NCERT Class 7 Science Chapter 9
Life Processes in Animals
This chapter covers the essential life processes carried out by animals, including nutrition, respiration, transportation, and excretion, as studied in CBSE Class 7 Science. Students learn how animals obtain and digest food, how oxygen reaches cells, how nutrients and wastes are transported through the body, and how waste products are removed. The chapter builds a strong foundation for understanding animal physiology.
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Key Terms
- Nutrition
- The process by which organisms obtain and use food for energy, growth, and repair. In animals, it involves ingestion, digestion, absorption, assimilation, and egestion.
- Digestion
- The process of breaking down complex food molecules into simpler, soluble forms that can be absorbed into the blood and used by cells.
- Respiration
- The process by which organisms break down food (glucose) to release energy. Aerobic respiration uses oxygen, while anaerobic respiration occurs without oxygen.
- Circulatory System
- The system consisting of the heart, blood, and blood vessels that transports nutrients, oxygen, hormones, and waste products throughout the body.
- Excretion
- The process of removing metabolic waste products from the body. In humans, the kidneys filter blood and produce urine to remove waste like urea.
- Peristalsis
- The wave-like muscular contractions of the walls of the digestive tract that push food along from the oesophagus to the intestines.
Frequently Asked Questions
What are the main life processes in animals?▾
The main life processes in animals include nutrition (obtaining food), digestion (breaking down food), respiration (releasing energy from food), circulation (transporting substances), excretion (removing wastes), and reproduction.
How is food digested in the human body?▾
Digestion begins in the mouth where teeth break down food and saliva starts chemical digestion. Food then moves to the stomach where acid and enzymes break it down further. The small intestine completes digestion and absorbs nutrients, while the large intestine absorbs water and the remaining waste is expelled.
What is the difference between aerobic and anaerobic respiration?▾
Aerobic respiration uses oxygen to break down glucose, producing carbon dioxide, water, and a large amount of energy. Anaerobic respiration occurs without oxygen and produces less energy, along with lactic acid (in muscles) or alcohol and carbon dioxide (in yeast).
What is the role of the kidneys in excretion?▾
The kidneys filter the blood to remove waste products like urea, excess salts, and water. This filtered waste forms urine, which is stored in the bladder and expelled from the body through the urethra.
What does the circulatory system do in animals?▾
The circulatory system transports oxygen and nutrients to all body cells and carries away carbon dioxide and other waste products. The heart pumps blood through a network of arteries, veins, and capillaries that reach every part of the body.
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