🌟 Class 7 Science Curiosity – Chapter 9 Notes
🫀 Life Processes in Animals | Amresh Academy
📘 Introduction
All living organisms perform certain life processes to survive 🌱
👉 These include:
- 🍽️ Nutrition
- 🌬️ Respiration
- 💧 Excretion
- 🔄 Reproduction
⚙️ 1. Life Processes
👉 Essential for survival of animals
📌 Focus of this chapter:
- Nutrition (Digestion)
- Respiration
🍽️ 2. Nutrition in Animals
👉 Food provides energy ⚡
🧠 Key Concept:
- Complex food → broken into simpler substances
- Occurs in alimentary canal (mouth → anus)
🫃 3. Human Digestive System
👄 Mouth
- Teeth chew food
- Saliva breaks starch → sugar
🔄 Oesophagus
- Pushes food using wave-like movement (peristalsis)
🥣 Stomach
- Churns food
- Digestive juices break proteins
- Acid kills bacteria
- Mucus protects lining
🧪 Small Intestine
- Longest part (~6 m)
- Liver → bile
- Pancreas → digestive juice
- Villi absorb nutrients into blood
💧 Large Intestine
- Absorbs water & salts
- Forms stool
🚽 Anus
- Waste expelled (egestion)
🥗 Healthy Tips:
- Eat fiber-rich food 🍎
- Brush teeth twice daily 🪥
🐄 4. Digestion in Other Animals
🐄 Ruminants (cow):
- Chew food twice (rumination)
🐦 Birds:
- Use gizzard to grind food
🌬️ 5. Respiration in Animals
🫁 6. Human Respiratory System
🔹 Parts:
- 👃 Nostrils
- 🌫️ Nasal passages
- 🫁 Lungs (alveoli)
- 🦴 Rib cage
- ⬇️ Diaphragm
🔄 Breathing Mechanism:
🌬️ Inhalation:
- Ribs move up/out
- Diaphragm moves down👉 Air enters lungs
🌬️ Exhalation:
- Ribs move down/in
- Diaphragm moves up👉 Air goes out
🔬 Gas Exchange:
- Oxygen → enters blood
- Carbon dioxide → removed
⚗️ Equation:
👉 Glucose + Oxygen → Carbon dioxide + Water + Energy
📊 Air Comparison:
Type | Oxygen | CO₂ |
Inhaled | ~21% | ~0.04% |
Exhaled | ~16–17% | ~4–5% |
🐟 7. Respiration in Other Animals
- 🐦 Birds → Lungs
- 🐟 Fish → Gills
- 🐸 Amphibians → Skin + lungs
- 🐛 Earthworms → Moist skin
❤️ 8. Circulatory System
👉 Includes:
- ❤️ Heart
- 🩸 Blood
- 🧵 Blood vessels
👉 Functions:
- Transport oxygen & nutrients
- Remove waste
📌 9. Key Notes
💡 Good Practices:
- 🪥 Oral hygiene
- 🥗 Balanced diet
- 🧘 Breathing exercises
⚠️ Warning:
📌 Final Summary
👉 Life processes keep organisms alive 🌍
👉 Key systems:
- Digestive system 🍽️
- Respiratory system 🌬️
- Circulatory system ❤️
✨ Perfect for revision + exams + concept clarity 🚀
