2026 most important notes for the living world (biology)

The Living World – Description (Biology) Introduction The living world includes all living organisms present on Earth, such as plants, animals, microorganisms, and humans. Living organisms show certain characteristics that distinguish them from non-living things. Characteristics of Living Organisms 1. Growth Living organisms increase in size and mass. Plants continue growing throughout life, while animals grow up to a certain age. 2. Reproduction All living organisms reproduce to continue their species. Reproduction can be: Asexual reproduction – one parent involved Sexual reproduction – two parents involved 3. Metabolism All chemical reactions occurring inside the body are called metabolism. It includes: Anabolism – building up substances Catabolism – breaking down substances Metabolism is considered an important feature of life. 4. Cellular Organization All living organisms are made up of cells. The cell is the structural and functional unit of life. 5. Consciousness Living organisms can sense and respond to changes in their surroundings (stimuli). This ability is called consciousness. 6. Adaptation Organisms adapt to their environment for survival. These adaptations help them live in different habitats. Diversity in the Living World There are millions of living organisms on Earth. To study them easily, scientists classify them into groups. Taxonomy The branch of biology dealing with identification, naming, and classification of organisms is called taxonomy. Father of Taxonomy Carolus Linnaeus is known as the Father of Taxonomy. Taxonomic Categories Organisms are classified into different hierarchical categories: Species Genus Family Order Class Phylum/Division Kingdom Example: Human: Kingdom – Animalia Phylum – Chordata Class – Mammalia Binomial Nomenclature The scientific naming system introduced by Carolus Linnaeus is called binomial nomenclature. Rules: Scientific names have two words: Genus name Species name Genus starts with a capital letter. Species starts with a small letter. Names are written in italics. Example: Homo sapiens Importance of Classification Helps in identification of organisms Makes study of organisms easier Shows relationships among organisms Provides universal names worldwide