Life Processes in Animals
Every animal must take in food, get energy, move materials around and remove wastes to stay alive. This Class 7 Curiosity chapter explores the life processes in animals — nutrition and digestion, respiration, transport and excretion — using the human body as the main example.
Learning objectives
- List the main life processes in animals.
- Describe digestion of food.
- Explain respiration and its purpose.
- Describe transport and excretion.
Key concepts
Nutrition and digestion
Animals take in food for energy and growth, a process called nutrition. In humans, digestion breaks food into simpler substances the body can absorb. Food passes through the digestive tract — mouth, food pipe, stomach and intestines — where digestive juices act on it, and the nutrients are absorbed into the blood.
Respiration
Respiration is the process by which cells use oxygen to release energy from digested food, giving out carbon dioxide. We breathe in air to supply oxygen and breathe out to remove carbon dioxide; the lungs are the organs of breathing. The energy released powers all the body's activities.
Transport (circulation)
Materials must be carried around the body, which is the job of the circulatory system. Blood, pumped by the heart through blood vessels, carries oxygen and digested food to all body parts and brings back wastes like carbon dioxide. This continuous transport keeps every cell supplied.
Excretion
The wastes produced by the body must be removed, a process called excretion. In humans, the kidneys filter wastes from the blood to form urine, and carbon dioxide is removed through the lungs. Removing wastes keeps the body's internal environment clean and healthy.
Key definitions
- Nutrition
- The intake of food for energy, growth and repair.
- Digestion
- The breakdown of food into simpler absorbable substances.
- Respiration
- The release of energy from food using oxygen.
- Excretion
- The removal of waste products from the body.
Solved examples
Q1. Which organ pumps blood around the body?
Solution: The heart.
Q2. What gas is needed for respiration?
Solution: Oxygen.
Q3. Which organs remove waste as urine in humans?
Solution: The kidneys.
Common mistakes to avoid
- Confusing breathing with respiration (respiration releases energy in cells).
- Thinking digestion happens only in the stomach.
- Believing the heart makes blood (it pumps it).
- Forgetting that carbon dioxide is removed through the lungs.
Life Processes in Animals — MCQ Quiz
10 questions with instant feedback. Use number keys 1–4 to answer.
The intake of food for energy and growth is:
Practice questions
Short answer
What is respiration?
The release of energy from food using oxygen, giving out carbon dioxide.
Which system transports materials in the body?
The circulatory system (blood pumped by the heart).
Name the human excretory organs that form urine.
The kidneys.
Long answer
Describe nutrition and digestion in humans.
Nutrition is the process by which animals take in food to obtain energy and materials for growth and repair. In humans, the food taken in must be broken down into simpler substances before the body can use it, and this breakdown is called digestion. Food travels through the digestive tract — from the mouth, down the food pipe, into the stomach, and then into the intestines — where digestive juices act on it at each stage. The simple substances produced are absorbed into the blood, mainly in the intestine, and carried to all parts of the body, while the undigested material is removed. In this way the body gets the nutrients it needs from food.
Explain respiration, transport and excretion as life processes in animals.
Three life processes work together to keep an animal's body running. Respiration is the process in which cells use oxygen to release energy from digested food, producing carbon dioxide; we breathe in to supply oxygen through the lungs and breathe out to remove carbon dioxide. Transport, carried out by the circulatory system, uses blood pumped by the heart through blood vessels to carry oxygen and digested food to every part of the body and to bring wastes back. Excretion removes the wastes the body produces — in humans the kidneys filter wastes from the blood to form urine, and carbon dioxide leaves through the lungs. Together, these processes supply energy, deliver materials and keep the body clean.
HOTS (Higher Order Thinking)
Why does the body need both a transport system and a respiratory system?
Breathing supplies oxygen, but the blood transport system is needed to carry that oxygen to every cell and bring carbon dioxide back to be removed.
If the kidneys stopped working, why would the body be harmed?
Wastes would build up in the blood instead of being removed as urine, making the internal environment harmful.
Quick revision
Revision notes
- Main life processes: nutrition, respiration, transport, excretion.
- Digestion breaks food into simple substances absorbed by blood.
- Respiration uses oxygen to release energy, giving out CO₂.
- Heart + blood transport materials; kidneys excrete urine.
Key takeaways
- Animals digest food, release energy, transport materials and excrete wastes.
- Respiration releases energy using oxygen.
- Blood (pumped by the heart) is the body's transport.
Frequently asked questions
Is breathing the same as respiration?
No — breathing exchanges gases; respiration releases energy in cells using oxygen.
What does the circulatory system do?
It carries oxygen and food to body parts and removes wastes.
How are wastes removed in humans?
The kidneys remove urine and the lungs remove carbon dioxide.