At Bodhiclasses, we believe learning should not just inform but inspire. Through every chapter, we aim to connect classroom concepts with real-life relevance, sparking curiosity and a lifelong love for learning. In today’s blog, let’s dive deep into a fascinating Class 7 Science chapter — Life Processes in Animals — where we explore how our body digests food and breathes in life.
Animals, like all living beings, perform vital functions such as nutrition, respiration, circulation, and excretion. These functions, known as life processes, ensure survival and health. This chapter focuses on two of these essential processes — nutrition and respiration — with an in-depth look into human systems and how they compare across animal species.
Section 1: Nutrition in Animals
1.1 The Journey of Food in Humans
- Mouth: Digestion begins with mechanical breakdown by teeth and chemical digestion via saliva, which contains enzymes that convert starch into sugar. Chewing food properly is the first step toward a healthy digestive process.
- Oesophagus (Food Pipe): Food is pushed down through rhythmic contractions called peristalsis.
- Stomach: Here, food is churned and mixed with digestive juices, hydrochloric acid, and mucus. Proteins begin to break down, and harmful microbes are neutralised.
- Small Intestine: The most crucial part! It receives secretions from the liver (bile) and pancreas (pancreatic juice) that help break down carbohydrates, proteins, and fats. The inner walls are lined with finger-like projections called villi that absorb nutrients into the bloodstream.
- Large Intestine: Absorbs water and salts from undigested food. The rest is converted into semi-solid stool and stored in the rectum before egestion through the anus.
1.2 Digestion in Other Animals
- Ruminants (e.g., cows, buffaloes): These animals exhibit rumination — they partially chew food, swallow it, regurgitate it later, and chew again for better digestion.
- Birds: Lack teeth but possess a muscular organ called the gizzard that grinds food with swallowed stones.
Section 2: Respiration in Animals
2.1 Human Respiratory System
- Breathing is the physical act of inhaling oxygen and exhaling carbon dioxide.
- The process involves nostrils, nasal passages (that filter dust), windpipe, and lungs protected by the rib cage.
- Within the lungs, the air reaches tiny balloon-like sacs called alveoli, where gas exchange happens — oxygen enters the blood, and carbon dioxide is expelled.
2.2 Respiration: A Cellular Process
- Inside the cells, glucose from digested food reacts with oxygen to release energy, carbon dioxide, and water. This is called cellular respiration.
- The process is summarized as:
Glucose + Oxygen → Carbon dioxide + Water + Energy
💡 Note: Breathing is a physical process, while respiration is a chemical process. Both are essential for survival.
2.3 Respiration in Other Animals
- Birds, reptiles, and mammals breathe through lungs.
- Fishes use gills to extract oxygen dissolved in water.
- Frogs (amphibians) use both lungs and skin for breathing.
- Earthworms breathe through moist skin.
Highlights and Insights [Life Processes in Animals]
- Proper chewing improves digestion by allowing enzymes like those in saliva to act efficiently.
- Healthy eating habits, oral hygiene, and fibre-rich foods support digestion.
- Practices like pranayama and box-breathing improve respiratory health.
- Ruminants like cows spend 8 hours daily chewing — highlighting nature’s amazing adaptations.
- Lime water tests reveal the presence of carbon dioxide in exhaled air — a simple yet powerful science experiment!
Final Thoughts [Life Processes in Animals]
From the food we eat to the air we breathe, our body is a marvel of engineering. Understanding how digestion and respiration work not only enriches our scientific knowledge but also helps us care for our health better. This chapter beautifully blends biology with everyday observations and cultural wisdom — from Ayurveda to breathing techniques like Tummo and Pranayama.
Stay curious, explore deeply, and never stop asking questions — that’s the Bodhiclasses way!
