At Bodhiclasses, we are passionate about making science fun, relatable, and easy to understand. Each chapter is not just a lesson — it’s a journey into the wonders of life and nature. Today, we bring you a comprehensive chapter analysis of Chapter 9 – Life Processes in Animals from the Class 7 Science textbook. This chapter beautifully connects our daily experiences — like eating food and breathing — with deeper scientific understanding.
Let’s explore the key concepts, section-wise breakdown, real-life applications, and important highlights from this chapter.
SECTION 9.1: Nutrition in Animals
➡️ 9.1.1 – Digestion in Human Beings
The process of digestion starts in the mouth, where mechanical digestion by teeth and chemical digestion by saliva begins. Saliva contains enzymes that convert starch into sugar, which is why chapati tastes sweet after chewing for a while.
Food travels down the oesophagus via peristalsis — wave-like muscular movements.
In the stomach, digestive juices (including acid and mucus) further break down proteins, while mucus protects the stomach lining from damage. The churned, semi-liquid food then enters the small intestine.
➡️ Role of Liver and Pancreas
- Liver secretes bile to neutralise stomach acid and emulsify fats.
- Pancreas secretes enzymes that break down carbohydrates, proteins, and fats.
The small intestine completes digestion and is the site of nutrient absorption. The inner lining has villi to increase surface area, allowing efficient absorption into the bloodstream.
➡️ 9.1.2 – Digestion in Other Animals
- Ruminants (like cows) swallow partially chewed grass, regurgitate it later for thorough chewing — a process called rumination.
- Birds lack teeth but have a gizzard that grinds food with swallowed stones.
This section highlights how digestive systems vary across species based on diet and habitat.
SECTION 9.2: Respiration in Animals
➡️ 9.2.1 – Respiration in Humans
The respiratory system includes:
- Nostrils
- Nasal passages with hairs and mucus that filter dust
- Windpipe
- Lungs containing tiny sacs called alveoli
In alveoli, oxygen from inhaled air is exchanged with carbon dioxide from the blood. This oxygen is then transported throughout the body for cellular respiration, where glucose is broken down to release energy:
Glucose + Oxygen → Carbon dioxide + Water + Energy
🧠 Key Concept: Breathing is the physical movement of air, while respiration is a chemical process that occurs in cells.
What We Breathe Out
Through experiments like passing exhaled air into lime water, students learn that exhaled air contains more carbon dioxide, turning lime water milky — a classic science activity.
9.2.2 – Respiration in Other Animals
- Mammals, birds, reptiles use lungs.
- Fishes breathe using gills that extract dissolved oxygen from water.
- Amphibians like frogs breathe through skin and lungs.
- Earthworms breathe through their moist skin.
This diversity of respiration methods shows how animals have adapted to their environment.
Key Diagrams and Figures in the Chapter: Life Processes in Animals
- Human Digestive System (Fig. 9.1)
- Movement of Food in Oesophagus (Fig. 9.2)
- Stomach Functions (Fig. 9.3)
- Alimentary Canal (Stretched View) (Fig. 9.4)
- Villi in Small Intestine (Fig. 9.5)
- Digestive System in Ruminants & Birds (Fig. 9.6, 9.7)
- Human Respiratory System (Fig. 9.8)
- Lung Model and Mechanism of Breathing (Fig. 9.9, 9.10)
- Gas Exchange in Alveoli (Fig. 9.12)
- Oxygen and CO₂ Levels in Inhaled vs. Exhaled Air (Fig. 9.13)
- Gills in Fishes (Fig. 9.14)
These visuals make the learning experience interactive and conceptually clear.
Major Takeaways from the Chapter: Life Processes in Animals
- Digestion transforms complex food into absorbable nutrients.
- Respiration provides the energy necessary for all life activities.
- Animals have evolved different systems for digestion and respiration, suited to their environment.
- Healthy habits like chewing food well, maintaining oral hygiene, and breathing practices support these life processes.
- Both science and traditional wisdom (like Ayurveda and yogic breathing) emphasise the importance of good digestion and respiration for overall well-being.
Real-Life Connections
- Chewing slowly helps digestion and even changes taste.
- Breathing through the nose filters harmful particles.
- Practices like pranayama and fermented foods support respiratory and digestive health.
- Awareness of diseases like celiac disease and COVID-19 link classroom knowledge with real-world health challenges.
Why This Chapter Life Processes in Animals Matters
This chapter not only explains how the human body functions but also nurtures awareness about:
- Nutrition
- Health
- Habits
- Ecosystem diversity
It bridges classroom science with daily habits, environmental adaptation, and traditional practices, creating holistic understanding for young learners.
Conclusion
Life Processes in Animals is more than just another science chapter — it’s a detailed look into the complex systems that make life possible. Understanding how we digest food and breathe not only enriches our scientific thinking but also encourages us to take better care of our body.
At Bodhiclasses, we aim to make these connections meaningful and memorable for every student.
Stay curious, stay mindful, and keep learning with us!
