๐ Class 7 Science Curiosity – Chapter 9 Notes
๐ซ Life Processes in Animals | Amresh Academy
๐ Introduction
All living organisms perform certain life processes to survive ๐ฑ
๐ These include:
- ๐ฝ️ Nutrition
- ๐ฌ️ Respiration
- ๐ง Excretion
- ๐ Reproduction
⚙️ 1. Life Processes
๐ Essential for survival of animals
๐ Focus of this chapter:
- Nutrition (Digestion)
- Respiration
๐ฝ️ 2. Nutrition in Animals
๐ Food provides energy ⚡
๐ง Key Concept:
- Complex food → broken into simpler substances
- Occurs in alimentary canal (mouth → anus)
๐ซ 3. Human Digestive System
๐ Mouth
- Teeth chew food
- Saliva breaks starch → sugar
๐ Oesophagus
- Pushes food using wave-like movement (peristalsis)
๐ฅฃ Stomach
- Churns food
- Digestive juices break proteins
- Acid kills bacteria
- Mucus protects lining
๐งช Small Intestine
- Longest part (~6 m)
- Liver → bile
- Pancreas → digestive juice
- Villi absorb nutrients into blood
๐ง Large Intestine
- Absorbs water & salts
- Forms stool
๐ฝ Anus
- Waste expelled (egestion)
๐ฅ Healthy Tips:
- Eat fiber-rich food ๐
- Brush teeth twice daily ๐ชฅ
๐ 4. Digestion in Other Animals
๐ Ruminants (cow):
- Chew food twice (rumination)
๐ฆ Birds:
- Use gizzard to grind food
๐ฌ️ 5. Respiration in Animals
๐ซ 6. Human Respiratory System
๐น Parts:
- ๐ Nostrils
- ๐ซ️ Nasal passages
- ๐ซ Lungs (alveoli)
- ๐ฆด Rib cage
- ⬇️ Diaphragm
๐ Breathing Mechanism:
๐ฌ️ Inhalation:
- Ribs move up/out
- Diaphragm moves down๐ Air enters lungs
๐ฌ️ Exhalation:
- Ribs move down/in
- Diaphragm moves up๐ Air goes out
๐ฌ Gas Exchange:
- Oxygen → enters blood
- Carbon dioxide → removed
⚗️ Equation:
๐ Glucose + Oxygen → Carbon dioxide + Water + Energy
๐ Air Comparison:
Type | Oxygen | CO₂ |
Inhaled | ~21% | ~0.04% |
Exhaled | ~16–17% | ~4–5% |
๐ 7. Respiration in Other Animals
- ๐ฆ Birds → Lungs
- ๐ Fish → Gills
- ๐ธ Amphibians → Skin + lungs
- ๐ Earthworms → Moist skin
❤️ 8. Circulatory System
๐ Includes:
- ❤️ Heart
- ๐ฉธ Blood
- ๐งต Blood vessels
๐ Functions:
- Transport oxygen & nutrients
- Remove waste
๐ 9. Key Notes
๐ก Good Practices:
- ๐ชฅ Oral hygiene
- ๐ฅ Balanced diet
- ๐ง Breathing exercises
⚠️ Warning:
๐ Final Summary
๐ Life processes keep organisms alive ๐
๐ Key systems:
- Digestive system ๐ฝ️
- Respiratory system ๐ฌ️
- Circulatory system ❤️
✨ Perfect for revision + exams + concept clarity ๐
