Class 11 Biology - Chapter 1: The Living World (Notes)
Key Concepts
1. What is 'Living'?
- Living organisms show growth, reproduction, metabolism, cellular organization, consciousness.
- Growth: Increase in mass and number of individuals (plants grow continuously; animals grow up to
a certain age).
- Reproduction: Formation of new individuals; exception - mules, sterile worker bees, etc.
- Metabolism: All chemical reactions in a living body (anabolism + catabolism). It is the definitive
feature of life.
- Consciousness: Ability to sense environment and respond; most defining property of living beings.
2. Diversity in the Living World
- 1.7 to 1.8 million species described so far.
- Earth has huge biodiversity; needs identification and classification.
3. Taxonomy
- Definition: Science of naming, describing and classifying organisms.
- Carolus Linnaeus is the father of taxonomy.
- Binomial nomenclature:
* Two parts: Genus + species
* Ex: Homo sapiens
* Followed by rules of ICBN and ICZN
4. Systematics
Key Concepts
1. What is 'Living'?
- Living organisms show growth, reproduction, metabolism, cellular organization, consciousness.
- Growth: Increase in mass and number of individuals (plants grow continuously; animals grow up to
a certain age).
- Reproduction: Formation of new individuals; exception - mules, sterile worker bees, etc.
- Metabolism: All chemical reactions in a living body (anabolism + catabolism). It is the definitive
feature of life.
- Consciousness: Ability to sense environment and respond; most defining property of living beings.
2. Diversity in the Living World
- 1.7 to 1.8 million species described so far.
- Earth has huge biodiversity; needs identification and classification.
3. Taxonomy
- Definition: Science of naming, describing and classifying organisms.
- Carolus Linnaeus is the father of taxonomy.
- Binomial nomenclature:
* Two parts: Genus + species
* Ex: Homo sapiens
* Followed by rules of ICBN and ICZN
4. Systematics
