of dust-laden air. Why?
📌 Answer:
🔹 Dust irritates the lining of the nasal passages.
🔹 Nerve endings get stimulated.
🔹 Sneezing is a reflex action that removes dust and germs.
🔹 It helps keep the respiratory tract clean.

🔒 ❓ Question 8
Paridhi and Anusha were running. Afterward, Anusha was breathing faster. Give two possible reasons.
📌 Answer:
🔹 Anusha may have run faster or for a longer time.
🔹 Her muscles required more oxygen to release energy.
🔹 Faster breathing helps supply oxygen and remove carbon dioxide.

🔒 ❓ Question 9
Yadu performed an experiment with rice flour, saliva and iodine solution. What was he trying to test?
📌 Answer:
🔹 He was testing the action of saliva on starch.
🔹 Saliva contains the enzyme amylase.
🔹 It converts starch into sugar.
🔹 Iodine does not turn blue-black when starch is broken down.

🔒 ❓ Question 10
Rakshita passed inhaled air through lime water in one test tube and exhaled air in another. What was she investigating? How can she confirm it?
📌 Answer:
🔹 She was investigating the presence of carbon dioxide in exhaled air.
🔹 Lime water turns milky in the presence of carbon dioxide.
🔹 The test tube with exhaled air turns milky faster.
➡️ This confirms that exhaled air contains more carbon dioxide.

ADVANCE KNOWLEDGE

🌍 Life Inside Motion: Animals as Living Systems
Animals may look simple from outside—walking, eating, sleeping—but inside them runs an extraordinarily complex system. Every second, millions of chemical reactions occur silently to keep animals alive. These reactions together are called life processes.
🧠 Big idea:
An animal is not a single machine—it is a network of coordinated systems, all working together without rest.

🧠 What Are Life Processes Really?
Life processes are the basic activities that keep an organism alive and functioning.
In animals, these include:
🍽️ Nutrition
🔄 Respiration
🚚 Transportation
⚙️ Excretion
🧠 Coordination and control
⭐ If even one of these stops for long, life cannot continue.

🍽️ Nutrition in Animals: Fueling the Body
Animals cannot make their own food. They depend on other organisms.
🧠 Steps of animal nutrition:
Ingestion
Digestion
Absorption
Assimilation
Egestion
⭐ Food is not useful until it is broken down into simpler molecules.

🧪 Digestion: Breaking Down Complexity
Food contains large molecules.
🧠 Digestion:
Breaks complex food into simple forms
Allows absorption into blood
🧪 Different animals digest food differently:
Herbivores → plant digestion
Carnivores → meat digestion
Omnivores → mixed digestion
⭐ Special enzymes act like biological scissors.

🔄 Respiration: Energy Release, Not Just Breathing
⚠️ Misconception: Respiration means breathing
✅ Reality: Respiration is the release of energy from food
🧠 Breathing supplies oxygen; respiration uses oxygen.
🧪 Oxygen helps:
Break down food
Release energy
⭐ Energy released powers movement, growth, and repair.

🌬️ Types of Respiration in Animals
Animals use different respiratory systems.
🐟 Fish → gills
🐜 Insects → tracheal tubes
🐸 Frogs → skin and lungs
🧍 Humans → lungs
🧠 Design depends on habitat and body structure.

🚚 Transportation: Internal Delivery System
Once nutrients and oxygen are absorbed, they must reach every cell.
🧠 Transportation system:
Carries oxygen
Delivers nutrients
Removes wastes
⭐ Blood acts as a living transport fluid.

❤️ Heart: The Tireless Pump
The heart works nonstop.
🧠 It:
Pushes blood
Maintains pressure
Keeps circulation continuous
⭐ A human heart beats over 100,000 times a day.
🧠 Different animals have different heart designs depending on their needs.

⚙️ Excretion: Cleaning the Internal Environment
Life processes produce waste.
🧠 Excretion removes:
Nitrogenous wastes
Excess water
Harmful substances
⭐ Without excretion:
Cells would be poisoned
Internal balance would collapse
🧪 Kidneys are natural filters, working quietly day and night.

⚠️ Misconception vs Reality
⚠️ Misconception: Sweat is urine
✅ Reality: Sweat removes water and salts, not major wastes
⚠️ Misconception: Animals excrete only urine
✅ Reality: Carbon dioxide, sweat, and other wastes are also excreted

🧠 Coordination and Control: Silent Intelligence
Animals respond to their surroundings.
🧠 This requires:
Nervous system (fast control)
Hormonal system (slow control)
⭐ Together they allow:
Movement
Thinking
Survival decisions
🧠 A tiny nerve signal can save a life.

🌍 Life Processes and Habitat
Life processes adapt to environment.
🌊 Aquatic animals:
Extract oxygen from water
🏜️ Desert animals:
Conserve water
❄️ Polar animals:
Maintain body heat
⭐ Adaptation keeps life processes efficient.

🧬 Cellular Level: Where Life Really Happens
All life processes occur at cell level.
🧠 Inside cells:
Food is converted to energy
Wastes are formed
Repair happens
⭐ Cells are the true living units.

🚀 Modern Science: Understanding Animals Better
🚀 Scientists study:
Animal physiology
Disease mechanisms
Artificial organs
🧠 This knowledge helps:
Save endangered species
Treat diseases
Improve animal welfare

⚠️ Human Impact on Animal Life Processes
Pollution and climate change affect animals.
⚠️ Effects include:
Breathing problems
Water imbalance
Food chain disruption
🧠 Protecting habitats protects life processes.

⭐ Amazing Facts
⭐ Hummingbirds breathe over 250 times per minute
⭐ Blue whales have the largest hearts
⭐ Some animals can survive without oxygen temporarily
⭐ Ants communicate using chemical signals

🧠 Why Curious Minds Must Understand Life Processes
Understanding life processes:
Builds respect for life
Explains survival strategies
Connects biology with environment
🧠 It teaches that life is delicate yet powerful.

🌟 Final Thought
Animals live not by chance, but by perfect coordination.
🧠 Life processes are nature’s silent instructions that keep every animal alive, moment by moment.

Important Notice : The lessons and study materials up to July–August 2025 have been sent. Soon, after receiving feedback from teachers and students, we will deliver the latest and more innovative study materials for the upcoming months.

Important Notice : The lessons and study materials up to July–August 2025 have been sent. Soon, after receiving feedback from teachers and students, we will deliver the latest and more innovative study materials for the upcoming months.

Class 7 : Science – ( English ) : Lesson 9. Life Processes in Animals

EXPLANATION AND ANALYSIS

TEXTBOOK QUESTIONS

OTHER IMPORTANT QUESTIONS

ADVANCE KNOWLEDGE

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